Is Matter Around Us Pure — Science STD 9 — Question

Which of the following is true?

The boiling point of ethane is, -88°C. This temperature will be equivalent to:

1. 285K
2. 288K
3. 185K
4. 361K

A homogeneous mixture is:

When a crystal of potassium permanganate is placed at the bottom of water in a beaker, the water in the whole beaker turns purple on its own, even without stirring. This is an example of:

1. Distribution.
2. Intrusion.
3. Diffusion.
4. Effusion.

A few substances are arranged in the increasing order ‘forces of attraction’ between their particles. Which one of the following represents a correct arrangement?

The dye from blue fountain pen can be separated by:

There are four elements P, Q, R and S having atomic numbers of 4, 18, 10 and 16 respectively. The element which can exhibit covalency as well as electrovalency will be:

1. P.
2. Q.
3. R.
4. S.

Match the Column I with Column II.

S.No	Column I		Column II
a	9.033 × 1024 atoms	i	46g of He
b	2 moles of Na	ii	15 moles
c	11.2 L of O2, at STP	iii	3.011 × 1023 molecules
d	22g of CO2	iv	16g

The number of electrons in an element X is 15 and the number of neutrons is 16. Which of the following is the correct representation of the element?