The element has a mass number of 40 and an atomic number of 20. Consider the statements and decide which of them are correct. 1 The nucleus has a relative…

Find the positive solution of the following simultaneous equations: Answer: 14) x = 3 ; y = 1 2x – y = 5y = 2x – 5 Substitute this expression…

At 200 °C, potassium hydrogencarbonate decomposes according to the following equation. What is the loss in mass when 50.0 g of potassium hydrogencarbonate are heated at 200 °C to constant…

In statistics Spearman’s rank correlation coefficient is given by the formula: Rearrange the formula to make ∑ 2 d the subject: Rearrange the formula to make ∑ 2 d the…

A force F is applied to the piston X of a brake pedal. This force is transmitted, hydraulically, to piston Y as shown in the diagram. Diameter of piston X…

A gene controls the production of chlorophyll in lettuce plants. The recessive allele of this gene blocks chlorophyll formation which prevents seedling development. Plants heterozygous for this gene were cross…

Which changes to the conditions will increase the yield of the salt in the exothermic reaction shown? Answer: 9) B Firstly, catalysts do not affect the equilibrium position and so,…

A health club monitors the average heart rate of its members when using a cardiovascular workout machine. The lower quartile of the heart rate is 115, the upper quartile is…