Percentage + Conservation by Mass Flashcards
1
Q
Percentage by mass formula
A
Ar x number of those atoms in a compound / Mr of a compound
2
Q
Calculate the percentage by mass of oxygen in CO2
A
Ar of O is 16
16 x 2 oxygen atom in the compound = 32
Mr of CO2 = 44
32 + 12
32/44= 0.72727..
0.72727 x 100 = 72.7%
3
Q
What is the law of conservation of mass?
A
Matter cannot be created or destroyed, only transferred from one form to another
4
Q
If the law of conservation of mass is true, what happens to the mass that is gone after a chemical reaction
A
It is probably gas that is released into the air, but it has not been destroyed or lost
5
Q
Calcium oxide + hydrochloric acid ->
A
calcium chloride + water
