Topic 1 recap questions
Define the followings;
1. Empirical formula: The simplest mole ratio of atoms in a compound
2. Molecular formula: The actual number of atoms in a compound
3. Mixture: two or more types of atoms joined together not chemically
4. Element: only type of atoms
5. Atom: The smallest stable part of an element (basic unit)
6. Compound: two or more types of atoms joined together chemically
7. Avogadro’s constant: The number of particles in 1 mole of any substance,
6.02x1023
8. Relative atomic mass (Ar): Average mass of an atom of an element compared to
1/12 mass of an atom of carbon-12
9. Relative molecular mass (Mr): Average mass of a compound or molecule
compared to 1/12 mass of an atom of carbon-12
10. Isotopes: Atoms with same number of protons but different number of neutrons
therefore different mass number
`
1. H2 + Cu2O -> 2Cu + H2O
2. C + CO2 -> 2CO
3. Mg + H2SO4 -> H2 + MgSO4
4. Cu + Cl2 -> CuCl2
5. 2Hg+ O2 -> 2HgO
6. Fe + S -> FeS
0.020 x (40.08+32.07+16x4) = 2.723 g ----(x1000)---- 2723 mg
10 / (47.87+35.45x4) x (47.87 + 16x2) = 4.21g
• Q8, 14, 20
Zn
40.6/65.38
/smallest number 0.61/0.6
Ratio
1
Formula
ZnSO4
S
19.8/32.07
0.61/0.6
: 1
O
39.6/16
2.4/0.4
:4