Chapter 3- Amount of substances Flashcards
Define ‘Mole’
6.02x10^23 particles
Why is a mole 6.02x10^23 particles?
12g of carbon 12 contains 6.02x10^23 atoms.
What does one mole of Uranium atoms weigh?
238.1g
What is the equation for working out number of moles?
number of moles= mass (g)/ Mr
Calculate the number of moles present in 4.6g of Germanium.
0.0633608815g
Calculate the mass of 8.4moles of
copper arsenide, Cu3As in kilograms.
3.935232Kg
What is the empirical formulae?
The simplest whole number ratio of atoms of each element in a compound
Calculate the empirical formulae of C4H10
C2H5
In an experiment , 1.303g of Calcium Combines with 2.23g of chlorine to form a compound. Calculate the empirical formula.
CaCl2
What does it mean when a salt is hydrated?
Water is part of their crystalline structure
What 2 assumptions must you make when using experimental data to calculate the amount of water in a hydrated salt?
All the water has been lost
There is no further decomposition
What is the formula to calculate concentration from the number of moles?
Volume (dm3)/ number of moles
What value is the molar gas volume at RTP?
24sm3mol-1
How do you calculate number of moles of a gas?
Volume (dm3)/ 24
State the ideal gas equation.
p(Pa)V(m3)=nR(8.314Jmol-1)T(K)
Calculate the pressure of 105cm3 of 0.2moles of gas at 260K.
4117409.52KPa
Convert 50C into K.
313K
What is the stoichiometry of an equation?
The ratio of the amount, in moles, of each substance
What is the formula to calculate % yield?
(actual yield/theoretical yield)*100
1.15g of Sodium reacts with excess chlorine, forming 1.872g of Sodium Chloride. What is the % yield for this reaction?
64%
What is the formula for atom economy?
(Mr of desired products/Mr of all products*100
How could you increase the atom economy for a reaction
find a use for the unwanted products
