Chemical Reactions and Equations — Science STD 10 — Question

A white chemical compound becomes hard on mixing with proper quantity of water. It is also used in surgery to maintain joints in a fixed position. Name the chemical compound.

State Fleming’s left-hand rule.

Is water conservation necessary? Give reasons.

An electric bulb is connected to a 220V power supply line. If the bulb draws a current of 0.5A, calculate the power of the bulb.

Translate the following statements into chemical equations and then balance them.

1. Hydrogen gas combines with nitrogen to form ammonia.
2. Hydrogen sulphide gas burns in air to give water and sulpur dioxide.
3. Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
4. Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

Three elements A, B and C have 3, 4 and 2 electrons respectively in their outermost shell. Give the group number to which they belong in the Modern Periodic Table. Also, give their valencies.

Consider the following elements:
Na, Ca, Al, K, Mg, Li.

1. Which of these elements belong to the same period of the periodic table?
2. Which of these elements belong to the same group of the periodic table?

Explain with a suitable diagram, how a concave mirror converges a parallel beam of light rays. Mark clearly the pole, focus and centre of curvature of concave mirror in this diagram.

Draw a ray diagram to show the formation of a real magnified image by a convex lens. (In your sketch the position of object and image with respect to the principal focus of lens should be shown clearly).

A circular loop carrying a current is placed on a horizontal surface (current is in the clockwise direction). What is the direction of its magnetic field at the centre? What is the direction of the magnetic field at a point outside the surface of the loop?