f3 chem(22) - Introducing Chem

Hi everyone. I am STY. I would like to ask you a few questions.

1)
Which of the following statements describes a physical property
of the substance concerned?
A. Aluminium burns in air o give a white powder
B. Common salt is a white powder
C. Iron nails rust in the air.
D. Potassium reacts vigorously when dropped into water
My answer is B. Plz check.

2)
When using sodium nitrite, don't eat or ___.
A. gamble
B. smoke
C. mix it with water
My answer is C, plz check.

3)
When using sulphuric acid, one must wear protective gloves and ___
A. face mask
B. fire extinguisher (absolutely wrong==)
C. respirator
My answer is C, plz check.

4)
Which of the following statements concerning a chemical change
is/are correct?
A. A colour change always occurs.
B. New substances is/are formed.
C. It usually involves a large amount of energy change.
(You may choose more than 1.)
My answer is B and C. Plz check.

5)
If sulphuric acid gets into contact with the eyes one must...
A. apply an eye lotion
B. keep eyes close and wait for medical attention
C. drain with plenty of water.
My answer is C. Plz check.

6)
Classify each of the following processes as
either a physical or chemical change.
a. Growing of a plant. (chemical)
b. Cutting a piece of wood into smaller pieces. (physical)
c. passing electricity through water. (physical)
The answer inside the bracket is my answer. Plz check.


With more explanations, then the best answer you can get.


BY STY~~``