The balanced chemical equation when sodium and oxygen react is as below
4 Na + O₂ → 2 Na₂O
Explanation
From equation above 4 moles of sodium (Na) react with 1 mole of oxygen (O₂) to produce sodium oxide ( Na₂O)
Since there is equal number number of atoms in side of reactants and in the side of product the equation is balanced.
For example there is 4 atoms of Na in side of reactant and 4 in side of product.
How many electrons does boron lose when forming a ion?
A. 1
B. 2
C. 3
D. 4
(NOT D)
(Answer) (C) 3
Boron is a non-metal with atomic number 5. The electronic configuration of boron atom is [He]2s^22p^1.
Boron atom has the tendency to obtain stable electronic configuration like its nearest noble gas helium by losing electrons. Boron atom usually loses 3 electrons from its outermost electronic shell to form a cation with +3 charge.
Therefore, boron atom loses 3 electrons while forming an ion.
A solution is made by dissolving 1.00 moles of sodium chloride (NaCl) in 155 grams of water. If the molal boiling point constant for water (Kb) is 0.51 °C/m, what would be the boiling point of this solution? Show all of the work needed to solve this problem.
Answer:
106.6 °C
Step-by-step explanation:
The formula for boiling point elevation ΔTb is
ΔTb = iKb·b
where
i = the van't Hoff i# factor
Kb = the molal boiling point elevation constant
b = the molal concentration of the solution
=====
Data
i = 2, because 1 mol of NaCl gives 2 mol of ions in solution.
Kb = 0.51 °C·mol·kg⁻¹
b = 1.00/0.155
b = 6.452 mol·kg⁻¹
=====
Calculations
ΔTb = 2 × 0.51 × 6.452
ΔTb = 6.58°C
Tb = Tb° + ΔTb
Tb = 100 + 6.58
Tb = 106.6 °C
One of a kind static electricity is a result of electrons moving into an object from another object. What is another way static electricity can build up in an object?
Another way static electricity can build up in an object is induction. Induction is the transfer of electrons from one part of an object to another part, caused by the electric field of another object, without the two objects touching.
When the temperature in a room increases from 25c to 33c what changes from a solid to a liquid
Answer:
Gallium
Explanation:
*I think it’s either the first one or the last one, but I’m just not sure.
Nitrogen dioxide gas is dark brown in color and remains in equilibrium with dinitrogen tetroxide gas, which is colorless.
2NO2(g) ⇌ N2O4(g)
When the light brown color equilibrium mixture was moved from room temperature to a lower temperature, the mixture turned lighter brown in color. Which of the following conclusions about this equilibrium mixture is true?
This reaction is endothermic because the system shifted to the left on cooling.
This reaction is endothermic because the system shifted to the right on cooling.
This reaction is exothermic because the system shifted to the left on cooling.
This reaction is exothermic because the system shifted to the right on cooling.
Answer:
This reaction is exothermic because the system shifted to the right on cooling.
Step-by-step explanation:
2NO₂ ⇌ N₂O₄
brown colourless
According to Le Châtelier's Principle, when a stress is applied to a system at equilibrium, the system will respond in a way that tends to relieve the stress.
You applied a stress by cooling the system (removing heat). The system responded by moving in a direction that created more heat.
The mixture became lighter brown on cooling, so the position of equilibrium must have shifted to the right to generate the heat.
The reaction is exothermic.
When the light brown color equilibrium mixture was moved from room temperature to a lower temperature, the mixture turned lighter brown in color shows this reaction is exothermic because the system shifted to the right on cooling.
What is equilibrium law?According the the equilibrium law, if any external element is added in the equilibrium state, ten the whole reaction will shifts to that side which reduces the effect of that additional element.
Given chemical reaction is:
2NO₂(g) ⇌ N₂O₄(g)
Where NO₂ shows brown color and N₂O₄ is colorless gas. If we notice a light brown color of the mixture when we moved from room temperature to a lower temperature then the reaction will shifts to the right side and will show exothermic behavior to overcome the external effect.
Hence, option (d) is correct.
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A 0.1326 g sample of magnesium was burned in an oxygen bomb calorimeter. the total heat capacity of the calorimeter plus water was 5,760 j/°c. if the temperature rise of the calorimeter with water was 0.570°c, calculate the enthalpy of combustion of magnesium. mg(s) + 1/2o2(g) →mgo(s)
The enthalpy of combustion of magnesium in this experiment is approximately -602 kJ/mol, which was determined by dividing the total heat transferred (calculated from the calorimeter's heat capacity and temperature change) by the number of moles of magnesium burnt.
Explanation:
In the experiment described, a small piece of magnesium was burnt in a oxygen bomb calorimeter, leading to a recorded temperature rise in the calorimeter and the water it contains. The enthalpy of combustion of magnesium can be determined from these values by using the equation q = mcΔT, where q is the heat transferred, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. In this case, the total heat transferred (q) is the heat capacity of the calorimeter and the water times the temperature change, or 5760 J/°C * 0.570 °C = 3283.2 J. The molar enthalpy of combustion can then be calculated by determining the moles of Mg burnt (0.1326 g / 24.305 g/mol = 0.00545 mol) and dividing the heat produced by the moles of Mg burnt (3283.2 J / 0.00545 mol = -602 kJ/mol). Therefore, when rounded to 3 significant figures, the enthalpy of combustion of magnesium is around -602 kJ/mol.
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Given that Cu + 2HCI Cu2+ + 2CI- + H2(g) has an overall reduction potential of –0.34 V, what is a valid prediction about how this reaction works? The reaction is not spontaneous and will require energy to proceed. The reverse reaction would require energy input in order to occur. The half reactions would both occur spontaneously. The reaction is not spontaneous, and it is impossible to make it occur.
Cu + 2HCI → Cu²⁺ + 2CI⁻ + H2(g)
has an overall reduction potential of –0.34 V
The correct option is:
The reaction is not spontaneous and will require energy to proceed.
Since the overall reduction potential is negative,the reaction is not spontaneous and it requires energy to proceed.
The reaction is
Cu(s) + 2HCI(aq) ---> Cu⁺² + 2CI⁻ + H₂(g)
The given E⁰cell = -0.34
The overall reduction potential is negative
A reaction is said to be spontaneous it is ΔG° is negative
The relation between ΔG° and Electrode potential is
ΔG° = -nFE°cell
as given that
E°cell = -0.34 V
The overall value of ΔG° will be positive and hence reaction must be non spontaneous
so
The reaction is not spontaneous and will require energy to proceed.
the equation below shows the decomposition of lead nitrate. how many grams of oxygen are produced when 11.5g NO2 is formed?
2Pb(NO3)2(s) -> 2PbO(s) + 4NO2(g) + O2(g)
a. 2.88 g
b. 2.00 g
c. 32.0 g
d. 1.00 g
PLEASE AND THANK YOU IN ADVANCE
Final answer:
2.00 g of oxygen is produced ,option B
Explanation:
To determine how many grams of oxygen are produced when 11.5 g of NO2 is formed, we can use the stoichiometry of the balanced chemical equation:
2 Pb(NO3)2(s) = 2 PbO(s) + 4 NO2(g) + O2(g)
From the equation, we see that 4 moles of NO2 are produced alongside 1 mole of O2. First, we find the number of moles of NO2 that 11.5 g corresponds to:
Molar mass of NO2 = 14.01 (N) + (2 *16.00) (O) = 46.01 g/mol
Moles of NO2 = 11.5 g / 46.01 g/mol
Then, we take into account the mole ratio between NO2 and O2, which is 4:1:
Moles of O2 = (Moles of NO2) times (1 mole O2 / 4 moles NO2)
Finally, we find the mass of O2 produced:
Molar mass of O2 = 2 times 16.00 g/mol = 32.00 g/mol
Mass of O2 = (Moles of O2) times (32.00 g/mol)
By going through the calculations, we find that the mass of O2 produced is 2.00 g, which corresponds to option (b).
The salts NaCl and CaCl2
(a) are good conductors of electricity
(b) have positive charges
(c) have the same crystal lattice of energy
(d) are held together by ionic bond
Answer: The correct answer is Option a and d.
Explanation: Both the salts are ionic in nature because when dissolved in water, they dissociate into their respective ions.
Ionic compounds are held together by ionic bond. They are neutral compounds as both positive and negative charges neutralize each other. These compounds are also good conductors of electricity because of the presence of ions.
As both the salts have different molecular formula, both of them will have different crystal lattice system and hence, different crystal lattice energy.
From the above information, the correct options are option a and option d.
Answer:
D
Explanation:
both a and b
that i a correct
answer
What is the momentum of a 750-kg car traveling at a velocity of a 25 m/s?
Momentum = mass x velocity 750x25 = 18750 kg-m/s.
explain how atoms(ions) are held together in an ionic bond. Give an example of an ionic compound
Ionic bond is described as the chemical bond between two oppositely charged ions. In ionic bond the metal loses electron forming a positively charged cation and a non metal which accept the cation to form a negatively charged anion. In ionic bond the atoms are held together by electrostatic force of attraction. In ionic bond the anions and cations are present in the ratio where the total charge of the compound becomes zero. For example, Let us consider NaCl compound. An atom of the sodium has three electrons in its valency shell and the electrons are removed from the outer most shell by applying the energy of 5.14 electron volts. The chlorine atom lacks an electron to attain stable electronic configuration and it accepts the electron from the sodium by releasing 3.62 electron volts of energy which means that it takes only 1.52 electron volts of energy to donate an electron to chlorine when both the atoms are far apart. When these electrons are brought together their electric potential becomes more negative. This means that if the neutral sodium and chlorine atoms are found themselves closer it would be energetically favourable to transfer electrons from sodium to chlorine thus resulting in the formation of the ionic bond.
The ions in an ionic bond are held together by electrostatic attraction between the anions and cations in the compound.
For example, sodium chloride [NaCl] (more commonly known as salt) has positively charged sodium [Na+] ions, or cations, and negatively charged chlorine [Cl-] ions, or anions, holding the compound together.
Which of the following pairs of elements is most likely to form an ionic bond?
A.
carbon and chlorine
B.
phosphorous and bromine
C.
sulfur and oxygen
D.
sodium and sulfur
Answer is: D. sodium and sulfur.
When the electronegativity difference is greater, the bond polarity is increasing..
Electronegativity (χ) is a property that describes the tendency of an atom to attract a shared pair of electrons.
Atoms with higher electronegativity attracts more electrons towards it, electrons are closer to that atom.
Δχ(Na-S) = 2.6 - 0.95 = 1.655; electronegativity difference between sodium and sulfur.
Ionic bond is the electrostatic attraction between oppositely charged ions (cations and anions).
Sodium is metal (forms cation) and sulfur is nonmetal (forms anion).
The tropopause is best described as which of the following?
The lowest layer of Earth's atmosphere is called troposphere.The layer immediately next to troposphere is called Stratosphere. The boundary layer between troposphere and stratosphere is described as tropopause.
The tropopause is the transition layer between the troposphere and the stratosphere in Earth's atmosphere. It is located at an altitude of about 12-15 km, and it is the coldest part of the atmosphere.
Explanation:The tropopause can be defined as the transition layer between the troposphere and the stratosphere in Earth's atmosphere. It is located at an altitude of about 12-15 km (7-8 miles), and it is the coldest part of the atmosphere. The temperature in the troposphere decreases steadily with increasing altitude, but at the tropopause, the temperature starts warming again due to the absorption of UV radiation by ozone in the stratosphere.
When 25.0 grams of water are cooled from 20.0 degrees Celsius to 10.0 degrees Celsius the number of joules of heat energy released is?
Heat energy released here
Q = mass x specific heat capacity of water x deltaT
= 25.0 x 4.184 x (-10.0)
= - 1046 Joules
1046 Joules of heat energy is released in this process.
Answer: The amount of heat released is -1046 J
Explanation:
To calculate the amount of heat released, we use the equation:
[tex]q=mc\Delta T[/tex]
where,
q = heat released = ?
m = mass of water = 25.0 g
c = specific heat capacity of water = 4.184 J/g.°C
[tex]\Delta T[/tex] = change in temperature = [tex]T_2-T_1=(10.0-20.0)^oC=-10.0^oC[/tex]
Putting values in above equation, we get:
[tex]q=25.0g\times 4.184J/g.^oC\times (-10.0^oC)\\\\q=-1046J[/tex]
Hence, the amount of heat released is -1046 J
How many moles of gas are there in a 45.0 L container at 25.0 °C and 500.0 mm Hg?
You can solve this by utilizing the ideal gas law, PV=nRT. P is pressure, V is volume, n is the number of moles, R is a constant (depends on the unit of pressure), and T is the temperature (in Kelvins).
500.0mmHg- convert to atm
=0.65789atm (do sig figs last)
25.0 C- convert to K
25.0 +273= 298K
PV=nRT
0.65789atm times 45.0L equals n (the variable) times R (0.08206L atm mol^-1 K^-1) times 298K
Isolate the variable, n and plug into a calculator.
I hope this helped!
Answer: The moles of gas is 1.21 moles.
Explanation:
To calculate the moles of gas, we use the equation given by ideal gas which follows:
[tex]PV=nRT[/tex]
where,
P = pressure of the gas = 500.0 mmHg
V = Volume of the gas = 45.0 L
T = Temperature of the gas = [tex]25^oC=[25+273]K=298K[/tex]
R = Gas constant = [tex]62.364\text{ L.mmHg }mol^{-1}K^{-1}[/tex]
n = number of moles of gas = ?
Putting values in above equation, we get:
[tex]500.0mmHg\times 45.0L=n\times 62.3637\text{ L.mmHg }mol^{-1}K^{-1}\times 298K\\\\n=\frac{500.0\times 45.0}{62.364\times 298}=1.21mol[/tex]
Hence, the moles of gas is 1.21 moles.
calculate the enthalpy change when 4.00 mol Cl2O7 is produced according to the following balanced equation:
2Cl2(g) + 7O2(g) + 130kcal -> 2Cl2O7(g)
a. 1040 kcal
b. -260 kcal
c. 260 kcal
d. -1040 kcal
** if you could explain it as well, that would be much appreciated !! if not, thats okay too its multiple choice
So the equation is,
2Cl2(g) + 7O2(g) + 130kcal -> 2Cl2O7(g)
from this , ΔH°rxn=[tex]130kcal.mol^{-1}[/tex]
[tex]mol^{-1}[/tex] is mentioned because it is for per mole of reaction. So for 4. moles of the product [tex]2Cl_{2} O_{7}[/tex] we need 4/2 moles of reaction to be used to calculate associated enthalphy change for the reaction.
Therefore[tex]4/2*130=260 kcal[/tex]
Compare the radio waves broadcasts by the two stations, WIL-92.3 and KSHE-94.7
A. Which station broadcasts waves with more energy?
B. Which station broadcasts waves with a shorter wavelength
C. Which stations broadcasts waves with a higher frequency?
The frequency of radio waves at the two stations are:
1. WIL-92.3 : Frequency = 92.3 MHz (mega hertz)
2. KSHE-94.7 : Frequency = 94.7 MHz
The wavelength (λ) and frequency (ν) are related as:
ν = c/λ ------(1)
Energy (E), frequency (ν) and wavelength (λ) are related as:
E = hν -----(2)
(or)
E = hc/λ ----(3)
A) Based on equation (2), higher the frequency higher is the energy. Therefore, station KSHE broadcasts waves with higher energy
B) Based on equation (1), higher the frequency lower will be the wavelength. Station KSHE will broadcast waves with shorter wavelength
C) KSHE will broadcast waves with higher frequency
Station KSHE-94.7 broadcasts waves with more energy, a shorter wavelength, and a higher frequency compared to WIL-92.3, as higher frequencies correspond to more energy and shorter wavelengths.
Explanation:In comparing radio wave broadcasts of WIL-92.3 and KSHE-94.7, we need to consider frequency, energy, and wavelength properties of radio waves. Here is how they relate:
Higher frequency corresponds to greater energy and shorter wavelength.Lower frequency corresponds to lesser energy and longer wavelength.Given that,:
Station KSHE-94.7 broadcasts waves with more energy, since it operates at a higher frequency (94.7 MHz) compared to WIL-92.3.Station KSHE-94.7 broadcasts waves with a shorter wavelength, as shorter wavelengths are associated with higher frequency transmissions.Station KSHE-94.7 broadcasts waves with a higher frequency, as is evident from their respective frequencies - the higher the frequency, the higher the energy of waves.Therefore, all the three properties are higher for KSHE-94.7 as compared to WIL-92.3.
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Which electrons in a calcium atom in the ground state have the greatest effect on the chemical properties of calcium
Answer is: the two electrons in the fourth shell.
Atomic number of calcium is 20, it means that it has 20 protons and 20 electrons, so atom of calcium is neutral.
Electron configuration of calcium atom: ₂₀Ca 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²; calcium has two valence electrons (4s²).
In reactions it lose those two electrons ang form cation with positive charge 2+.
Atomic number is the number of protons, which is characteristic of a chemical element.
Beryllium, magnesium,calcium and strontium are alkaline earth metals. The elements have very similar properties.
Alkaline earth metals have in common an outer s- electron shell (two electrons).
How many atoms are in one mole of gold? A) 1.97 x 1023 atoms. B) 6.02 x 1023 atoms C) 79 atoms. D) 197 atoms
B. Is the Answer 6.022 * 1023
Answer: B) [tex]6.022\times10^{23}[/tex] atoms.
Explanation:
According to the International System of units ,
A mole is basically denotes a unit that contains [tex]6.022\times10^{23}[/tex] of atoms.
It is also known as Avagadro Number.
Similarly, the number of atoms in one mole of gold = [tex]6.022\times10^{23}[/tex]
hence, the correct answer is B) [tex]6.022\times10^{23}[/tex] atoms.
Kevin has 5 fish in his fish tank jasmine has 4 times as many fish as Kevin.How many fish does jasmine have?
Which of these is a renewable resource? A) Gasoline that contains some alcohol B) Wind produced by the uneven heating of Earth's surface C) Natural gas pumped from deep underground D) None of these
Answer is: B) Wind produced by the uneven heating of Earth's surface.
Gasoline is a mixture of many different hydrocarbons: alkanes (paraffins), cycloalkanes and alkenes (olefins). It is not renewable resource, because every year is less and less gasoline.
Natural gas is usualy methane, it is not renewable recourse.
Wind consists of the bulk movement of air.
Final answer:
Wind produced by the uneven heating of Earth's surface is the renewable resource among the options provided.
Explanation:
Among the listed options, the renewable resource is B) Wind produced by the uneven heating of Earth's surface. Renewable energy sources such as wind can be replenished within a human timescale and do not deplete. Gasoline, even if it contains some alcohol, is not renewable because it is derived from petroleum which is a finite resource. Natural gas, while it may be used alongside renewable resources, is also non-renewable as it cannot be replenished within a human timescale once it's extracted from deep underground.
Help me number 16 and 17
16) Chemical equation: Ca + H₃PO₄ → Ca₃(PO₄)₂ + H₂.
Oxidation reaction: Ca⁰ → Ca⁺² + 2e⁻ /×3.
3Ca⁰ → 3Ca⁺² + 6e⁻
Reduction reaction: 6e⁻ + 2H₃⁺¹ → 3H₂⁰.
Calcium change oxidation number from 0 to +2 (oxidation) and hydrogen change oxidation number from +1 to 0 (reduction).
Balanced chemical equation: 3Ca + 2H₃PO₄ → Ca₃(PO₄)₂ + 3H₂.
Calcium is stronger reducing agent than hydrogen, gives electrons easier.
This is example of single displacement reaction.
Single displacement is reaction where neutral element metal or nonmetal become an ion as it replaces another ion in a compound.
17) Balanced chemical equation:
3Ca(s) + 2H₃PO₄(aq) → Ca₃(PO₄)₂(aq) + 3H₂(g).
Ionic equation: 3Ca + 6H⁺ + 2PO₄³⁻ → 3Ca²⁺ + 2PO₄³⁻ + 3H₂.
Net ionic equation: 3Ca + 6H⁺ → 3Ca²⁺ + 3H₂.
A spectator ion is an ion that exists as a reactant and a product in a chemical equation.
A spectator ion is phospate anion PO₄³⁻.
In a certain organic compound, one of the carbon atoms is bonded to three atoms. One of these is a carbon atom and the other two are hydrogen atoms. What type of bond exists between the two carbon atoms?
Double Covalent
Ionic
Ion Dipole
Since the C is bonded to 2 H atoms,
it needs two more bonds to complete the octet of C(as C forms four bonds in total),hence C-C bond is double covalent bond
The bonded C atom is shown as bold C here:
-C=CH2
The bond between the two C atoms is Double Covalent.
The type of bond that exists between the two carbon atoms in this organic compound is a double covalent bond.
In a double covalent bond, two pairs of electrons are shared between the two carbon atoms. Each carbon atom contributes one electron from its outermost electron shell to form a strong and stable bond. This sharing of electrons allows both carbon atoms to satisfy the octet rule, which states that atoms tend to gain, lose, or share electrons to achieve a stable configuration with a full outer electron shell, typically containing eight electrons.
Covalent bonds occur when atoms share electrons to achieve a stable electron configuration. In the case of a double covalent bond, there are two pairs of shared electrons between the two carbon atoms. This bond is strong and requires a significant amount of energy to break, making it a key characteristic of many organic compounds with double bonds, such as alkenes and some functional groups in organic chemistry.
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How many particles are in one mole?
A.
6.022 × 1023
B.
2.066 × 1023
C.
6.023 × 1022
D.
3.026 × 1022
Your answer is A
6.02 × 1023 particles
Answer: [tex]6.022\times 10^{23}[/tex]
Explanation: According to Avogadros law, one mole of any substance contains a fixed number of particles i.e [tex]6.022\times 10^{23}[/tex] particles (atoms, molecules or ions) which is also known by the name Avogadro's number.
For example: 1 mole of [tex]O_2[/tex] molecule contains [tex]6.022\times 10^{23}[/tex] molecules of oxygen.
1 mole of [tex]He[/tex] contains [tex]6.022\times 10^{23}[/tex] atoms of helium.
PLEASE HELP ASAP!! CHEMISTRY BALANCING EQUATIONS!
How many liters of NH3 at stp will react with 5.3g O2 to form NO2 and water?
4NH3(g) + 7O2(g) -> 4NO2 + 6H2O(g)
A. 0.00423L
B. 2.12L
C.3.03L
D. 6.49L
Answer:
B. 2.12 L
Step-by-step explanation:
We know we will need a balanced chemical equation with masses and molar masses, so, let's gather all the information in one place.
M_r: 32.00
4NH₃(g) + 7O₂(g) ⟶ 4NO₂ + 6H₂O(g)
m/g: 5.3
(a) Moles of O₂
Moles of O₂ = 5.3 × 1/32.00
Moles of O₂ =0.166 mol
=====
(b) Moles of NH₃
The molar ratio is 4 mol NH₃= 7 mol O₂.
Moles of NH₃ = 0.166 × 4/7
Moles of NH₃ = 0.0946 mol NH₃
=====
(c) Volume of NH₃ at STP
STP is 1 bar and 0 °C. At STP, the molar volume of a gas is 22.71 L.
Volume of NH₃ = 0.0946 ×22.71/1
Volume of NH₃ = 2.15 L
=====
It looks as if you are using the old (pre-1982) definition of STP.
Under that definition, the molar volume of a gas at STP was 22.41 L.
The volume of NH₃ is then 2.12 L.
Generally, when going down a group on the periodic table:
atomic radii decrease
ionic radii increase
electronegativity increases
reactivity decreases
Generally when we move down the group on a periodic table the atomic radii increases as the valency electrons occupy higher levels due to the increasing quantum number. Hence the atomic radii increases down the group.
The ionic radii increases down the group because while we move down the group the elements gain electrons and form ions called anions as an additional electron occupies the orbital the ions get bigger in size. Hence the ionic radii increase.
Electronegativity is described as the ability to attract and bind with electrons and it is a qualitative property. It decreases as we move down the group because the distance between the valency electrons and the nucleus increases. Hence electronegativity decreases down the group.
Reactivity increases as we move down the group as the metals have the tendency to lose electron form its outer shell.
Therefore the answer is ionic radii increases.
Two electrons are found in the same atom. One has the quantum number set (3, 2, 0, +?), and the other has the quantum number set (3, 1, 0, +?). They share thea same sub level but differentt orbitalsb same orbital but different spin directionsc same energy level but different sublevelsd same type of sub level but found in different energy sub levels
D. Same energy level but different sublevel.
ExplanationThere are four quantum numbers [1]:
n, the principal quantum number,l, the orbital angular momentum quantum number,[tex]m_l[/tex], the magnetic quantum number, and[tex]m_s[/tex], the electron spin quantum number.As their names might suggest:
n determines the main energy level of an electron. l determines the type of sublevel of an electron.Each sublevel might contain more than one orbital. [tex]m_l[/tex] gives the orbital of an electron.Each orbital contains up to two electrons. [tex]m_s[/tex] tells two electrons in the same orbital apart.The two electrons in question come from the same atom. The question suggests that they have the same n, [tex]m_l[/tex], and [tex]m_s[/tex]. As a result, both electrons are in main energy level n = 3. They share the same spin.
However, the two electrons differ in their value of l.
l = 2 for the first electron. It belongs to a d sublevel. l = 1 for the second electron. It belongs to a p sublevel. Reference[1] Kamenko, Anastasiya, et. al, "Quantum Numbers", Physical & Theoretical Chemistry, Chemistry Libretexts, 24 Mar 2017.
The element bromine, Br, has a larger atomic radius than A) Cu, O and Ba B) I, Cu, and Ba C) F and Kr D) O, F, and Kr
The answer is: D) O, F, and Kr.
Atomic radius of bromine (Br) is 114 pm.
Atomic radius of oxygen (O) is 73 pm.
Atomic radius of fluorine (F) is 72 pm.
Atomic radius of krypron (Kr) is 112 pm.
The atomic radius of a chemical element is a measure of the size of its atom.
The atomic radius varies with increasing atomic number, but usually increases because of increasing of number of electrons.
The atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.
Question 1 (True/False Worth 2 points)
(04.03 LC)
When Pb and AlCl3 react together, lead (Pb) can replace aluminum (Al) in the compound because lead is lower on the activity series.
True
False
Question 2(Multiple Choice Worth 4 points)
(04.03 MC)
Which of the following equations has the correct products and is balanced correctly for a reaction between Na3PO4 and KOH?
Na3PO4 + 3KOH → 3NaOH + K3PO4, because K retains the same charge throughout the reaction
Na3PO4 + KOH → Na3OH + KPO4, because K increases in charge from 1+ to 3+ when it is replaced
Na3PO4 + KOH → 3NaOH + K3PO4, because K retains the same charge throughout the reaction
Na3PO4 + KOH → Na3OH + K3PO4, because K increases in charge from 1+ to 3+ when it is replaced
Question 3(Multiple Choice Worth 4 points)
(04.03 LC)
Which of the following is a single replacement reaction?
Ba(OH)2 + H2SO4 → BaSO4 + 2H2O
2Mg + O2 → 2MgO
H2O+ CO2 → H2CO3
Zn + H2SO4 → ZnSO4 + H2
Question 4(Multiple Choice Worth 4 points)
(04.03 MC)
Sodium metal reacts with water to produce hydrogen gas.
What best describes this reaction?
A single replacement reaction takes place because sodium is less reactive than hydroxide ions.
A double replacement reaction takes place because sodium is less reactive than hydroxide ions.
A double replacement reaction takes place because sodium is more reactive than hydrogen.
A single replacement reaction takes place because sodium is more reactive than hydrogen.
Question 5 (True/False Worth 2 points)
(04.03 LC)
A single replacement reaction is a reaction in which one element replaces a similar element within a compound.
True
False
Question 6(Multiple Choice Worth 4 points)
(04.03 MC)
The table shows the nature of reactants and products formed in a certain type of chemical reaction.
Nature of Reactants and Products
Reactants Products
Metal + Ionic compound Metal + Ionic compound
Which of the following is true about the type of chemical reaction?
It is a single replacement reaction, and the anions in the two ionic compounds are different.
It is a single replacement reaction, and the cations in the two ionic compounds are different.
It is a double replacement reaction, and the anions in the two ionic compounds are different.
It is a double replacement reaction, and the cations in the two ionic compounds are different.
1) Answer is: False.
Balanced chemical reaction: Pb + AlCl₃ → no reaction.
The reactivity series is a series of metals from highest to lowest reactivity. Metal higher in the reactivity series will displace another.
Aluminium (Al) is higher in activity series than lead (Pb).
That means aluminium (Al) is stronger reducing agent than lead and gives electrons easier.
This series are used to summarize information about the reactions of metals with acids or water, double displacement reactions (more reactive metals displace metals with lower reactivity) and the extraction of metals from their ores.
2) Answer is: Na3PO4 + 3KOH → 3NaOH + K3PO4, because K retains the same charge throughout the reaction.
This chemical reaction is double displacement reaction - cations (K⁺ and Na⁺) and anions (PO₄³⁻⁻ and OH⁻) of the two reactants switch places and form two new compounds.
Na₃PO₄ is sodium phosphate.
KOH is potassium hydroxide.
NaOH is sodium hydroxide.
K₃PO₄ is potassium phosphate.
3) Answer is: Zn + H2SO4 → ZnSO4 + H2.
Single replacement is reaction where neutral element metal or nonmetal become an ion as it replaces another ion in a compound.
In this balanced chemical reaction zinc (Zn) replaces hydrogen (H).
Zinc changes oxidation number from 0 to +2 (this is oxidation) and hydrogen change oxidation number from +1 to 0 (reduction).
4) Answer is: A single replacement reaction takes place because sodium is more reactive than hydrogen.
Balanced chemical reaction:
2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g).
Single replacement is reaction where neutral element metal or nonmetal become an ion as it replaces another ion in a compound.
In this balanced chemical reaction sodium (Na) replaces hydrogen (H).
Sodium changes oxidation number from 0 to +1 (oxidation) and hydrogen change oxidation number from +1 to 0 (reduction).
5) Answer is: True.
For example, balanced chemical reaction:
Ca + 2HCl → H₂ + CaCl₂.
Reduction hald reaction: 2H⁺ + 2e⁻→ H₂.
Oxidation half reaction: Ca⁰ → Ca²⁺ + 2e⁻.
In this balanced chemical reaction calcium (Ca) replaces hydrogen (H).
In this chemical reaction, calcium lost two electrons (oxidation, change oxidation number from 0 to +2) and hydrogen gain that two electrons (reduction, change oxidation number from +1 to 0).
6) Answer is: It is a single replacement reaction, and the cations in the two ionic compounds are different.
For example, balanced chemical reaction:
Ba + MgSO₄ → BaSO₄(s) + Mg.
In this balanced chemical reaction barium (Ba) replaces magnesium (Mg), because barium is higher at activity series.
Sulfate anion (SO₄²⁻) is the same in two ionic compounds, but cations (Mg²⁺ and Ba²⁺) changes.
Single Displacement is reaction where neutral element metal or nonmetal become an ion as it replaces another ion in a compound.
Which of the following statements about energy in systems is true? Energy can be transferred or transformed inside or outside of a system, but energy cannot be destroyed. The total amount of energy in a system must be equal to the total amount of matter in that system. When energy is transferred or transformed within a system, some matter must be changed into energy so that the total amount of energy remains constant.
According to first law of thermodynamics, energy can neither be formed nor be destroyed but can be converted from one form to another.
thus the statement that Energy can be transferred or transformed inside or outside of a system, but energy cannot be destroyed, is true statment.
Answer:
Energy can be transferred or transformed inside or outside of a system, but energy cannot be destroyed.
Explanation:
A popular principle in science is known as the principle of conservation of energy. It states that energy cannot be created nor destroyed but can be converted from one form to another.
In a system, energy transformations are possible and does happen though inefficiently according to the laws of thermodynamics but energy can never be destroyed following the laws of thermodynamics.