Miss Beagley Extra Bits

Question 1

Formula of Hydrated salts

Answer 1

Weight the empty crucible
Add the hydrated salt + weigh it again
Heat the crucible gently for 1 min and strongly for 3 mins
Leave it to cool and weigh the anhydrous

Question 2

What is water of crystallisation

Answer 2

Water molecules having a crystalline structure

Question 3

Example of hydrated salts

Answer 3

Blue crystals of hydrated copper II sulfate is heated
Breaking the bonds of water molecules
Leaving a white anhydrous copper II sulfate

Question 4

What makes it anhydrous

Answer 4

The crystalline structure is lost however it’s very difficult to remove every trace of water in the compound

Question 5

What are the assumptions

Answer 5

1. If the anhydrous and hydrated form have similar colours, it’s difficult to distinguish if all of the water has been removed
   - constantly heating to a constant mass
2. Salts can decompose when heated like strong copper II heated that form black copper II oxide so it’s harder to see if there no color change

Question 6

Formula for moles and volumes

Answer 6

Moles = concentration * volume

if you’re measuring in cm cubed, divide by 1000

Question 7

What is a standard solution

Answer 7

A solution of the known concentration

Question 8

how do you prepare a standard solution?

Answer 8

dissolve the exact mass of solute in the solvent

use moles to work out the mass required to prepare a standard solution

Question 9

molar volume

Answer 9

molar gas volume = volume per mole of gas at standard temperature and pressure

Question 10

the formula for the ideal gas equation

Answer 10

pV=nRT
P - pressure (KaP - P = 10^3)
V - volume (Cm^3 - M^3 = 10^-6) OR (Dm^3 - M^3 = 10^-3)
n - moles
R - ideal gas constant (8.31 mol^-1 K^-1)
T - temperature (Degrees to Kelvin = ? + 273)

Question 11

what is the ideal gas equation?

Answer 11

This provides a solution to show that an average with pressure and temperature approximations because different experiments need different conditions to give off a more accurate measurement

Question 12

What assumptions make up the ideal gas

Answer 12

random motion
elastic collision
negligible size
no intermolecular forces

Question 13

why is it wrong to assume room temperature is 25 degrees

Answer 13

it’s a standard temperature in chemistry so using the ideal gas equation tells us molar gas volume (24.5dm^-3 mol^-3) at 25 degrees and 101KaP

Question 14

what is stoichiometry

Answer 14

the ratio in a balanced equation, balanced numbers that give ana amount in moles for each substance