Mole concept

How much calcium is present in the amount of $Ca\left(NO_3\right)_2$  that contains 20 g of nitrogen

• 38.0 g Ca

• 48.5 g Ca

• 28.6 g Ca 

• 32.4 g Ca

How much phosphorous is contained in 5 g of the compound $CaCO_3.3Ca_3(PO_4)_2$  ? (Ca = 40.08)

• 0.9 g

• 1.4 g

• 1.9 g

• 2.4 g

Calculate the molecular mass of $(NH_4)_2SO_4.FeSO_4.6H_2O$  

• 362

• 372

• 382

• 392

The number of moles of Ca is 5g of sample $CaCO_3$ is

• 0.125

• 0.25

• 0.05

• 1

Mass of 4 moles of Al atom is

• 108 u

• 108 g

• both A and B

• 108

What will be the volume of 1 gram Helium at NTP?

• 6.5 litre

• 7.5 litre

• 5.6 litre

• 4.6 litre

The number of molecules in 100 ml each of $O_2,NH_3\ and\ CO_2$  at STP are

•  $NH_3>O_2>CO_2$  

•  $NH_3<CO_2<O_2$  

•  $NH_3<O_2<CO_2$  

• The same 

What weight of  $CaCO_3$ (M.W. = 100)  shall be neutralized by 100 ml of 0.1 M HCl?

• 0.25

• 0.5

• 1

• 0.75

It has been found by experiments that if 100 grams of calcium carbonate are decomposed completely the amount of calcium oxide and carbon dioxide formed are

• 56 gms $CaO$ , 44 gms $CO_2$

• 55 gms $CaO$ , 45 gms $CO_2$

• 44 gms $CaO$ , 56 gms $CO_2$

• 45 gms $CaO$ , 55 gms $CO_2$

The correct decreasing order of masses is:

• $3.012\times10^{24}$ molecules of water > 2.5 moles of water > 0.25 gm of water

• 2.5 moles of water > 2.5 gm of water > $3.012\times10^{24}$ molecules of water

• 25 gm of water > 2.5 moles of water > $3.012\times10^{24}$ molecules of water

• None of the above