Here are the answers to the questions:
Q2. a) i) Provide the SI units for the following quantities:
- Power: Watt (W)
- Amount of substance: Mole (mol)
- Electric current: Ampere (A)
- Thermodynamic temperature: Kelvin (K)
- Time: Second (s)
Q2. a) ii) Distinguish between density and relative density of a substance.
- Density is the mass per unit volume of a substance, typically measured in kg/m3 or g/cm3. It is an absolute measure of how much matter is packed into a given space.
- Relative density (or specific gravity) is the ratio of the density of a substance to the density of a reference substance (usually water at 4∘C for liquids and solids, or air for gases). It is a dimensionless quantity, meaning it has no units.
Q2. a) iii) A salt solution is made by dissolving 50g of salt in 250cm³ of water. Calculate the density of the salt in kg/m³.
Assumption: The question asks for the mass concentration of the salt within the volume of water, expressed in density units.
Step 1: Identify the given values.
Mass of salt (m) = 50g
Volume of water (V) = 250cm3
Step 2: Calculate the mass concentration in g/cm3.
Concentration=Vm
Concentration=250cm350g
Concentration=0.2g/cm3
Step 3: Convert the concentration from g/cm3 to kg/m3.
We know that 1kg=1000g and 1m=100cm, so 1m3=(100cm)3=1,000,000cm3.
0.2cm3g×1000g1kg×1m31,000,000cm3
0.2×10001×1,000,000m3kg
0.2×1000m3kg
Concentration=200m3kg
The density of the salt (mass concentration) is 200kg/m3.
Q2. a) iv) Give three (3) examples of vector quantities.
- Displacement
- Velocity
- Force
Q2. b) i) What are isotopes?
Isotopes are atoms of the same element that have the same number of protons (atomic number) but different numbers of neutrons, resulting in different mass numbers. They exhibit similar chemical properties but may have different physical properties.
Q2. b) ii) Name the three (3) main particles of an atom with their respective charges.
- Proton: Positive charge (+1)
- Neutron: No charge (neutral, 0)
- Electron: Negative charge (−1)
Q2. b) iii) Name the type of bond present in each of the following:
The substances for this question are not visible in the provided image. Therefore, this question cannot be answered.