Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.
Which of the following is physical change?
Burning kerosene
Freezing ice cream
Exposing white phosphorus
Dissolving calcium in water
Correct answer is B
No explanation has been provided for this answer.
22.4 dm3
33.6 dm3
44.8 dm3
67.2 dm3
Correct answer is D
2KClO3 → 2KCl + 3O2
3 moles of oxygen is produced
1 moles of oxygen is 22.4 dm3
3 moles of oxygen is 67.2 dm3
0.44 atmosphere
0.22 atmosphere
0.55 atmosphere
0.33 atmosphere
Correct answer is D
No explanation has been provided for this answer.
146C → X + B
X in the equation above represents
126C
125B
147N
136C
Correct answer is C
146C → X + B
→ X + 0-1e
→ 147X
The postulate of Dalton's atomic theory which still holds is that
atoms can neither be created nor destroyed
the particles of the same element are exactly alike
particles of different elements combine in simple whole number ratio
all elemets are made of small indivisible particles
Correct answer is A
Postulates of Dalton’s atomic theory can used to explain the behavior of matter:
All matter is composed of small tiny particles called atoms. In Greek the word atom is termed as indivisible. The atoms can not be further broken down.
All atoms are indivisible, indestructible, and unchangeable. Atom of an element cannot be created, divided, destroyed, or split into smaller particles or transformed into atoms of other elements or transformed into other atoms in a chemical reaction. They are simply rearrangement of new compound. Dalton’s atomic theory based this hypothesis on the law of conservation of mass and on centuries of experimental evidence.