Question Text
Question 3 :
Which quantity is needed to relate moles with the number of atoms?
Question 6 :
Which of the following electrons take part in a chemical reaction?
Question 7 :
An element $X$ combines with oxygen to form an oxide ${X}_{2}O$. This oxide is electrically conducting. How many electrons would be there in the outermost shell of the element $X$?
Question 9 :
The molecular mass of $CuSO_4.5H_2O$ is:(Atomic mass of $Cu$ $=$ 63.5, $H$ $=$ 1, $O$ $=$ 16, $S$ $=$ 32)<br/>
Question 10 :
How many atoms are represented in$\displaystyle { Na }_{ 2 }{ CO }_{ 3 }\cdot 10{ H }_{ 2 }O$
Question 11 :
How many moles of calcium carbonate $(CaCO_3)$ are present in 20 g of the substance? ($Ca = 40,\ C = 12,\ O = 16$)
Question 17 :
Mass can neither be created nor destroyed. This is in agreement with which law of chemical combination?
Question 20 :
Calculate the number of moles present in $4.9 g$ of ${ H }_{ 2 }S{ O }_{ 4 }$.
Question 22 :
Choose the correct answer from the options given below<br>The formula of iron (III) sulphate is
Question 27 :
Calculate the number of moles present in 24 gm of oxygen gas. (Atomic mass = $16$).<br/>
Question 28 :
When two electrons are removed from helium atom, then resultant entity is defined as?<br/>
Question 30 :
Atoms either donate or accept electrons in their outer shells to attain the stable electronic configuration of :