Atomic Weight and Atomic Mass Unit

Q.

The number of molecules in 16.0g of oxygen is

1. 6.02×10²³
2. 6.02×10⁻²³
3. 3.01×10⁻²³
4. 3.01×10²³

Q.

Why is the atomic mass of the sodium atom "23 amu"?

Q.

Equivalent mass of magnesium is 24.

1. True
2. False

Q.

Choose the correct option.

Equivalent mass of zinc is _______________.

1. 32.6

2. 65.3

3. 16.32

4. 21.7

Q. What is the shorthand representation of chemical change?

1. Chemical compounds
2. Chemical equation
3. Chemical formula
4. Chemical symbols

Q.

Define one amu.

Q. The atomic mass of an element expressed in grams is called as .

1. gram atomic mass
2. molecular mass
3. gram molecular mass

Q. _____________________ is the number times one atom of an element is heavier than $1/12$ the mass of an atom of carbon ($C^{12}$).

1. Relative molecular mass
2. Gram atomic mass
3. Gram molecular mass
4. Relative atomic mass

Q.

A gaseous hydrocarbon with a vapour density of 14 contains 85.2% carbon. Calculate its molecular formula.

Q.

What is the molecular weight of a molecule?

Q. Atomic weight of oxygen is _______.

1. 14 a.m.u.
2. 16 a.m.u.
3. 18 a.m.u.
4. 12 a.m.u.

Q.

Which of the following information is conveyed by chemical reaction?

1. The masses of the reactants and products involved in the reaction.

2. The colour changes taking place

3. The structure of the reactants and products

4. The absorption of energy only

Q.

Atomic mass is expressed in:

1. N_A

2. Kg

3. gram

4. a.m.u

Q. Atomic weights are expressed as ___________.

1. grams
2. tons
3. a.m.u.
4. kilogram

Q. Define atomic mass along with some examples. How is it different from molecular mass?

Q.

The atomic mass of Oxygen is 16u.

Considering the above statement, which among the following options can be inferred?

1. The mass is with respect to Carbon -12 atom and the atomic mass of Oxygen is 16 of the mass of carbon 12 atom.

2. The mass is with respect to Carbon -12 atom.

3. The atomic mass of hydrogen is 16 times the mass of Hydrogen.

4. The atomic mass of Oxygen is 16 of the mass of carbon 12 atom.

Q. Find the relative atomic mass of an element made up of six protons and seven neutrons.

1. 12.98 u
2. 13 u
3. 12.38 u
4. 13.98 u

Q.

Which of the following symbols are the correct indication of the phase of a substance in a reaction?

1. (g) -gas

2. all the above

3. (aq)- aqueous

4. (S)-solid

Q. A/An is defined as $\frac{1}{12}$ the mass of an atom of carbon-12.

1. atomic mass
2. isotope
3. molecular mass

Q.

All chemical changes are accompanied by chemical reactions. These reactions are described in sentence form with the help of chemical equations in terms of symbols and formulae of substances involved. Initially, the equation is in a skeletal form which is then balanced so that the total number of reactant species is the same as that of product species.

Can a chemical formula be changed during the balancing of the equation?

Q.

A gaseous compound of nitrogen and hydrogen contains $12.5\%$ hydrogen by mass. Find the molecular formula of the compound if its relative molecular mass is $37$. $\left[\mathrm{N}=14,\mathrm{H}=1\right]$

Q.

What is the reference taken for Relative atomic mass calculation for any element?

1. $\frac{1}{13}$th the mass of one C-12 atom.

2. $\frac{1}{12}$th the mass of one S-32 atom.

3. $\frac{1}{12}$th the mass of one C-12 atom.

4. $\frac{1}{32}$th the mass of one S-32 atom.

Q. A _______ involves both breaking and formation of bonds.

1. Equilibrium
2. chemical reaction
3. none of the above
4. physical reaction

Q. Approximate atomic weight of element is 26.89 . Its equivalent weight is 8.9 . What will be the exact atomic weight

Q. Assertion :Actinium series is so called because it starts with an isotope of actinium. Reason: Actinium is formed in the nature as such and is not formed from the disintegration of any other radioisotope.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. Define atomic mass along with some examples. How is it different from molecular mass?

Q.

Hydrogen and Oxygen combine in the ratio of 1:8 by mass to form water. What mass of oxygen would be required to react completely with 3 g of hydrogen gas?

Q. Gram molecular mass of ammonia is:

1. 22g
2. 17g
3. 18g
4. 20g

Q.

One atomic mass unit is exactly equal to __________ of the mass of one atom of C-12.

1. one-fourteenth
2. one-twelfth
3. one-tenth
4. one-eighth

Q.

A balloon is filled with 15.5 g of water. What will be the number of water molecules contained in the balloon?

1. $4.18\times {10}^{23}$
2. $2.54\times {10}^{23}$
3. $5.18\times {10}^{23}$
4. $3.28\times {10}^{23}$