How many carbon atoms are there in 12.0 g of carbon-12?
12
6.022 × 1023
12.044 × 1023
How many atoms are there in a molecule of ammonia, NH3?
2
4
How many atoms are there in 0.2 mol of methane molecules, CH4?
1.204 × 1023
3.011 × 1024
What is the mass of one silicon atom (relative atomic mass = 28.1)?
1.692 × 10-21 g
2.143 × 1022 g
4.666 × 10-23 g
What is the molar mass of glucose, C6H12O6 (relative formula mass = 180.0)?
180.0 g/mol
30.0 g/mol
7.5 g/mol
What is the amount, in mol, of oxygen atoms in 8.0 g of oxygen atoms (relative atomic mass = 16.0)?
2.0 mol
24.0 mol
0.5 mol
What is the mass of 0.75 mol of hydrogen molecules (relative formula mass = 2.0)?
1.5 g
2.67 g
0.375 g
Magnesium reacts with dilute hydrochloric acid. When the reaction is complete, some magnesium is still visible. What does this mean?
Magnesium is the limiting reactant
Hydrochloric acid is the limiting reactant
The reaction is not finished
Hydrogen reacts with oxygen to produce water: 2H2 + O2 → 2H2O. What is the maximum mass of oxygen that will react with 6.0 g of hydrogen? (Relative formula masses: H2 = 2.0, O2 = 32.0)
48.0 g
64.0 g
96.0 g
In a reaction, 1.0 mol of copper reacts with 0.25 mol of oxygen to form 0.50 mol of copper oxide. What is a correct balanced equation for this reaction?
4Cu + O2 → 2Cu2O
4Cu + 2O2 → 4CuO
Cu + O2 → CuO2