please help with chemistry?

1. Methanol (CH3OH) has a heat of fusion of 3.16 kJ/mol. Which of the following is the heat of solidification that occurs when 63 grams of liquid methanol freezes?

199 kJ

6.32 kJ

6.32 kJ

199 kJ



2. How many moles of liquid water must freeze to remove 100 kJ of heat? (Hf = 334 J/g)

0.30

3.33

16.6

299



3. If 34.1 kJ of heat is released when 5 moles of a gaseous substance condenses, what is the heat of condensation?

171 kJ/mol

6.82 kJ/mol

6.82 kJ/mol

171 kJ/mol



4. In the space station, liquid ammonia is used to transfer heat. If 100 g of liquid ammonia evaporates, then how much heat was removed? (Hv = 5.65 kJ/mol)

17.7 kJ

33.2 kJ

65.0 kJ

565 kJ



5. Consider the amount of heat energy delivered to an object by the same mass of liquid water at 100°C and steam at 100°C. Which of the following is true?

Liquid water delivers more energy because it has more mass.

Steam delivers more energy because it condenses.

Liquid water and steam deliver the same amount of energy.

Steam delivers more energy because it is at a higher temperature.

*** 1 ***
63 g CH3OH x (1 mole / 32.0 g) x (3.16 kJ / mole) = 6.22 kJ

*** 2 ***
100 kJ x (1000 J / 1 kJ) x (1 g / 334 J) x (1 mole / 18.0 g) = 16.6 moles

*** 3 ***
34.1 kJ / 5 moles = 6.82 kJ/mole

*** 4 ***
100 g NH3 x (1 mole / 17.0 g) x (5.65 kJ/mole) = 33.2 kJ

*** 5 ***
steam delivers more energy because it condenses

1. methanol has molecular mass 32 gram/moles. First we find how many moles are in 63 grams. 63/32 = 1.96875 moles
1.96875 x 3.16= 6.22125 KJ

go with the closest answer

2. it takes 334 joules or .334 kilojoules to freeze 1 gram. First to find out how many grams we need to freeze 100/.334
299.4012 grams

water has molar mass of 18

299.4012/18=~16.6334 moles needed

pick the third answer

3. we have 5 moles condensed. So to find amount for 1 mole we divide the amount of heat by 5. 34.1/5= 16.82 KJ/KG

I am too lazy to do 4.

5. steam delivers more energy because it condenses (called latent heat of vaporization)

This is something that you need to learn to do on your own