A catalyst is a substance that_________ the velocity of a chemical reaction.
(A) Increases
(B) Decreases
(C) Changes
(D) None of these
Which of the following is not correct about diffusion?
(A) The rate of diffusion of gases is higher than that of solid and liquid.
(B) Diffusion is possible only when the particles of matter are in constant motion.
(C) The rate of diffusion of gases depends on their volume.
(D) Particles in diffusion move from high concentration to low concentration.
Who proposed the word 'molecule'?
(A) E. Rutherford
(B) J.J. Thomson
(C) Democritus
(D) John Dolton
The melting point of tungsten is____.
(A) 3,083 ° C
(B) 3,830 ° C
(C) 3,380 ° C
(D) 3,308 ° C
Which of the following is not necessary for photosynthesis?
(A) Oxygen
(B) Chlorophyll
(C) Sunlight
(D) Carbon dioxide
The atomic mass of an element has the maximum number of electrons in its second orbit—
(A) 2
(B) 8
(C) 10
(D) 16
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