Write the balanced equation for the following chemical reactions.
1. Hydrogen + Chlorine → Hydrogen chloride
2. Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride
3. Sodium + Water → Sodium hydroxide + Hydrogen
1. Hydrogen + Chlorine → Hydrogen chloride
H2 + Cl2 → 2HCl
2. Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride
3BaCl2 + Al2(SO4)3 → 3BaSO4 + 2AlCl3
3. Sodium + Water → Sodium hydroxide + Hydrogen
2Na + 2H2O → 2NaOH + H2
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?
Which of the following is not an example of a bio-mass energy source?
(a) wood (b) gobar-gas
(c) nuclear energy (d) coal
Why does an aqueous solution of an acid conduct electricity?
How do Mendel’s experiments show that traits may be dominant or recessive?
What type of oxides are formed when non-metals combine with oxygen?
What are amphoteric oxides? Give two examples of amphoteric oxides.
State Fleming’s left-hand rule.
Why are human beings who look so different from each other in terms of size, colour and looks said to belong to the same species?
An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position and nature of the image.
How many 176 Ω resistors (in parallel) are required to carry 5 A on a 220 V line?
What is ozone and how does it affect any ecosystem?