Calculate the number of atoms in each of the following (iii) 52 g of He.

What will be the mass of one $^{12}C$ atom in g?

Calculate the amount of carbon dioxide that could be produced when (iii) 2 moles of carbon are burnt in 16 g of dioxygen.

Round up the following upto three significant figures: (i) 34.216

In a reaction $A + B_2 \rightarrow AB_2$ Identify the limiting reagent, if any, in the following reaction mixtures. (iv) 5 mol A + 2.5 mol B

If the density of methanol is 0.793 kg $L^{-1}$, what is its volume needed for making 2.5 L of its 0.25 M solution?

How many significant figures are present in the following? (vi) 2.0034

Pressure is determined as force per unit area of the surface. The SI unit of pressure, pascal is as shown below:
$1Pa = 1N m^{-2}$
If mass of air at sea level is 1034 g $cm^{-2}$, calculate the pressure in pascal.

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Use the data given in the following table to calculate the molar mass of naturally occuring argon isotopes:
Isotope Isotopic molar mass Abundance
$^{36}Ar$ 35.96755 g $mol^{-1}$ 0.337%
$^{38}Ar$ 37.96272 g $mol^{-1}$ 0.063%
$^{40}Ar$ 39.9624 g $mol^{-1}$ 99.600%

Calculate the molar mass of the following: (ii) $CO_2$

A welding fuel gas contains carbon and hydrogen only. Burning a small sample of it in oxygen gives 3.38 g carbon dioxide, 0.690 g of water and no other products. A volume of 10.0 L (measured at STP) of this welding gas is found to weigh 11.6 g. Calculate (ii) molar mass of the gas

Fill in the blanks in the following conversions: (ii) 1 mg = ...................... kg = ...................... ng

If 10 volumes of dihydrogen gas reacts with five volumes of dioxygen gas, how many volumes of water vapour would be produced?

the ______ is the length of the path travelled by light in vaccum during a time interval of 1/299792458 of a second 

How many significant figures should be present in the answer of the following calculations? (iii) 0.0125 + 0.7864 + 0.0215

How much copper can be obtained from 100 g of copper sulphate ($CuSO_4$)?

Calculate the density of aluminum if 27.6 cm3 has a mass of 74.6 g.

Express the following in the scientific notation: (ii) 234,000

Which law states that “mass can neither be created nor destroyed”?