What is the percentage by mass of H in CH3COOH
1.7%
5.0%
6.7%
7.1%
Correct answer is C
- molecular mass (or molar mass) is 60.05 g/mol
- with 4 atoms of hydrogen present
( 4 / 60 ) X 100
≈6.7%
Stoichiometry is based on the law?
multiple proportion
constant composition
conservation of energy
conservation of mass
Correct answer is D
The principles of stoichiometry are based upon the law of conservation of mass. Matter can neither be created nor destroyed, so the mass of every element present in the product(s) of a chemical reaction must be equal to the mass of each and every element present in the reactant(s).
How many moles of carbon(iv)oxide contains 16.0g of oxygen?
[ C = 12.0, O = 16.0 ]
0.20 mol
0.25 mol
0.40 mol
0.50 mol
Correct answer is D
1 Mole of carbon(iv)oxide contains 32g of Oxygen
: 0.5 Mole of carbon(iv)oxide contains 16g of Oxygen
Which of the following pairs of components have the same molecular mass?
[ H = 1.0, C = 12.0, O = 16.0 ]
Ethene and Ethyne
Ethane and Ethene
Carbon (ii) Oxide and Ethene
Carbon (iv) Oxide and Ethyne
Correct answer is C
Ethene = 28
Ethyne = 26
Carbon(ii)Oxide = 28
Carbon(iv)Oxide = 44