Empirical Formula

Q.

A gaseous compound of nitrogen and hydrogen contains 12.5 % hydrogen by mass. The molecular formula of the compound if its relative molecular mass is 32, is: [N=14, H=1]

1. ${\mathrm{NH}}_4$

2. ${\mathrm{N}}_2{\mathrm{H}}_3$

3. ${\mathrm{N}}_2{\mathrm{H}}_4$

4. ${\mathrm{N}}_2{\mathrm{H}}_6$

Q.

How would you calculate the empirical formula of acetic acid (${\mathrm{CH}}_3\mathrm{COOH}$)?

Q.

What is the chemical formula of dry ice

Q. Calculate the percentage composition of oxygen in carbon dioxide (co₂)

Q.

Is magnesium hydride ionic?

Q.

Empirical formula of a compound is C₂H₅ and its molecular weight is 58, then its molecular formula is __________.

Q.

In a chemical substance the elements are always present in definite proportions by mass.

1. True

2. False

Q.

What is the Empirical Formula for Sugar?

1. $C_{12}{H}_{22}{O}_{11}$

2. $CHO$

3. $C{H}_2{O}_2$

4. $C_2{H}_{2}O$

Q.

Write the chemical name for the ionic compound ${\mathbf{Mg}}_{\mathbf{3}}{\mathbf{N}}_{\mathbf{2}}$ and mention its molecular weight in brackets after the name.

Q. Question 34
If an element X is placed in group 14, what will be the formula and the nature of bonding of its chloride?

Q.

What is the chemical formula of a compound made of Nitrogen and Oxygen with the mass ratio of 7:8?

1. $N_2{O}_5$

2. $NO$

3. $N_2{O}_3$

4. $N{O}_2$

Q.

Give the empirical formula of :

(a) Benzene (b) Glucose

(c) Acetylene (d) Acetic acid

Q.

Write the chemical name for the ionic compound ${\mathbf{PbCrO}}_{\mathbf{4}}$ and mention its molecular weight in brackets after the name.

Q. An organic compound contains $86.47$% carbon and $6.33$% hydrogen. The empirical formula of the compound is:

1. $C_{16}{H}_{14}O$
2. $C_{14}{H}_{16}O$
3. $C_{10}{H}_{14}O$
4. $C_6{H}_{12}O$

Q.

What is the ionic compound name for ${\mathrm{CaCl}}_2$?

Q. Question 4 (e)
Write the chemical formulae of the following:
(e) Calcium carbonate

Q.

What is the empirical formula of $C_6{H}_{12}{O}_6$?

1. $C_2{H}_6{O}_2$

2. $C{H}_{2}O$

3. $C_2{H}_{2}O$

4. None of the choices

Q.

If a compound is made of sodium, carbon, and oxygen and their % composition are 43.4%, 11.3%, 45.3% respectively. What is the chemical formula of the compound?

1. $NaCO$

2. $N{a}_{3}C{O}_2$

3. $N{a}_{2}C{O}_3$

4. $NaHC{O}_3$

Q.

Determine the empirical formula of a compound containing 47.9% potassium, 5.5% beryllium, and 46.6% fluorine by mass. (Atomic weight of Be=9;F=19; K=39) Work to one decimal place.

Q.

Define empirical formula and molecular formula. How are they related.

Q.

1. $C{H}_{2}O$
2. $CHO$
3. $C{H}_2{O}_2$
4. $C_{2}HO$

Q.

An organic compound contains oxygen, 26.24%, and hydrogen, 4.92%. Find its empirical formula.

Q. What is the difference between formula unit mass and molecular mass and please explain mole concept .

Q. 2, 746g of a compound gave on analysis 1.94g of silver, 0.268g of sulphur and 0.538g of oxygen. Find the empirical formula of the compound.(At. Masses: Ag +108, S =32, O = 16).

Q.

A welding fuel gas contains and hydrogen only. Burning a small sample of it in oxygen gives $3.38g$ carbon dioxide $0.690g$ of water and no other products. A volume of $10.0L$ (measured at STP) of this welding gas is found to weigh $11.6g$. Calculate
(i) empirical formula.
(ii) molar mass of the gas and
(iii) molecular formula

Q. Question 30
A sample of vitamin C is known to contain $2.58\times {10}^{24}$ oxygen atoms. How many moles of oxygen atoms are present in the sample?

Q. A compound contains 43.4% sodium, 11.3% carbon and 45.3% oxygen.
Determine its empirical formula. (Atomic mass of $Na=23C=12,O=16$).

1. $N{a}_{2}C{O}_3$
2. $N{a}_{2}C{O}_4$
3. $NaC{O}_3$
4. $N{a}_{4}C{O}_3$

Q. Give the empirical formula of:

Q.

What is the chemical formula of ammonia?

1. ${\mathrm{NH}}_2$

2. $\mathrm{NH}$

3. ${\mathrm{N}}_2\mathrm{H}$

4. ${\mathrm{NH}}_3$

Q. The empirical formula of acetic acid is:

1. $C{H}_3-COOH$
2. $C_2{H}_{4}O$
3. $C{H}_{2}O$
4. $CHO$