Answer: Protons
WHY?
Changing electrons will only result in the same element having different charges and hence, changing it's chemical properties.
Changing neutrons will not change an element but it will result in an isotope forming instead. (Isotopes are elements of the same type with different neutron numbers.)
However, changing the proton number would immediately change the nucleus composition, resulting in a change in element with a negative charge as there are more electrons than protons. This results in a expansion in valance electrons's distance from the nucleus. This results in a change in chemical properties of the element.
Therefore, a change in Protons is the answer.
Answer:
- <u>25.0 liter of nitrogen gas</u>
Explanation:
<u>1. Chemical equation</u>
Ammonium nitrite is a solid compound that decomposes into nitrogen gas and water vapor as per this chemical equation:

<u>2. Mole ratio</u>

<u>3. Volume ratio</u>
Since, both species are gases and are at same temperature and pressure, the volume ratio is equal to the mol ratio.
Thus, the volume ratio is:

<u>4. Use the volume ratio with the known amount of water produced</u>

Answer:
= 25.05°C
Explanation:
Given:
the value of ΔHcomb (heat of combustion) for dimethylphthalate (C10H10O4) is = 4685 kJ/mol.
mass = 0.905g of dimethylphthalate
molar mass = 194.18g dimethylphthalate
number of moles of dimethylphthalate = ???
= 21.5°C
= 6.15 kJ/°C
= ???
since we have our molar mass and mass of dimethylphthalate ;we can determine the number of moles as;
0.905g of dimethylphthalate × 
number of moles of dimethylphthalate = 0.000466 moles
Heat released = moles of dimethylphthalate × heat of combustion
= 0.000466 moles × 4685 kJ
= 21.84 kJ
∴ Heat absorbed by the calorimeter =

21.84 kJ =6.15 kJ/°C 
21.84 KJ = 
21.84 KJ =
- 132.225 kJ
21.84 KJ + 132.225 kJ = 
154.065 kJ = 
= 
=25.05°C
Answer:
The new volume of gas would be 30 L.
Explanation:
This is an example of a Combined Gas Laws problem.