Science Class 8th

381. _______ is formed during the reaction of Sulphuric Acid and Zinc Metal.

A) Nitrogen

B) Oxygen

C) Hydrogen

D) Carbon Dioxide

382. During the chemical reactions atom of the reactants rearrange to give new compounds or products;

A) True

B) False

383. We write the chemicals in a simple way by using:

A) Numbers

B) Symbols

C) Elements

D) None of the above

384. Simple way of writing a compound is called symbol:

A) True

B) False

385. Short way of writing a chemical change is called:

A) Symbol

B) Expression

C) Regression

D) Equation

386. Reactants are written on the _____ side of the equation

A) Right

B) Left

C) Can be written on both sides

D) None of the above

387. Products of the chemical reaction are written on the _____ side of the equation,

A) Right

B) Left

C) Both A and B

D) None of the above

388. Al(s) + O2 (g) -> Al2 O3 (s)

A) Sublimation

B) Solid

C) Saturate

D) Separate

389. Which of the following is used In Window Pans:

A) Sodium

B) Aluminum

C) Nitrogen

D) Iron

390. ______ is used in Match Industry.

A) Nitrogen

B) Sodium

C) Sulpher

D) None of the above

391. ______ is used in inflating balloons.

A) Nitrogen

B) Chlorine

C) Oxygen

D) Hydrogen

392. Which of the following can be learnt from an equation:

A) The Elements or compounds taking place in the chemical reaction

B) The New elements or compounds formed

C) The state of reactants and products.

D) All of the above

393. If the number of atoms of elements is not equal on both sides of the chemical equation then they should be made equal by inserting co efficient with the reactants or products where required.

A) True

B) False

394. Inspecting an equation properly and putting appropriate co-efficient before the reactants or products so both sides can be equal.

A) Balancing Principle.

B) Inspection Method

C) Error Method.

D) Both B and C

395. Lavoisier was a _____ scientist.

A) English

B) German

C) Polish

D) French

396. ______ proved that total mass of the reactant equals to the mass of the products during the chemical reaction.

A) Newton

B) Avagrodo

C) Lavoisier

D) Pascal

397. Total mass of the reactant equals to the mass of the products during the chemical reaction.

A) True

B) False

398. Matter cannot be created but can be destroyed.

A) True

B) False

399. Which of the following is known as synthesis or combination reaction?

A) Addition Reaction

B) Decomposition reaction

C) Elimination Reaction

D) Non of the above

400. Some compounds on heating decompose into simpler compounds or elements.

A) True

B) False