A canoe displaces 100 L of water. Water weighs 9.8 N/L. What is the buoyant force on the canoe?

Electrons in an atom are held there by the force of attraction exerted by the positive charge of the nucleus on the negative charge of the electron. Energy is required to remove an electron from atom to overcome this attractive force.

Answer is: D) non-indigenous species.

Non-indigenous species or an introduced species is a species living outside its native area, but which has arrived there by human activity, either deliberate or accidental.

Kudzu (Japanese arrowroot) was introduced from Japan into the United States at the Japanese pavilion in the 1876 Centennial Exposition in Philadelphia.

The United States Forest Service estimated the rate of spreading of plant Kudzu to be 2500 acres per year.

Answer:

D. non-indigenous species.

Explanation:

Answer is: C. CaCl2.

Name of this chemical compounds is calcium chloride.

Calcium chloride is a inorganic salt with ionic bonds between calcium and chlorine.

It is a colorless crystalline solid at room temperature, highly soluble in water.

Calcium form cation with positive charge 2+ and chlorine form anion with negative charge 1-.

Electron configuration of calcium atom: ₂₀Ca 1s² 2s² 2p⁶ 3s² 3p⁶ 4s².  

Atomic number of calcium is 20, it means that it has 20 protons and 20 electrons, so atom of calcium is neutral.  

When calcium lost two electrons, it will have 20 protons (positive charge) and 18 electrons (negative charge), which means it has two protons more and it has +2 oxidation number.

Melting point of ethanol = -114°c  

Enthalpy of fusion = 5.02KJ/mol  

Specific heat of solid ethanol = 0.97J/gk  

specific heat of liquid ethanol = 2.3 j/gk.  

mass of ethanol = 25.0g

moles of ethanol = mass/Molar mass = 25.0/46.07 = 0.543 moles

step 1:

solid ethanol at -135 C changing to solid ethanol at -114 C

Q1 = mass x specific heat of solid ethanol x change in Temperature

 = 25.0 x 0.97 x [-114 - (-135)]  

  = 25.0 x 0.97 x [-114+135]  

 = 25.0 x 0.97 x 21  

Q1 = 509.25 J  

Step 2: solid ethanol at -114 C is changing to liquid ethanol at -114 C  

Q2 = moles x deltaHfusion  

= 0.543 x 5.02 KJ  

= 2.72586 x 1000 J  

Q2 = 2725.86 J  

Step 3: liquid ethanol at -114 C is changing to liquid ethanol at -50 C

Q3 = mass x specific heat of liquid ethanol x change in T  

= 25.0 x 2.3 x [-50 -(-114)]  

= 25.0 x 2.3 x [-50+114]  

= 25.0 x 2.3 x 64

Q3 = 3680J    

Total heat = Q1 + Q2 + Q3  

= 509.25 + 2725.86 + 3680  

= 6915.11 J      

Total heat = 6.915 KJ

Total heat required to convert 25.0g of solid ethanol at -135 C to liquid ethanol at -50 C is 6.9KJ.

To convert 25.0 g of solid ethanol at -135°C to liquid ethanol at -50°C, the heat required can be calculated through three main steps: heating solid ethanol to its melting point (-114°C), melting the solid ethanol to liquid form, and heating this liquid from -114°C to -50°C. With calculated heat for all three steps, the total heat required comes out to 6.913 kJ.

The calculation for this problem is divided into three parts: heating the solid ethanol from -135°C to its melting point (-114°C), melting the solid ethanol at -114°C to liquid ethanol, and finally heating the liquid ethanol from -114°C to -50°C.

Step 1 - Heating solid ethanol to its melting point: The heat required for this can be calculated using the formula q=m*CΔT, where m is the mass of the ethanol, C is the specific heat, and ΔT is the change in temperature. The calculation is q=(25.0 g)*(0.97 J/g°C)*(-114°--135°) which equals 507.75 J, or 0.50775 kJ.

Step 2 - Melting solid ethanol to liquid ethanol: We use the given enthalpy of fusion of ethanol 5.02 kJ/mol. However, first, we need to convert the mass of ethanol to moles, which gives us 0.542 moles. Therefore, the total heat for this step will be (0.542 mol)*(5.02 kJ/mol) = 2.72 kJ.

Step 3 - Heating liquid ethanol from -114°C to -50°C: We use the same q=m*CΔT formula, replacing C with the specific heat of liquid ethanol. The calculation becomes q=(25.0 g)*(2.3 J/g°C)*(-50°--114°) which gives us 3,685 J or 3.685 kJ.

In total, the heat required is the sum of the heat from all three steps: 0.50775 kJ + 2.72 kJ + 3.685 kJ = 6.913 kJ.

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Answer: Option (C) is the correct answer.

Explanation:

When the volume of a container is decreased and same number of gas molecules are present inside the container at the same temperature then it means that more number of gas molecules are spread per unit volume.

As earlier when the volume of container was more then the molecules were widely spread inside the container but on decreasing the volume of container, molecules come closer to each other and hence there will be increase in molecules per unit volume.  

Answer:

It is C

Explanation:

 The enthalpy  of  combustion  of magnesium  is -601.3  kj/mol

calculation

  ΔH = cΔT

   C( heat capacity) =5,760 j/°c

    ΔT = 0.570°c

 ΔH = 5760 j/°c  x 0.570 °c = 3283.2 j

convert 3283.2 j into Kj

1 kj = 1000 j

 kj ?  =3283.2 j

 by cross multiplication

={ (3283.2  j  x 1 kj) / 1000 j}  =3.2832 kj

Find the  moles of Mg

moles = mass÷ molar mass  

from periodic table the molar mass   of Mg = 24.3 g/mol

= 0.1326 g÷ 24.3 g/mol =0.00546 moles

find ΔH in KJ/mol

 =  3.2832 kj/ 0.00546 moles = 601.3 Kj/mol

since  heat  is released during combustion the ΔH  is  = - 601.3 kj/mol

Answer:

a) [tex]\text{no of moles}=\frac{\text{given mass}}{\text{Molecular mass}}[/tex]

[tex]\text{no of moles of sucrose}=\frac{1.202g}{342g/mol}=0.0035moles[/tex]

b) Moles of carbon in 1 mole of sucrose [tex]C_{12}H_{22}O_{11}[/tex]= 12 moles

Moles of carbon in  0.0035 moles of sucrose [tex]C_{12}H_{22}O_{11}=\frac{12}{1}\times 0.0035=0.042moles[/tex]

Moles of hydrogen in 1 mole of sucrose [tex]C_{12}H_{22}O_{11}[/tex]= 22 moles

Moles of hydrogen in  0.0035 moles of sucrose [tex]C_{12}H_{22}O_{11}=\frac{22}{1}\times 0.0035=0.077moles[/tex]

Moles of oxygen in 1 mole of sucrose [tex]C_12H_22O_11[/tex]= 11 moles

Moles of oxygen in  0.0035 moles of sucrose [tex]C_{12}H_{22}O_{11}=\frac{11}{1}\times 0.0035=0.042moles[/tex]

c)  1 mole of carbon contains [tex]=6.023\times 10^{23}atoms[/tex]

0.042 moles of carbon contain [tex]=\frac{6.023\times 10^{23}}{1}\times 0.042=0.25\times 10^{23}atoms[/tex]

1 mole of hydrogen contains [tex]=6.023\times 10^{23}atoms[/tex]

0.077 moles of hydrogen contain [tex]=\frac{6.023\times 10^{23}}{1}\times 0.077=0.46\times 10^{23}atoms[/tex]

1 mole of oxygen contains [tex]=6.023\times 10^{23}atoms[/tex]

0.042 moles of oxygen contain [tex]=\frac{6.023\times 10^{23}}{1}\times 0.042=0.25\times 10^{23}atoms[/tex]

The human “family tree” may be better described as a “family bush,” within which it is impossible to connect a full chronological series of species, leading to Homo sapiens, that experts can agree upon.

Final answer:

Bubbles in the ocean alter sound propagation by scattering and absorbing sound, which affects acoustic communication and the operation of sonar. Increased bubbles from thermal pollution can also decrease dissolved oxygen levels, impacting marine life.

Explanation:

The presence of bubbles in the global ocean can significantly affect sound propagation. Bubbles can scatter and absorb sound, altering its speed and direction. Consequently, this can influence acoustic communication and the effectiveness of sonar systems used by marine animals and humans for navigation, communication, and detection. For instance, dolphins rely on echolocation to navigate and hunt in the ocean, and bubbles can disrupt the transmission of these sound waves. Additionally, in areas with a high bubble content due to thermal pollution or natural gas seepage, sound may not travel as predictably, which could have navigational implications for sea life and technological systems.

Another aspect where bubbles can play a role is during thermal pollution events, where the solubility of gases in water decreases as the water temperature increases. This leads to the formation of more bubbles, which can reduce the amount of dissolved oxygen in the water, critically affecting marine life. Moreover, sonar technology, which relies heavily on the transmission of sound for detecting objects underwater, can be affected by the presence of bubbles as they change the medium through which sound waves travel. This can make the sonar less precise or reliable.

Final answer:

Copper wire is used in electrical wiring because its metallic bonding aids with conductivity of the material.

Explanation:

The metallic bonding between the atoms aids with the conductivity of the material.

Copper wire is used in electrical wiring because it has high electrical conductivity. Metallic bonding is responsible for the free flow of electrons in copper, allowing it to conduct electricity efficiently. This property makes copper an ideal material for conducting electric current in various appliances.

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).

Valence electrons have the greatest effect on the chemical properties of calcium

Electrons can move the shell up or down by releasing energy or absorbing energy

Excited electrons show higher electron transfer to the shell by absorbing energy

So it can be concluded that there are 2 conditions:

Ground state is the state of electrons filling skins with the lowest energy levels.

Excited state is the state of electrons which occupies a higher energy level

The state of excited electrons can be seen from the presence of electrons which do not fill the skin completely but fill the skin afterwards

Ca has atomic number 20 so the electron configuration is:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

This configuration can be said in Ground state conditions

Elemental properties can be determined by its valence electrons (electrons which fill electrons in the outer shell)

The valence electrons of an element indicate in what group and period the element is located in the periodic system so that its properties can be determined

The period of an element is determined from the valence shell (the biggest main quantum number (n) )

Groups of chemical elements are divided into two, namely:

Group A, occupying sub shell s and p

Group B, occupying sub shell d

If we look at valence electrons from Ca atoms then:

So that the Ca Atom is located in the alkaline earth group, together with beryllium (Be), magnesium (Mg), strontium (Sr), barium (Ba), and radium (Ra)

So the  chemical properties of calcium :

element X  

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electrons and atomic orbitals  

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The correct answer is D. Electromagnetic

Explanation:

Electron and protons are both subatomic particles that differ in their mass and other features including electromagnetic charges. Indeed, protons are positively charged, while electrons are negatively charged. This difference in electromagnetic charges causes electrons to be attracted to electrons, and vice versa due to electromagnetic forces as particles with different charges attract each other while those with the same charges repel each other. Thus, an electron and a proton attract each other as a result of electromagnetic forces.

Assuming total mass to be 100 g

Mass of C = 52.93 g

=> Moles of C = [tex]52.93 g *\frac{1 mol}{12gC} =4.41 mol C[/tex]

Mass of H = 5.92 g

=> Moles of H=[tex]5.92g*\frac{1mol}{1.01g}=5.86molH[/tex]

Mass of N = 41.15 g

=>Moles of N=[tex]41.15g*\frac{1 mol}{14 g}=2.94mol N[/tex]

Simplest mole ratio of the atoms in the compound:

[tex]C_{\frac{4.41mol}{2.94mol} } H_{\frac{5.86mol}{2.94mol} }N_{\frac{2.94mol}{2.94mol} } =C_{1.5}H_{2}N_{1} or(C_{1.5}H_{2}N_{1})_{2}=>C_{3}H_{4}N_{2}[/tex]

Empirical formula mass=[tex](3*12)+(4*1.01)+(2*14)=68.04g[/tex]

Multiple n = [tex]\frac{204.2}{68.04}=3[/tex]

Molecular formula= [tex](Empirical formula)_{n} =(C_{3}H_{4}N_{2})_{3}=C_{9}H_{12}N_{6}[/tex]

Final answer:

The empirical formula of triethylenemelamine is determined to be C₃H₄N₂ based on the given percentage composition. By comparing the molecular mass of triethylenemelamine to the mass of the empirical formula unit, the molecular formula is found to be C₆H₈N₄.

Explanation:

To determine the empirical formula and molecular formula of triethylenemelamine based on its percent composition (52.93% carbon, 5.92% hydrogen, 41.15% nitrogen) and molecular mass (204.2 g/mol), follow these steps:

Calculate the moles of each element based on 100 g of the compound.
For Carbon: (52.93 g / 12.01 g/mol) = 4.41 moles
For Hydrogen: (5.92 g / 1.008 g/mol) = 5.87 moles
For Nitrogen: (41.15 g / 14.01 g/mol) = 2.94 moles

Determine the simplest whole number ratio of the elements by dividing by the smallest number of moles, which in this case is 2.94 moles (N). This gives:
C: 4.41 / 2.94 ≈ 1.5
H: 5.87 / 2.94 ≈ 2
N: 2.94 / 2.94 = 1

Since the ratio needs to be in whole numbers, multiply each by 2 to get C₃H₄N₂ as the empirical formula.

To find the molecular formula, divide the molecular mass of triethylenemelamine (204.2 g/mol) by the mass of the empirical formula unit (C₃H₄N₂ = 3(12.01) + 4(1.008) + 2(14.01) ≈ 84.1 g/mol), getting approximately 2.43. Since molecular formulas must be whole numbers, this indicates the empirical formula must be multiplied by 2, giving C₆H₈N₄ as the molecular formula of triethylenemelamine.

The correct answer is option C, that is, the turtles will no longer be found in Georgia.  

Due to the presence of protected dunes and temperate climate appropriate for nesting activities, the barrier island beaches of Georgia host an average of 1000 sea turtles nests in a year.  

However, the main danger to sea turtles in Georgia is the damage of their eggs and nests and offshore mortalities related to commercial longline fishing or shrimping activities. With the development going on in the coastal regions where the turtles thrive, a time will come when one will no longer witness any turtle along the coast of Georgia.  

Answer:

C

Explanation:

The turtles will no longer be found in Georgia.

Silicon tetrachloride (SiH4) is a covalent tetrahedral molecule with a trigonal pyramidal shape. It is nonpolar and has a low boiling point of 57 °C.

Silicon tetrachloride (SiH4) is a covalent tetrahedral molecule with a trigonal pyramidal shape. The Lewis structure for SiH4 would show the silicon atom in the center with four chlorine atoms bonded to it. Each chlorine atom would have a lone pair of electrons, causing the molecule to have a trigonal pyramidal shape.

The electronegativity values of silicon and chlorine are 1.9 and 3.2 respectively, indicating a polar covalent bond between silicon and chlorine. However, due to the symmetry of the molecule, the dipole moments cancel each other out, resulting in a nonpolar molecule. Silicon tetrachloride is a colorless liquid with a low boiling point of 57 °C.

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Silicon tetrahydride (SiH4) is a nonpolar molecule with a tetrahedral shape due to the central silicon atom being sp³ hybridized. Even though Si-H bonds are polar, the symmetry of the molecule results in a nonpolar overall molecule.

The bond polarities of SiH4 are Nonpolar. SiH4, or Silicon tetrahydride, is a covalent molecule with tetrahedral structure, in which Silicon (Si) forms four single bonds with four Hydrogen (H) atoms. Central Silicon atom is sp³ hybridized, which results in a Tetrahedral molecular shape. Even though the Si-H bonds are polar because of the difference in electronegativities of Si and H, the bond dipoles cancel each other because of the molecule's symmetry, making the whole molecule Nonpolar.

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Answer:

The correct answer is option A.

Explanation:

Schrodinger proposed the mechanic model of atom in which he defined the location of electrons inside an atom by electron cloud in 3-d space. And in order to locate them he introduced the concept of quantum numbers.

Where as photons are the discrete  packet or bundle of energy related to electromagnetic radiations.

the molecularity of C12H22O11 is = 12x12+22x1+16x11 = 342 g/mol

molarity (M) = moles / V. solution

moles = mass / 342 = 15,6/342 = 0,0456 moles

=> molarity (M) = 0,0456/0,0655 = 0,696 M

To find the molarity of a solution, convert the mass of the solute to moles, convert the volume of the solution to liters, and divide the number of moles by the volume in liters. The molarity of a solution containing 15.6 g of sucrose in 65.5 mL of solution is 0.696 M.

The molarity (M) of a solution is calculated using the formula M = mol/L, where mol represents the number of moles of the solute and L represents the volume of the solution in liters. First, we must convert the mass of sucrose to moles. Sucrose, C12H22O11, has a molar mass of approximately 342.3 g/mol. Therefore, 15.6 g / 342.3 g/mol = 0.0456 mol. Next, we convert the volume of the solution to liters: 65.5 mL = 0.0655 L. Finally, we can calculate the molarity of the solution: M = 0.0456 mol / 0.0655 L = 0.696 M. Therefore, the correct answer is 0.696 M.

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The simplest answer and the correct one is saturated. You can try this at home to see what it looks like. Take a  glass and fill it to the 1/2 full mark. Make sure the water is on the coolish side. Start putting measured amounts of salt in the water. Do this until you see salt on the bottom of the glass. The solution is now saturated.

Empty the glass. Put the same amount of water in the glass but make it much  warmer. Put the same amount of salt in the glass. It should not be saturated -- that is there should be no salt on the bottom.

So temperature determines saturation. But more important, you should get an idea of what saturation is.

Answer:

Iron (II) ion.

Explanation:

So, the right choice is:  iron (II) ion.

Answer:

The correct answer is the option: Iron (II) ion.

Explanation:

Hello! Let's solve this!

El Hierro (Fe) has two valence numbers. Fe + 2 and Fe +3.

The +2 and +3 indicate that iron lost two or three electrons respectively.

In this case the ion is Fe + 2, this cation is called the Iron (II) ion

We conclude that the correct answer is the option: Iron (II) ion.

In order to find the mass (in grams) of an element, you just need to multiply the no. of moles given by the atomic mass of the element, which can be found in a periodic table.

mass of 15.0 moles of N= 15.0 x 14.0 = 210g

mass of 5.0 moles of Zn= 5.0 x 65.4 = 327g

mass of 20.0 moles of H= 20.0 x 1.0 = 20g

mass of 1.0 moles of Pb= 1.0 x 207.2 = 207.2g

Therefore, since 327g is the greatest mass out of the 4 options, the answer is 5.0 moles of Zn.

The quick answer is B

3 moles

A mole has an alternate definition of 6.02 * 10^23 particles or atoms (in this case) that make it up.

A is possible, but it is not the question.

C is possible, but it is not the question.

I've never directly seen D before. It is used with gases (indirectly).

Fe2O3(s) + 3CO(g) -----> 3CO2(g) + 2Fe(s)

mass of iron = 198.5 g of iron

atomic mass of iron = 55.845g/mol

moles of iron = mass/Atomic mass

= 198.5g/55.845  

= 3.5545 moles Fe

moles of carbon monoxide

= 3.5545 moles Fe x    3 moles CO    

                                       2 moles Fe

= 5.3317 moles CO

molar mass of CO = 12.01 + 16 = 28.01g/mol

mass of carbon monoxide reacted

= moles x molar mass

= 5.3317 x 28.01

= 149.34g

grams of carbon monoxide needed to react with an excess of iron(II)oxide to produce 198.5g of iron is     149.34g CO

Final answer:

The discovery and usage of the periodic table has benefited society by enabling easy communication of chemical discoveries, predicting and discovering new elements, and driving technological innovations.

Explanation:

The discovery and usage of the periodic table has benefited society in several ways:

The International System of Units (S.I.) is the modern form of the metric system, and is the most widely used system of measurement.

It comprises a coherent system of units of measurement built

- on seven base units, which are

(the ampere, kelvin, second, metre, kilogram, candela, mole)

- a set of twenty prefixes to the unit names and unit symbols that may be used when specifying multiples and fractions of the units.

The system also specifies names for 22 derived units, such as lumen and watt, for other common physical quantities.

So, the mole not should be .... is a base unit in the SI system

Yes, the mole should be considered as a base unit in the SI unit.

A mole is defined as the physical properties of the real object, the carbon atom. Therefore, it is a base unit.

Thus, the mole is considered as a base unit in the SI system, because it defined as physical properties of real objects.

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I would have to say B. Linear

I hope this helps!

Cheers, July.

Answer : The correct option is, (B) Linear

Explanation :

Formula used  :

[tex]\text{Number of electrons}=\frac{1}{2}[V+N-C+A][/tex]

where,

V = number of valence electrons present in central atom

N = number of monovalent atoms bonded to central atom

C = charge of cation

A = charge of anion

Now we have to determine the hybridization of the [tex]BeH_2[/tex]  molecules.

[tex]\text{Number of electrons}=\frac{1}{2}\times [2+2]=2[/tex]

The number of electrons is 2 that means the hybridization will be [tex]sp[/tex] and the electronic geometry of the molecule will be linear.

The three-dimensional shape of the molecule with the Lewis structure are shown below.

In a pack of CaCl2 and H2O, hydrolysis of Ca+2 will occur

This will result in formation of Ca(OH)2.

The reaction is exothermic in nature

so the balanced thermo-chemical equation will be

CaCl2(aq) + H2O (l)  ---> Ca(OH)2   + 2HCl + Heat

In a pack of NH4NO3 and H2O hydrolysis of NH4+ will occur as

NH4NO3 (aq)  + H2O(l)  + Heat ---> NH4OH(aq)  + HNO3 (aq)

It is an endothermic reaction

The correct answer is reactants 2Na and 2H₂O and products 2NaOH and 1H₂.  

The given unbalanced chemical equation is:  

Na (s) + H2O (l) → NaOH (aq) + H₂ (g)

From the equation, it can be seen that there are three atoms of hydrogen on the products side, however, only two on the reactant's side. So, in order to balance the equation, one needs to multiply the sodium hydroxide by 2 to get a total of 4 atoms of hydrogen on the product's side.  

This will enable one to readily double the number of molecules of water to get 4 atoms of hydrogen on the reactants side, and then balance the atoms of sodium by multiplying the sodium metal by 2. The balanced equation obtained is:  

2Na (s) + 2H₂O (l) → 2NaOH (aq) + H₂ (g)

In the given chemical reaction, Reactants: 2Na and 2H₂O and Products: 2NaOH and 1H₂. Therefore, option D is correct.

In the balanced equation, the coefficients indicates the relative number of moles of each substance involved in the reaction. The balanced equation for the reaction between sodium (Na) and water (H₂O) to produce sodium hydroxide (NaOH) and hydrogen gas (H₂) is: 2Na + 2H₂O → 2NaOH + H₂

This balanced equation shows that 2 moles of sodium reacts with 2 moles of water to produce 2 moles of sodium hydroxide and 1 mole of hydrogen gas.

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FeCO3  ==> Fe + produsi minoritari.

m Fe impur= 700 kg

puritatea (p) = masa pura (mp)/ masa impura (mi) x 100

mp= p x mi / 100 sau mp = p/100 x mi => mp Fe = 90/100 x 700 = 630 kg Fe pur.

M FeCO3= 115.85 kg/kmol

115.85 kg FeCO3 .... 55.85 kg Fe

     x kg FeCO3  ........630 kg Fe

x= 630 * 115.85 /55.85 = 1306.81 kg FeCO3 (mp in formula puritatii)

p=mp/mi x 100

mi FeCO3 = 1500 kg

mp FeCO3=1306.81 kg

p=1306.81 / 1500 x 100 = 87.12% puritate Siderit