In the nucleus you will find most of the __________ of an atom. a. mass
b. charge
c. electrons
d. protons and neutrons

 To solve this we assume that the gas is an ideal gas. Then, we can use the ideal gas equation which is expressed as PV = nRT. At a constant temperature and number of moles of the gas the product of PV is equal to some constant. At another set of condition of temperature, the constant is still the same. Calculations are as follows:

P1V1 =P2V2

V2 = P1 x V1 / P2

V2 = 42.0 x 12.5 / 75.0

V2 = 7.0 L

Answer:

7.00 L

Explanation:

The only thing that varies between the two situations is pressure and volume.

we have the ideal gas equation

We know that n = moles of substance remain constant, also the temperature and n corresponding to the ideal gas constant

Situation N1

Situation N2

As nrT are equal both times, therefore we can match this term in both equations

We equate both equations

Final answer:

The atom X has 15 electrons.

Explanation:

The number of electrons in an atom is equal to the number of protons. Since the atom X has 15 protons, it also has 15 electrons.

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Answer:

D. The melting of ice

Explanation:

An endothermic reaction ABSORBS heat from its surroundings, it does NOT give heat off into its surroundings.

so...

When a match burns, it gives of heat. So A is incorrect.

When water goes from a vapor into a liquid, the water molecules loose kinetic energy, they do not gain it. And since temperature is the measure of the average kinetic energy in a substance, the water vapor looses heat. If the process was endothermic, it would be gaining heat. So B is incorrect.

When propane gas combusts, the explosion lets off heat into its surroundings, it does not absorb heat. So C is incorrect.

Here's what happens when something melts: the molecules inside the substance receive more and more kinetic energy, until the substance's molecules have enough kinetic energy to vibrate and wiggle past each other, breaking their structure. When ice melts it is receiving kinetic energy from its surroundings, and again, since temperature is the measure of the average kinetic energy in a substance, the process is absorbing heat. Q.E.D.,

D is the correct answer.

Answer:

(NH4)2CO3(s) → 2 NH3(g) + CO2(g) + H2O(g)

Explanation:

The balanced equation can be written when we know the chemical formula of each reactants and products of the reaction.

Ammonium carbonate = (NH4)2CO3(s)

Ammonia = NH3(g)

carbondioxide = CO2(g)

water = H2O(g)

The ammonium carbonate was decomposed in the reaction , so ,

(NH4)2CO3(s) → NH3(g) + CO2(g) + H2O(g)

The reactant is on the left side while the product is on the right side. Let us balance the equation to make sure every atom of element is same number on both sides of the equation.

(NH4)2CO3(s) → 2 NH3(g) + CO2(g) + H2O(g)

Final answer:

The decomposition of ammonium carbonate upon heating produces ammonia, carbon dioxide, and water. The balanced equation for this decomposition reaction is: (NH4)(HCO3) → NH3 + CO2 + H2O.

Explanation:

The decomposition of solid ammonium carbonate (NH4)(HCO3) upon heating produces ammonia (NH3), carbon dioxide (CO2), and water (H2O) in gas form. This is a specific type of reaction called a decomposition reaction, which breaks down a compound into its constituent parts. The balanced chemical equation informing this process is: (NH4)(HCO3) → NH3 + CO2 + H2O.

Note from this equation, it is clear that the ammonium carbonate completely disappears as it gets converted into gaseous products upon heating.

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Endothermic reactions are reactions that take in energy. This is usually in the form of heat. An example could be evaporation because heat is being absorbed by water and molecules are moving away from each other.