3-Quantitative Chemistry Flashcards
1
Q
What is relative formula mass (Mr)
A
The relative atomic masses of all the atoms in the molecular formula added together
2
Q
How do u calculate percentage mass of an element in a compound
A
Percentage mass of an element in a compound = Ar x number of atoms of that element /Mr of the compound. X100
3
Q
What is one mole of any substance
A
The amount of that substance that contains the Avagrado number of particles- 6.02x10*23
4
Q
What is the equation for the number of moles
A
Number of moles= mass(g) / Mr
5
Q
What are the reasons for a change in mass in an unsealed reaction
A
If a gas is a product or reactant
6
Q
What does the big number in front of chemical formulas in equations represent
A
How many moles of that substance there are
