Chemical Formulae

Q.

What is the actual molecular mass of chlorine?

Q.

What is the unit of amount of substance?

Q.

What do you mean by significant figures

Q.

Give the Chemical formula for Sulphur dioxide

1. $S{O}_2$

2. $S_4{O}_2$

3. $S_3{O}_2$

4. $S_2{O}_2$

Q.

Define atomic number and mass number. how can you represent an atom by using atomic number and mass number . Give two examples.

Q.

What is the electron configuration of ${\mathrm{Ca}}^{2+}$ ?

Q.

The respective number of significant figures for the numbers $23.023,0.0003$ and $2.1\times {10}^{-3}$ are

1. $5,1,2$

2. $5,1,5$

3. $5,5,2$

4. $4,4,2$

Q. Hydrogen is placed in group - I as it shows similarities in properties with alkali metals (Li, Na, K, etc.). Identify such similar properties between Hydrogen (H) and Alkali metals (M).

1. All of the above.
2. Both form unipositive ion $\left(H^{+}and{M}^{+}ion\right)$.
3. Both can combine with halogens to form halides (HX and MX).
4. Both have a valency of 1 (one).

Q.

What qualitative information is given by the formula ${\mathrm{NH}}_3$.

Q.

What is the number of significant figures in the number 0.00025?

1. 2

2. 5

3. 3

4. 6

Q.

What is the electron configuration for francium?

Q. Write significance of writing chemical formula.

Q.

Is S+O2 = SO2

Is this formula balanced?

Q.

How many p-orbitals are occupied in a $\mathrm{K}$atom?

Q.

What is the ratio by mass of the elements present in the chemical formula of magnesium oxide?

Q. Give the names of the elements and number of atoms of those elements, present in the following compounds.
Ammonium dichromate

Q. An equilibrium mixture for the reaction 2 H2S = 2H2+ S2 has 1 mole of hydrogen sulphide, 0.2 mole of H2 and 0.8 mole of S2 in 2 Litre vessel.The value of Kc is A 0.004 B 0.080 C 0.016 D 0.160

Q.

The term chemical formula mean

Q.

What is the electronic configuration of Chromium in $\left[\mathrm{Cr}\right({\mathrm{NH}}_3{)}_6{]}^{3+}$?

Q.

What would be the electronic configuration of ${\mathrm{Na}}^{+}$, ${\mathrm{Al}}^{3+}$, ${\mathrm{O}}^{2-}$and ${\mathrm{Cl}}^{-}$.

Q. A equilibrium mixture of the reaction, 2H2S=2H2+S2(reversible reaction) had 0.5moleH2S, 0.1 mol H2, 0.4 mole S2in 1 litre vessell.the value of equilibrium constant in.mole/life a)0.004 b)0.008 c)0.016

Q.

An example of an anhydrous salt is-

1. Blue Vitriol

2. Green Vitriol

3. Sal ammoniac

Q. The formula of aluminium oxide is $A{l}_2{O}_3$. If aluminium forms its chloride, what will be the formula of that compound?

1. AlCl
2. ${\mathrm{AlCl}}_2$
3. ${\mathrm{AlCl}}_3$
4. ${\mathrm{Al}}_3\mathrm{Cl}$

Q. Give the names of the elements and number of atoms of those elements, present in the following compounds.
Sodium sulphate

Q. The formula of aluminium oxide is $A{l}_2$$O_3$. If aluminium forms its chloride, what will be the formula of that compound?​

1. AlCl
2. $AlC{l}_2$
3. $AlC{l}_3$
4. $A{l}_{3}Cl$

Q.

Name the following compound

$\mathrm{KCl}$

Q.

Define the term formula?

Q.

What are the combining elements in Hydrogen chloride?

Q.

How many significant figures there are in $3.1205$?

Q.

Show the formation of oxide ion.(Atomic number of oxygen = 8)