Question

Q If a solution is 400 ml and the solvent is 300ml what will be the percentage of the solute dissolved
a) 100%. b) 45%. c) 25% d) 40%

Q Which of the following are chemical changes?
(i) Decaying of wood (ii) Burning of wood (iii) Sawing of wood (iv) Hammering of a nail into a piece of wood
(a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (i) and (iv)

Q Two substances X and Y on reacting with each other , a third substance, X2Y was formed .according to the following 2 A + B → A2B Which of the following statements concerning this reaction are incorrect? (i) The product A2B shows the properties of substances A and B (ii) The product will always have a fixed composition (iii) The product so formed cannot be classified as a compound (iv) The product so formed is an element (a) (i), (ii) and (iii) (b) (ii), (iii) and (iv) (c) (i), (iii) and (iv) (d) (ii), (iii) and (iv)

Q. Two chemical species A and B combine together to form a product Z which

contains both A and B

A + B → Z

A and B cannot be broken down into simpler substances by simple chemical

reactions. Which of the following concerning the species A, B and Z are correct?

(i) Z is a compound

(ii) A and B are compounds

(iii) A and B are elements

(iv) Z has a fixed composition

(a) (i), (ii) and (iii)

(b) (i), (ii) and (iv)

(c) (ii), (iii) and (iv)

(d) (i), (iii) and (iv)


Q. Ice, water and water vapour look different and display different ………….

properties but they are ………… the same.

a) chemical, physically

b) Physical , Physically

c) chemical, chemically

d) physical, chemically​

Answer 1

Answer:

1. it is c)25%

Explanation:

solution-solvent= solute

400-300=100

percentage= 100/400 = 0.25

0.25*100= 25%