I believe it means that it takes a lot of heat in joules to make silicon vaporize so it stays solid until a great deal of heat has been added. By comparison, water has a latent heat of about 2260 joules per gram so vaporizes much more readily than silicon.
The size of the object and the distance between the objects.
First step in answering the question is to establish a balanced chemical reaction equation. More specifically, a combustion chemical equation.
CH4 + 2O2 ---> CO2 + 2H20
Then using dimension analysis:
Answer:

Explanation:
We are given the percent composition: 22.5% phosphorus and 77.5% chlorine.
We can assume there are 100 grams of this compound. We choose 100 because we can simply use the percentages as the masses.
Next, convert these masses to moles, using the molar masses found on the Periodic Table.
- P: 30.974 g/mol
- Cl: 35.45 g/mol
Use the molar masses as ratios and multiply by the number of grams. 

Divide both of the moles by the smallest number of moles to find the mole ratio.


The mole ratio is about 1 P: 3 Cl, so the empirical formula is written as:<u> PCl₃</u>
Answer: physical
Explanation: water doesn't undergo chemical change when it melts and freezes, because either way frozen or not the molecules are the same. hope i helped ;] BRAINLYEST?????