MEDIUM
Earn 100

Which Indian scientist first used the term parmanu?

50% studentsanswered this correctly

Important Questions on Atoms and Molecules

MEDIUM
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination

The reaction of the burning of carbon in oxygen is represented by equation

C(s)+O2(g) → CO2(g)+Heat+Light

When 9.0 g of solid carbon is burnt in 16.0 g of oxygen gas the mass of carbon dioxide gas formed would be:

(Note: Atomic mass of C-12,o u, O=16.0 u)

 

 

MEDIUM
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
Two samples A and B of a pure substance containing elements Y and Z are obtained from two different sources. 5g of sample A contains 1.25g of Z. Sample B is made of 75% of Y by weight. This is an illustration of which of the following laws?
EASY
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
State the law of constant proportions.
EASY
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
For the smallest particle of composition, 'Parmanu' was used by:
MEDIUM
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
In a reaction, 10 g of calcium carbonate reacts with 7.3 g of hydrochloric acid. The products of reaction are 11.1 g of calcium chloride, 1.8 g of water and 4.4 g of carbon dioxide gas. Show that these observations are in agreement with the law of conservation of mass.
EASY
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
State the law of conservation of mass.
MEDIUM
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
Magnesium and oxygen combine in the ratio of 3:2 by mass to form magnesium oxide. How much mass of oxygen is required to react completely with 12 g of magnesium?
MEDIUM
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
State the postulates of Dalton's atomic theory. Is the theory valid at present? Give reasons. 
EASY
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
The indivisibility of atom was proposed by 
EASY
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
State the law of conservation of mass.
EASY
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
Dalton stated that:
EASY
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
State the law of definite proportions.
MEDIUM
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
Law of conservation of mass holds true and can be verified in a school laboratory
MEDIUM
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
Which postulate of Dalton's atomic theory can explain: 
(a) the law of conservation of mass, 
(b) the law of definite proportion?
MEDIUM
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
What was the postulate of Dalton's atomic theory about the divisibility of atom? How was this postulate modified?
EASY
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
Law of conservation of mass was attributed by:
MEDIUM
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
In an experiment, 9.6 g of sulphur bums completely in 9.6 g of oxygen to produce 19.2 g of sulphur dioxide. In another experiment, 9.6 g of sulphur is made to bum completely in 100 g of oxygen. What mass of sulphur dioxide is formed. Which law of chemical combination governs your answer?
MEDIUM
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
Name one Indian and one foreign ancient thinker, who proposed the atomic nature of matter.
EASY
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
Atomic theory was proposed by:
EASY
Science>Chemistry>Atoms and Molecules>Laws of Chemical Combination
Theory of constant composition was proposed by: