• info@ourselfstudy.com
  • 91-7349044845
  • Sign In
  • Register
  • Admission
wa

20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample ?

(A)

60

(B)

84

(C)

75

(D)

96

NEET - Medical UG-2015 Medium

Answer & Solution:

Answer: 84 %

The chemical reaction is \(MgCO_{3}\overset{heat}{\rightarrow}MgO+CO_{2}\)  

molecular weight of Magnesium carbonate = 84 g/mol

molecular weight of Magnesium Oxide =40 g/mol

Now  1 mol carbonate produces 1 mol of oxide ,

So , 20 g or 0.238 mol of Magnesium Carbonate must produce 0.238 mol of Oxide if it is 100 % pure 

Now , moles of Oxide produced = 0.2 mol 

So , percentage purity of Magnesium Carbonate is =\((0.2\div 0.238)\times 100\)  = 84 %

Try for Free

Try for free

Other Questions of the same topic

Q1:

If \(3.01×10^{20}\) u molecules are removed from 98mg of \(H_2SO_4\), then number of moles of \(H_2SO_4\) left are

(A)

\(0.1×10^{-3}\) mol

(B)

\(9.95×10^{-2}\) mol

(C)

\(0.5×10^{-3}\) mol

(D)

\(1.66×10^{-3}\) mol

K-CET-2017 Medium

Q2:

The molarity of urea (molar mass 60 g \(mol^{-1}\)) solution by dissolving 15 g of urea in 500 \(cm^{3}\) of water is

(A)

\(2 \,mol\,\,dm^{-3}\)

(B)

\(0.5 \,mol\,\,dm^{-3}\)

(C)

\(0.125 \,mol\,\,dm^{-3}\)

(D)

\(0.0005 \,mol\,\,dm^{-3}\)

MHT-CET-2018 Medium

Q3:

If avogadro number N\(\large _{A}\), is changed from 6.022 × 10\(\large ^{23}\) mol\(\large ^{-1}\) to 6.022 × 10\(\large ^{20}\) mol\(\large ^{-1}\), this would change :

(A)

the ratio of chemical species to each other in a balanced equation

(B)

the ratio of elements to each other in a compound

(C)

the definition of mass in units of grams

(D)

the mass of one mole of carbon

NEET - Medical UG-2015 Medium

Biology Physics

Get Questions, Answer & Solutions for NEET

₹ 100

Your Success is our only Objective

We ensure your improvement in performance by providing outstanding online test preparation service with the best quality of question bank for your course.

Test Preparation

About OurSelfStudy

Newsletter

Subscribe monthly news letter with booster tips

Copyright © 2020-2024 www.OurSelfStudy.com All Rights Reserved