Matter in Our Surroundings — Science STD 9 — Question

Which of the following can be separated by using a separating funnel and which cannot be separated by using a separating funnel?

1. Water and kerosene mixture.
2. Water and acetone mixture.

Give reasons for your answer.

Name two solid, two liquids and two gaseous elements at the room temperature.

The mass number of an element is 23 and it contains 11 electrons. What is the number of protons and neutrons in it? What is the atomic number of the element?

Atom A has a mass number 209 and atomic number 82.
Atom B has a mass number 209 and atomic number 83.

1. How many protons atom A has?
2. How many protons atom B has?
3. Are atoms A and B isotopes of the same element?

What is Brownian motion? Draw a diagram to show the movement of a particle (like a pollen grain) during Brownian motion.

Classify the following materials as homogeneous mixtures and heterogeneous mixtures:
Soda-water, Wood, Air, Soil, Vinegar, Alcohol and water mixture, Petrol and water mixture, Chalk and water mixture, Sugar and water mixture, Copper sulphate solution.

Explain the following:
When an incense stick is lighted in the corner of room, its fragrance spreads quickly in the entire room.

Which law states, that in a chemical compound, elements always combine in a fixed proportion?

Explain the formation of (i) sodium ion, and (ii) chloride ion, form their respective atoms giving the number of protons and number of electrons in each one of them. What is the reason for positive charge on a sodium ion and a negative charge on a chloride ion?

Define a compound. Give two points of evidence to show that sodium chloride is a compound.