avogadro law confusion

1)MM of ccl₄=12+142=154
no of moles of atoms =10²⁵/N_A
no of moles of molecules=1/5*10²⁵/N_A
mass of ccl4=no of moles of ccl4 * MM
volume of ccl4=mass/density=1/5*10²⁵/N_A
* MM1.5gm cm-3

@qwerty yes u are correct :D

2)its easy....here the gas is in NTP.we know that the mass of 22.4 L of any gas at NTP is equal to its molar mass.
so mloar mass is=22.4*1.5=33.6gm.

@qwerty,unless otherwise stated i think it is generally assumed that the gases are in NTP

Ans 3) density = 0.999841 at 273 K

density = mass/volume

put the values, mass = 18g

answer is 18.00286246ml.

The volume occupied by one mole of substance is called the molar volume. The molar volume of liquid water is 18.016/density. At 277 K, the molar volume is 18.016 mL. For liquid water, the molar volumes of liquid water increase to 18.03 mL at both 269 K and 285 K.

2 , 3 and 4 ? cmon give it a try

yes and that gives the answer as 0.426 L

Try these questions it is similar to the kind of questions where we feel that the question is incomplete but actually it is not ::

1) What volume of carbon tetra cholride CCl₄ having density 1.5gm cm^-3 contains 10 ²⁵ atoms ?

2) What is the molar mass of a gas if 1.00 L of the gas weighs 1.50 gm at 273 K and one atmospheric pressure ?

3) What is the molar volume of water at 273 K ? Density of water is 1gmcm^-3.

4) What is the volume of water vapour in a container , where the side of cubical container is 22.4 dm and the mass of water vapour is 18 gm and the conditions are STP.

sharad u are correct (i did not want to change the question because nowhere it was mentioned that the conditions are same)....it is given that the mass is same for both the gases (and they are not at STP) obviously i did not know this earlier that unless it is mentioned we cannot use the STP CONDITION

yeh same no of atoms too.( sorry woh post galti se delete ho gaya, I was just going to click on edit aur delete par kar diya)

any ways thanks.

hey khyati,the no of atoms will b same..

@ prateek ,avogadros law states "equal volumes of gases contain equal number of molecules ".

here,the mass of both gases is the same,but not the volume.so they will contain unequal no of molecules.

no of moles of oxygen gas will be =10/32 and ozone will be=10/48.
no. of atoms of oxygen gas will be=10/32*2*N_A and in ozone it will be=10/48*3*N_A

so both contain equal no of atoms.......

@ prateek how can we assumethe conditions of pressure and temperatue ?? these functions depend on the gas itself . If both ozone and oxygen were in identical jars , den they will hav equal no of molecules or moles only if they would hav exerted same pressure at same temperature....the converse is also true

if they would hav exerted same pressure at same temp in 2 identical jars, then only they would hav equal no of moles

Do we measure the gases in terms of weight or volume?
Cuz in the question when you say 10gm of Oxygen or 20gm of Ozone, what does that mean? Is it appropriate to calculate in terms of weight?
If so, then our answer is easy:-

n= weight of sub./ gm.mol. wt.

That means simply calculate the no.of moles and then from the formula of N=6.023*(10^23)*n calculate the no.of molecules.
where N is the no.of molecules and n is the no.of moles.