Question

d. can be broken down by passing an electric current through water.
3. There are about 118 different
elements
b. molecules
c. compounds.
d. mixtures
4. If you heat a liquid, it will ultimately change into
a a solid
b. a gas
a air
e either a solid or a gas depending on temperature.
d. neither solid nor gas-it will always remain a liquid.
5. When two elements are brought together, they
a. always form a mixture.
b. always form a compound.
e may form a mixture or a compound depending on the conditions.
d. may form a mixture or a compound depending on what they like.
6. Which of the following is not a mixture?
b. sea water
Je pure water
d. soil
7. The valency of which of these elements is zero?
a. iron
b. helium
c. hydrogen
8. Which of these is the formula for calcium hydroxide?
4. CaOH
b. CaOH
c. Ca(OH)
d. Ca(OH),
9. The equation Na + H,O- NaOH + H, is
a correct.
b. incorrect since it is not balanced.
c. incorrect since sodium does not react with water.
d. incorrect since hydrogen should be written as H and not H,
d. oxygen
B. VERY SHORT-ANSWER QUESTIONS: Give one-word answers.
1. What is the smallest particle of an element that can take part in a chemical reaction? Atom
2. The smallest particle of a compound is molecule
3. Name an element which exists in the free state in nature. Neon
4. Name an element whose atoms occur in pairs. Oxygen
5. If the formula of an element is X,, its atomicity is
6. If two compounds that do not react chemically are mixed, what do we get?
7. From which of these two can elements be more easily separated-a mixture or a compound?
B. Does a symbol represent an atom or a molecule? What are the symbols for each of the following?
a. cobalt
b. copper
c. chlorine
d. carbon
Wri the formulae for
a. sulphuric acid
b. calcium hydroxide
d. common salt.
If a certain compound has a formula H,X, what is the valency of X?
c. sugar
STRUCTURE OF MATTER • 35​

Answer 1

Answer:

This much long I can't read bro give one by one

Answer 2

Answer

3 b

4 b

5 c

these are the ans