Significance of a Molecular Formula

Q.

What does a chemical formula represent?

1. Number of atoms of each element present in one molecule of the compound.

2. Represents bonding between atoms.

3. Represents the number of electrons shared.

4. It represents a mole of an atom.

Q. 8. In acrystalline solid , X atoms occupy HCP and 1/4 of tetrahedral voids are occupied byY atoms . then the empirical formula of the crystallie solid is - 1. X2Y 2. XY2 3.X4Y 4. XY

Q.

Write the molecular formulae for the oxides and sulphides of following elements present.

(a) Sodium (b) Calcium

(c) hydrogen

Q.

Write the molecular formulate for the following compo unds and name of the elements present.

(a) Baking soda (b) Common salt

(c) Sulphuric acid (d) Nitric acid

Q. The empirical formula of C₂H₂ and C₆H₆ is:

1. C₃H₃
2. C₂H₂
3. CH
4. C₆H₆

Q.

Calculate molecular formula of a compound is ${\mathrm{C}}_6{\mathrm{H}}_{18}{\mathrm{O}}_{3.}$ Find its empirical formula.

Q. Translate the following statement into a chemical equation and then balance it:

Hydrogen sulphide gas burns in the air to give water and sulphur dioxide. [3 Marks]

Q. How NaAlO2 formula formed

Q.

Give the relationship between molecular formulae and empirical formulae.

Q.

How will you determine the empirical formulae?

Q. Burning of wood is a physical change.

1. False
2. True

Q. Burning of paper is a physical change.

1. False
2. True

Q.

In which of the following cases, is the empirical formula same as the molecular formula?

1. C₁₂H₂₂O₁₁

2. C₆H₆

3. C₃H₅COOH

4. C₆H₁₂O₆

Q. Number of formula unit in unit cell of MgO, ZnS, Pt in( fcc)

Q.

What is the chemical formula of methanal?

Q. Does eq wt of some compounds depend on formula

Q.

Write the chemical formula of simplest ketone.

Q.

Which of the following changes indicate that a chemical change has not been taken place?

1. No new substance is formed
2. Absorption or release of heat
3. Change in colour
4. Evolution of gas

Q.

The formula for quick lime is ___ $\left[\mathrm{CaO},\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\right]$.

Q. Burning of paper is a physical change.

1. True
2. False

Q.

What is the empirical formula of Glucose?

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

2. $C{H}_3{O}_2$

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

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

Q. No. Of structures possible for a compound with molecular formulaC5H10 i.8 ii.10 iii.6 iv. 4