Correct Answer: A. NH₃= 17

Correct Answer: B. pressure

Correct Answer: C. 394.5 g

Explanation

To calculate the mass of a substance, we can use the formula: Mass = Volume x Density Given the volume of ethanol is 500 mL and the density of ethanol is 0.789 g/mL, we can plug the values into the formula: Mass = 500 mL x 0.789 g/mL = 394.5 g

Correct Answer: B. Cyclohexane

Correct Answer: A. Sp³

Correct Answer: D. \(400cm^3\)

Explanation

Molarity = 0.100 mol / 0.250 mol dm3

= 0.100 mol / 0.250 dm3 * 1000 cm3/dm3

= 400 cm3

Volume (V) = Amount (n) / Concentration (C)

Given that the amount of HCl is 0.100 mol and the concentration of the solution is 0.250 mol/dm³, you can calculate the volume:

Volume (V) = 0.100 mol / 0.250 mol/dm³ = 0.4 dm³

Since 1 dm³ is equal to 1000 cm³, you can convert the volume from dm³ to cm³:

Volume (V) = 0.4 dm³ × 1000 cm³/dm³ = 400 cm³

Therefore, the volume of 0.100 mol of HCl in a 0.250 mol/dm³ solution is 400 cm³.

Correct Answer: C. The rate of reaction is proportional to the number of effective collisions

Explanation

The rate of reaction is proportional to the number of effective collisions. This means that if the number of collisions increases, the rate of reaction will also increase. These successful collisions are known as effective collisions. The rate of reaction is directly proportional to the number of effective collisions between reactant molecules. In other words, the more frequent and successful the collisions, the faster the rate of the reaction.

Correct Answer: D. Milk of magnesia 10.5

Explanation

(a)(i) The common name given to group VII elements is Halogens.

(ii) Hydrides of the first two elements in group VII: (1) Hydrogen fluoride (2) Hydrogen chloride.

(iii) Three chemical properties of group VII elements are: (1) High electron affinity/strong oxidation 4-gents/electron acceptor. (2) High electronegative (3) React with hydrogen to form acid. (4) Form salts with metals. (5) React with alkalis to form salts. (6) React with water to form acids. (7) Displacement of lower halogens from their acids/salts. (8) Reacts with hydrocarbons to form alkyl halids.

(b) Copy and complete the following table:

(c)(i) Define the following processes: I. Nuclear fission – splitting of a heavy nucleus into smaller nuclei (of smaller mass) with release of (large amount of) energy and radiations. II. Nuclear fusion –combination of smaller nuclei to form a large nucleus with the release of (large amount of) energy and radiation.

(ii) Give one use of each process in (c)(I). I. Used to generate electricity/nuclear or hydrogen bomb/ production of new elements/production of radioisotopes. II. Used to produce nuclear weapon/ atomic or hydrogen bomb/production of new elements/production of radioisotopes.

(c)(i) List three types of radiation that are produced during radioactivity: (1) alpha (2) beta (3) gamma.

(d)(ii) Arrange the radiation listed in (d)(i) in order of increasing:

I. Penetrating power — \(\alpha\), < \(\beta\) < \(\gamma\)

II. Ionizing power — \(\gamma\) < \(\beta\) < \(\alpha\)

Correct Answer: A. The activation energy