The correct answer is option B, that is, add 1.46 grams of NaCl to 250 milliliters of H₂O.
First there is a need to find the moles of NaCl in 250 ml of 0.10 M NaCl,
Moles of NaCl = molarity × volume = 0.10 M × (250/1000L) = 0.025 mol
The corresponding mass of NaCl is,
Mass of NaCl = moles × molar mass = 0.025 mol × 58.5 g/mol = 1.46 g
Thus, there is a need to dissolve 1.46 grams of NaCl solid into 50 ml of H₂O and dilute to 250 ml.
The most appropriate procedure to prepare a 0.10 M NaCl solution with a volume of 250.0 mL is to dissolve 1.46 g of NaCl in 50 mL of water and dilute to 250 mL.
Explanation:The most appropriate procedure to prepare a 0.10 M NaCl solution with a volume of 250.0 mL is option D. Dissolve 1.46 g of NaCl in 50 mL of H2O and dilute to 250 mL.
To determine the amount of NaCl needed, we can use the molarity formula:
Molarity = (moles of solute) / (volume of solution in liters)
Using the given molarity of 0.10 M and the volume of 0.250 L (250 mL), we can rearrange the formula to solve for moles of solute:
moles of solute = molarity * volume of solution
Substituting the values, we get:
moles of solute = (0.10 M) * (0.250 L) = 0.025 moles
And finally, we can calculate the mass of NaCl needed using the molar mass:
mass = moles of solute * molar mass
mass = (0.025 moles) * (58.4 g/mol) = 1.46 g
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When uranium-238 is transformed into thorium-234, it is represented by a balanced equation. What is missing from the equation of U-238 undergoing radioactive decay?
The unstable atomic nucleus of Uranium-238 emits ionizing particles and loses energy in order to achieve a stable state. This process is called the Radioactive decay. This isotope undergoes Alpha decay by emitting Alpha rays. It has a decay energy of 4.267 MeV.
Final answer:
The decay of uranium-238 to thorium-234 is represented by a nuclear equation that must balance in terms of both mass numbers and atomic numbers, owing to conservation laws. The emission of an alpha particle during the decay of U-238 results in Th-234, with the mass number decreasing by 4 and the atomic number by 2.
Explanation:
When uranium-238 decays to form thorium-234, this is represented by a nuclear equation owing to the transformation occurring within an atomic nucleus. According to conservation of mass and atomic numbers, the nuclear equation must balance, both in terms of the mass numbers and the atomic numbers. Considering uranium has an atomic number of 92 (Z = 92) and a mass number of 238, when it loses 2 protons and 2 neutrons which occurs during the emission of an alpha particle (He), we are left with thorium-234 (Th).
The balanced nuclear equation for this decay process is:
^238_92U → ^4_2He + ^234_90Th
This shows the loss of an alpha particle from uranium-238 which results in thorium-234. The sum of the mass numbers and atomic numbers on the reactant side must equal the sum on the product side, hence confirming that the equation is correctly balanced. The loss of four nuclear particles (2 protons and 2 neutrons) is accounted for by the alpha particle, reducing the mass number by 4 from 238 to 234, and dropping the atomic number from 92 to 90 which identifies the new element as thorium. Furthermore, this decay sequence continues as thorium-234 decays via beta emission to form protactinium-234, which then decays to uranium-234.
How many electrons does (Al) have to give up to achieve a noble gas?
Aluminium has 3 valance electrons in its outer shell. This means that it would need to give up 3 electrons to achieve a full octet.
Calculate the kinetic energy, in J/mole, of 1.00 mole of gaseous water molecules at room temperature (25.0ºC).
The kinetic energy per mol of gaseous water molecules at 25°C is approximately 3.72 KJ/mol.
Explanation:The kinetic energy of gaseous molecules can indeed be calculated using the equation KE = (3/2) * k * T, where KE represents kinetic energy, k is the Boltzmann constant (1.381 x 10^-23 J/K), and T is the temperature in Kelvin. To perform this calculation for gaseous water molecules at 25°C, you correctly converted the temperature from Celsius to Kelvin (25°C = 298.15 K).
So, KE = (3/2) * (1.381 x 10^-23 J/K) * (298.15 K) = 6.18 x 10^-21 J per molecule.
To determine the kinetic energy per mole of gaseous water molecules, you can indeed multiply this value by Avogadro's number (6.022 x 10^23 molecules/mol):
(6.18 x 10^-21 J/molecule) * (6.022 x 10^23 molecules/mol) ≈ 3.72 kJ/mol.
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The kinetic energy of 1.00 mole of gaseous water molecules at room temperature can be calculated using the equation KE = (3/2)RT, assuming the molecules are ideal. The temperature needs to be converted to Kelvin before plugging it into the equation.
Explanation:The kinetic energy of 1.00 mole of gaseous water molecules at room temperature can be calculated using the equation for translational kinetic energy. We can obtain the average kinetic energy of a molecule by dividing out the number of molecules and multiplying by 3/2. Assuming the gaseous water molecules are ideal, we can use the equation KE = (3/2)RT to calculate the kinetic energy, where R is the gas constant and T is the temperature in Kelvin.
Using the given temperature of 25.0ºC, we need to convert it to Kelvin by adding 273.15 to the Celsius temperature. So, 25.0ºC = 25.0 + 273.15 = 298.15 K. Assuming R = 8.314 J/mol·K, we can calculate the kinetic energy as follows:
KE = (3/2)(8.314 J/mol·K)(298.15 K) = 18659.6 J/mol
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How does the energy of independent atoms compare the energy of bonded atoms
Independent atoms have high potential energy,and they are highly unstable.
And when they form bonds their potential energy decreases and they become stable.
Hence bonded atoms are stable and have relatively low potential energy than independent atoms.
Elements in the first column of the periodic table are known as alkali metals. What do these elements have in common when ionized?
The alkali metals takes column 1 A of the periodic table.some of them are hydrogen, potassium,lithium etc. The elements gets into their ionic +1 form because they easily lose their one electron in the outermost shell.This one electron is the outermost layer of electrons is responsible for the various properties of alkali metals.
Alkali metals all form cations with a +1 charge upon ionization due to the easy loss of their single valence electron. This is due to their large atomic radii and low first ionization energies.
The elements in the first column of the periodic table, known as alkali metals, include lithium, sodium, potassium, rubidium, cesium, and francium. These elements are characterized by having the largest atomic radii in their respective periods and the lowest first ionization energies, which makes it easy for them to lose their single valence electron. When ionized, alkali metals all form stable cations with a +1 charge.
The periodic table can thus be used as a tool to predict the charge of ions based on an element's location. For instance, all alkali metal ions have a +1 charge, and the convention is to write the number and then the sign, like Li+ or Na+, illustrating that each alkali metal cation has one positive charge.
What is the pOH of a 0.00037 M solution of barium hydroxide
Answer: pOH = 3.13
Ba(OH)2 is a very basic substance. The general formula for pOH is - log(OH)
Barium Hydroxide produces 2 moles of OH for every mole of Ba(OH)2 present in the solution.
0.00037 M = 3.7 * 10^-4 Ba(OH)2 will produce 2 *0.00037 M of OH-
OH- = 2* 0.00037 = 0.00074
pOH = - log(0.00074) = 3.13
Answer:
3.13
Explanation:
Economics is a social science that focuses on
Answer:
Economics is a social science that focuses on the study of human activity and behavior and its relationship with the administration of the processes of extraction, production, exchange, distribution and consumption of goods and services.
Explanation:
Economics is a social science that studies the processes of extraction, production, exchange, distribution and consumption of goods and services. In other words, economics is a social science that studies how to manage the resources available to meet human needs, also studying the behavior and actions of human beings, their interaction with certain events and the effect they produce on their environment.
In this way the economy tells us how societies use scarce resources to produce goods with value, and how they make the distribution of wealth among individuals.
In summary, economics is a social science that focuses on the study of human activity and behavior and its relationship with the administration of the processes of extraction, production, exchange, distribution and consumption of goods and services.
Economics is a social science concerned with decision-making in the context of scarcity, analyzing individual to societal level choices regarding resource allocation.
Explanation:Economics is a social science that focuses on how humans make decisions in the face of scarcity. It explores various types of decisions, including individual, family, business, and societal choices, and the motivating factors behind these decisions. Due to the scarcity of goods, services, and resources like labor, tools, land, and raw materials, economics scrutinizes how these limited resources are allocated to meet the infinite wants of people. Moreover, time is considered an ultimate scarce resource, since we all have a finite amount of it to use each day.
Economics can be broadly categorized into two main areas: microeconomics, which studies the behavior and decisions of individual units such as households and firms, and macroeconomics, which examines the economic activity of an entire nation or the global economy. As a discipline, it uses a scientific approach to analyze and understand the financial and resource allocation decisions and their impacts on society.
Which pair of elements would form a nonpolar covalent bond?
A.bismuth and sulfur
B.carbon and oxygen
C.nitrogen and oxygen
D.silicon and phosphoro
Answer is: D.silicon and phosphorus.
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.
A) Δχ(Bi-S) = 2.5 - 2.0 = 0.5; polar covalent.
B) Δχ(C-O) = 3.5 - 2.5 = 1.0; polar covalent.
C) Δχ(N-O) = 3.5 - 3 = 0.5; polar covalent.
D) Δχ(Si-P) = 2.2 - 1.9= 0.3; nonpolar covalent.
Scientific theories are explanations for naturally occurring events or phenomena. Although scientific theories require extensive observations and experimentation, they can change over time as new evidence is discovered. Scientific laws are principles that are also based on extensive observations and experimentation. Although scientific theories can develop into laws, a theory can only be declared a law if it is proven to be without exception under certain stated conditions. Which of the following is true regarding scientific theories,laws, and knowledge?
A.
New scientific knowledge is gained by memorizing scientific theories and laws.
B.
Scientific theories can lead to scientific knowledge, but scientific theories are not related to scientific knowledge.
C.
Scientific knowledge must be proven by both scientific theories and laws.
D.
Scientific theories and laws develop from the acquisition of scientific knowledge.
Answer: D. Scientific theories and laws develop from the acquisition of scientific knowledge.
Explanation:
The scientific knowledge is acquired by using the detail knowledge of scientific methodology which is used in both scientific theories and laws. The scientific methodology includes the observing things, making hypothesis on the basis of observation, testing the hypothesis, performing the experiment and concluding the results. The results obtain will contribute to new innovation and research which will further contribute to the scientific knowledge.
what will be the new volume of a 250mL sample of gas at 300 k and 1 atm if heated to 350 k at 1 atm law use:
Answer:
292 mL
Step-by-step explanation:
The pressure is constant.
The only variables are volume and temperature, so we can use Charles’ Law.
V₁/T₁ = V₂/T₂ Multiply each side by T₂
V₂ = V₁ × T₂/T₁
V₁ = 250 mL; T₁ = 300 K
V₂ = ?; T₂ = 350 K
V₂ = 250 × 350/300
V₂ = 292 mL
In need of help!!!!
In Nuuk, what is the average net change in temperature, from the high to the low, in January? the average high is -6 celsius, and average low is -10 celsius.
Answer is: the average net change in temperature is 4°C.
the average net change = the average high - the average low.
the average net change = -6°C - (-10°C).
the average net change = 4°C.
Temperature is the intensity of heat present in a substance and a thermometer is a device that measures temperature or a temperature gradient.
The Celsius scale was based on 0°C for the freezing point of water and 100°C for the boiling point of water at 1 atm pressure.
The average net change in temperature in Nuuk in January, from the high to the low, is 4 degrees Celsius. This is determined by subtracting the average low temperature from the average high temperature.
Explanation:In Nuuk, the average net change in temperature in January from high to low is calculated by subtracting the average low temperature from the average high temperature. Therefore, with an average high of -6 Celsius and an average low of -10 Celsius, the net change is 4 degrees Celsius. This is a routine method for determining the daily temperature range in a specific location, particularly useful in meteorology and climatology studies.
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valance refers to the total number of electrons that exist in the orbitals that occupy the outermost energy level of an atom
valance refers to the total number of electrons that exist in the orbitals that occupy the outermost energy level of an atom. you pretty much got it!
The reaction CO2(g) → C(s) + O2(g) is a decomposition reaction.
True
False
The reaction CO₂(g) → C(s) +O₂(g) is a decomposition reaction is true
Explanation
A Decomposition reaction is a reaction in which involve breaking down a compound into two or more simpler substances.
The reaction above is a decomposition reaction since CO₂ molecule is broken down into C (an element) and O₂ (a molecule).
Answer:
True
Explanation:
How to do this question?
Like the diagram we can see the the products of reaction are obtained with a amount of heat under the heat of reactants... so the reaction is exothermic and the Ea = E* - Eproducts = 100 - 40 = 60 kJ
list 10 chemical reactions that have benefited your life today. Include the reasons you think each was indeed a chemical reaction and not just a physical change. Thank about processes in your body, processes in the atmosphere, or chemical reaction later that may be involved with any materials or products you have used.
1) The overall balanced photosynthesis reaction:
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
Plants convert solar energy into the chemical energy of sugars (food).
2) Chemical reaction of cellular respiration:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O.
Organic carbon (glucose) is transformed into inorganic carbon (carbon dioxide) that goes into atmosphere.
3) Gasoline combustion:
C₈H₁₈ + 25/2O₂ → 8CO₂ + 9H₂O.
Gasoline is a mixture of many different hydrocarbons: alkanes (paraffins), cycloalkanes and alkenes (olefins).
Gasoline is being burn.
4) Balanced chemical reaction of forming rust: 4Fe + 3O₂ → 2Fe₂O₃.
Forming rust usually last for few months and iron changing in another substance with different properties.
5) An electrochemical cell (voltaic or galvanic cell) is generating electrical energy from chemical reactions.
In galvanic cell, specie (for example zinc and zinc cations) from one half-cell, lose electrons (oxidation) and species from the other half-cell (for example copper and copper cations) gain electrons (reduction).
Oxidation on the zinc anode: Zn(s) → Zn²⁺(aq) + 2e⁻.
Reduction on the copper cathode: Cu²⁺(aq) + 2e⁻ → Cu(s).
Copper is forming from the solution, that is chemical change.
6) Balanced chemical reaction: CaO + H₂O → Ca(OH)₂.
Making limewater (diluted solution of calcium hydroxide).
7) Neutralization is reaction in which an acid and a base react quantitatively with each other. In this reaction, there are no acids and bases, only salts.
Balanced chemical reaction of vinegar and antacid:
2CH₃COOH(aq) + Mg(OH)₂(aq) → (CH₃COO)₂Mg(s) + 2H₂O(l).
Precipation is formed.
8) Balanced chemical reaction of magnesium and hydrochloric acid:
MgO + 2HCl → MgCl₂ + H₂O(g).
Acid dissolves metal oxides.
9) Chemical reaction of silver in air:
4Ag + 2H₂S + O₂ → 2Ag₂S (tarnish) + 2H₂O.
Silver change color in the air.
10) Forming of patina: 2CuO + CO₂ + H₂O → Cu₂CO₃(OH)₂.
Brass (copper) change color to green.
For a particular reaction, ΔH° is 34.2 kJ and ΔS is 99.2 J/K. Assuming these values change very little with temperature, over what temperature range is the reaction spontaneous in the forward direction?
Over 344.76 K the forward reaction will be spontaneous
calculation
ΔG = ΔH° -TΔs
if ΔG =0
therefore 0 =ΔH°-TΔs
ΔH° = TΔs
divide both side by Δs
T = ΔH°/Δs
convert 34.2 kj into j
that is 1 kj = 1000 j
34.2 kj =? j
by cross multiplication
=[34.2 kj x 1000j / 1 kj] = 34200 j
T is therefore = 34200 j÷99.2 j/k =344.76 k
if T is greater than 344.76 k the forward reaction will be spontaneous
The calculation of temperature is done as follows:
T = ΔH°/ΔS°
= 34.2 kJ/mol / 99.2 × 10⁻³ kJ/molK
= 345 K
Since, ΔS° and ΔH° comes out to be positive for the given reaction. Hence, the given reaction is spontaneous at higher temperature and non spontaneous at lower temperature. Thus, it can be said that above 345 K, the given reaction will become spontaneous.
calculate the hydroxide ion concentration [OH-] for a solution with a pH of 6.10
There are different formula you need to keep in mind when solving for [OH-]
Given that pH = 6.10
pH + pOH = 14
6.10 + pOH = 14
pOH = 7.9
[OH-] = 10^(-pOH)
[OH-] = 10^(-7.9)
[OH-] = 0.000000013
[OH-] = 1.3 x 10^-8
The hydroxide ion concentration in an aqueous solution is equal to 10⁻⁸M.
What is the pOH?pOH can be determined by taking the negative logarithm of the hydroxide ions concentration in the given aqueous solution.
Mathematically, pOH can be expressed in the form of hydroxide ion concentration as follows:
pOH = - log [ OH⁻]
and, [tex]pH + pOH = 14[/tex] ..............(1)
where [OH⁻] is the hydroxide ions concentration present in an aqueous solution.
Given, the value of pH of the solution containing hydroxide ions:
pH = 6.10
Substitute the value of the pH in equation (1):
pH - log [OH⁻] = 14
6.10 - log [OH⁻] = 14
log [OH⁻] = - 7.9
[OH⁻] = [tex]10 ^{-7.9}[/tex]
[OH⁻] ≈ 10⁻⁸ M
Therefore, the concentration of the hydroxide ions in an aqueous solution is equal to 10⁻⁸ M.
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When you push downward on Earth to make a pole vault, does Earth exert an equal source on the pole?
Which of the following is an example of a double-replacement reaction? A. 3K + AlCl3à 3KCl + Al B. KOH + HBr à KBr + H2O C. CH4 + 2O2à CO2 + 2H2O D. Cu + 2H2SO4à CuSO4 + SO2 + 2H2O
B is a double replacement reaction where OH and Br switch places.
If atoms of a halogen nonmetal (Group 17) gains one electron, the atoms the have __.
Hm, this could be more than one option, but gaining electrons makes a negative charge, so
If atoms of a halogen nonmetal (Group 17) gains one electron, the atoms the have "a negative one charge".
Answer:
Atoms of a halogen nonmetal gain one electron, the atom has a -1 charge.
Explanation:
The halogen non-metals of Group 17 have 7 valence electrons in their valence shell.
For an element to complete its octet and reach the stable configuration, 8 electrons are required. On gaining an electron the must be an impartment of a negative charge onto the element.
For group 17 elements to complete the octet they need to withdraw one atom. So the charge must be 1.
Since they are accepting the electron, they impart a negative charge.
So, group 17 halogen metals on gaining 1 electron have a -1 charge.
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If an object starts at rest and moves 16 m north along a straight line for two seconds what is its average velocity
The answer would be 8 m/s. To find the answer you divide distance by time which is 16 divided by 2.
Covalent solutes are considered non-electrolytes. What does this mean for the conductivity of the solution?
Answer: The conductivity of the solution is very low or near zero
Explanation:
Covalent compounds do not have free electrons and do not dissociate into ions. Ions are the charge carriers in solution and are responsible for the conductivity of electrolyte solutions. Non-electrolytes do not dissociate into ions hence they do not conduct electricity in solution. The conductivity is very low due to the absence of ions making the solution unable to conduct electricity.
which of the following atoms would be most likely to have an unstable nucleus?
3
is the answer i do believe
how did jonesy die?
he got shot while shielding a child
please help ! pls ! do today
Before I answer, I wanna say that my school uses that EXACT same program! Is it called USATestPrep? Tell me if so!
ANYWAY, the answers are:
DNA:
Base pairing allows this molecule to act as a templateGene:
Codes for a specific proteinProtein:
Made of amino acidsChromosome:
DNA is packaged into these compact unitsOccur in pairs in body cellsA molecule of pentane is made of 5 carbon atoms and 12 hydrogen atoms. A collection of pentane molecules has 3.01 x 10^24 carbon atoms. How many hydrogen atoms are in the collection?
A truck drives at an average speed of 100 km/h. How far can it travel in 30 minutes? A. 30 km B. 50 km C. 80 km D. 100 km
B. 50 km
Seeing as the truck would travel approximately 100 kilometers in an hour, or 60 minutes, it would travel half that distance in half the time--50 kilometers in a half hour, or 30 minutes.
Answer:B
Explanation:
Speed= distance/time
Distance= speed× time
Speed= 100km/hr
Time= 30 mins or 0.5 hours
Therefore: distance= 100×0.5= 50Km
Note:60 minutes make one hour!
Why does food wrapped in aluminum foil keep warm for a long time? A) Aluminum foil is an insulator and prevents heat loss by conduction. B) Aluminum foil forms an air-tight seal and prevents heat loss by convection. C) The silver surface of the foil reflects heat in and prevents heat loss by radiation. D) The silver surface of the foil absorbs heat from the surroundings and keeps the food warm.
The answer is A or D
the correct answer is c.
Name the isotope used as a fuel and give its symbol , including nucleon number.
fast please
The isotope which is used as fuel in nuclear power generators is uranium - 235. THe nuclear symbol is [tex]\rm_{92}^{235}U[/tex].
What are isotopes?Isotopes are atoms of same element with different mass number. They may differ in the physical and chemical properties also. Not all isotopes of an atom are stable. Some of them are radioactive and are unstable.
Uranium is 92nd element in periodic table. It is a radioactive element placed in among the actinides in f- block elements. Uranium undergo alpha or beta decay producing more stable nuclei with different composition.
Nuclear decay evolves energy and thus radioactive elements such as U are used as fuel in power generation plants.
An isotope is represented by the chemical symbol with the atomic number as subscript and mass number as superscript.The isotopic symbol of U is [tex]\rm_{92}^{235}U[/tex]. The mass number is 235. and the number of protons and neutrons are 92 and 143 respectively.
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Which of these has the most mass? A. a laser beam B. a rocket in space C. a pitched baseball D. a stationary baseball
the answer is ( . a rocket in space )
Answer:
The correct option is B
Explanation:
The mass of an object is the amount of substances/molecules present in that object. The mass of an object remains the same anywhere regardless of gravity. In space, where there is no gravity, the mass of a rocket remains the same but the weight will be different because of zero gravity which means there will be no force of gravity pulling the rocket towards itself.
Hence, weight can be calculated as
Mass of an object (in kg) × gravitional field strength (in N/kg)
From the above formula, it can be deduced that weight is dependent on mass and gravity but mass is not (when you make mass the subject of the formula).