Some Basic Conc...

Which  of the following weights the  most?

$$AB_2$$ and $$A_2B_2$$ are two compounds of the elements A and B. 0.25 mole of each of these compounds weights 9 g and 16 g respectively. Find the atomic masses of A and B. 

Hemoglobin contains 0.334 % of iron by weight. The molecular weight of hemoglobin is approximately 67200.The number of iron atoms (Atomic weight of Fe is 56) present in one molecule of hemoglobin is 

The critical density of the gas $$CO_2$$ is 0.44 $$g\ cm^{–3}$$ at a certain temperature. If $$r$$ is the radius of the molecule, $$r^3$$ in $$cm^3$$ is approximate: 

The solubility of potassium chloride in water at $$20^oC$$ is $$34.7g$$ in $$100g$$ of water. The density of solution is $$1.3g/ml$$. Calculate the % of mass/volume concentration of potassium chloride.

In $$\overset { 14 }{ \underset { 7 }{ N }  } $$ if mass attributed to electron were doubled & the mass attributed to protons were halved, the atomic mass would become approximately:-

The weight of 1 mole of a gas of density is $${\text{0}}{\text{.1784}}{\kern 1pt} {\kern 1pt} {\text{g}}{\kern 1pt} {{\text{L}}^{ - 1}}{\text{at}}{\kern 1pt} {\text{NTP}}{\kern 1pt} {\text{is}}{\kern 1pt}  - $$

Find the concentration of glucose in blood which have osmotic pressure $$\pi = 7.7 \ atm$$ at $$T = 25^oC$$

$$12$$ gm of an alkaline earth metal gives $$14.8$$g of its nitride. The atomic mass of metal is:

A gas mixture contains $$50\%$$ helium and $$50\%$$ methane by volume. What is the percent by weight of methane in the mixture?