Amount Of Substance Flashcards
What is molar mass and what is it’s units?
The mass of one mole of something
G mol ^-1
What is the value of a mole and what is this value called?
6x10^23
Avogadro’s constant
Calculate the molar mass of Ni(OH)2
Mr = 58.7 + (2x(16+1)) = 92.7
92.7 g mol^-1
How do you calculate moles, when conc is not given?
Moles = mass of a substance / molar mass
Calculate the moles of CaBr2 in 39.98g
0.2 moles
A compound has 0.05 moles and weighs 2.6 g. Find it’s relative molecular mass
52
What is the equation of moles when concentration is given?
Moles = conc x volume / 1000
When in cm^3
A 0.5 mol dm^-3 solution of ZnSO4 contains 0.08 moles what volume does this occupy?
0.16 dm^3
What mass of sodium hydroxide needs to be dissolved in 50cm3 of water to make a 2M solution?
4g
What is the equation to work out the mass of a gas (in standard conditions) when only volume is given?
Moles = volume / 24 (in dm^3) Moles = volume / 24000 (in cm^3)
What volume in cm^3 does 0.02 moles of hydrogen gas occupy in standard conditions?
= 0.02 x 24000 = 480 cm ^3
What is the ideal gas equation?
PV = nRT
At a temperature of 60oC and a pressure of 250KPa a gas occupied a volume of 1100 cm3 and had a mass of 1.6g.
Find it’s relative molecular mass
16
Balance the equation
C2H6 + O2 —> CO2 + H2O
C2H6 + 3.5O2 —-> 2CO2 + 3H2O
Calculate the mass of iron oxide produced if 28g of iron is burnt in air in this equation:
2Fe + 1.5 O2 —-> Fe2O3
40g of iron oxide