On complete combustion, 44 g of a sample of a compound gives 88 g CO2 and 36 g of H2O. The molecular formula of the compound may be:
1.
2.
3.
4.
The maximum number of molecules is present in which of the following?
1. 15 L of gas at STP
2. 5 L of gas at STP
3. 0.5 g of gas
4. 10 g of gas
The number of moles present in 2.5 litres of 0.2 M are:
1. 0.25
2. 0.5
3. 0.75
4. 0.2
Which of the following statements is correct?
1. 1 mole of electrons weights 5.4 mg .
2. 1 mole of electrons weights 5.4 kg.
3. 1 mole of electrons weights 0.54 mg.
4. 1 mole of electrons has 1.6 C of charge.
1cc N2O at STP contains:
1. | \({1.32 \over 224} \times10^{23}~\text{electrons}\) | 2. | \({6.02 \over 22400} \times10^{23}~\text{molecules}\) |
3. | \({1.8 \over 224} \times10^{22}~\text{atoms}\) | 4. | All of the above |
The number of valence electrons present in 0.53 grams of Na2CO3 is:
1.
2.
3.
4.
At STP, the density of CCl4 vapour in g/L will be closest to:
1. 8.67
2. 6.87
3. 3.67
4. 4.26
The weight of 1x1023 molecules of CuSO4.5H2O is:
1. 34.42 g
2. 41.42 g
3. 54.44 g
4. 68.94 g
lf NA is Avogadro's number, then the number of valence electrons in 4.2 g of nitride ions (N) will be:
1. | 3.2 NA | 2. | 1.6 NA |
3. | 2.4 NA | 4. | 1.2 NA |
ln the final answer of the expression \(\large{\frac{(29.2-20.2)\times(1.79\times10^5)}{1.37}}\)
the number of significant figures after solving the expression is:
1. | 2 | 2. | 4 |
3. | 6 | 4. | 7 |