Write word equations and then balanced equations for the reaction taking place when –

(a) dilute sulphuric acid reacts with zinc granules.
(b) dilute hydrochloric acid reacts with magnesium ribbon.
(c) dilute sulphuric acid reacts with aluminium powder.
(d) dilute hydrochloric acid reacts with iron filings.

When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.

Outline a project which aims to find the dominant coat colour in dogs.

Draw the structure for the following compounds.                

       (i)    Ethanoic acid             (ii)   Bromopentane*
       (iii)  Butanone                   (iv)   Hexanal.

*Are structural isomers possible for bromopentane?

A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?

How is the sex of the child determined in human beings?

(a)  What property do all elements in the same column of the Periodic Table as boron have in common?
(b)  What property do all elements in the same column of the Periodic Table as fluorine have in common?

Calculate the number of electrons constituting one coulomb of charge.

What is an homologous series? Explain with an example.

Why is variation beneficial to the species but not necessarily for the individual?

A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?

What is ozone and how does it affect any ecosystem?

Which of the following terms does not represent electrical power in a circuit?

(a) I²R          (b) IR²          (c) VI          (d) V²/R

Explain the following terms with one example each.

(a) Corrosion
(b) Rancidity

Why do you think that there should be equitable distribution of resources? What forces would be working against an equitable distribution of our resources?

Why does dry HCl gas not change the colour of the dry litmus paper?

How are water and minerals transported in plants?

How would you name the following compounds?

   (i)    CH₃  -- CH₂  -- Br

  (ii)

(iii) 

How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?

Find the power of a concave lens of focal length 2 m.

Why does the cord of an electric heater not glow while the heating element does?