Question 2 : <p><span>In the formation of iron sulphide, by heating iron and sulphur, the mass of iron(II) sulphide __________ when compared with a total mass of iron and sulphur.</span></p>
Question 4 :
French chemist ____ laid the foundation to the scientific investigation of matter by describing that substances react by following certain laws.<br/>
Question 15 :
One mole is equal to number of atoms as contained in:
Question 17 : The % of Copper and Oxygen in samples of CuO obtained by different methods were found to be the same. <div><span>This proves the law of:</span><br/></div>
Question 20 :
Who laid the foundation of chemical sciences by experimentally establishing laws of chemical combination along with other scientists?
Question 25 :
Which one of the following scientist's proposed the law of conservation of mass?<span><br/></span>
Question 27 :
The laws of chemical combination formed on the basis of :
Question 28 :
Law of constant composition is also called as the law of :
Question 30 :
The weight of gaseous mixture containing $6.02 \times 10^{23}$ molecules of nitrogen and $3.01\times 10^{23}$ molecules of sulphur dioxide is:<br/>
Question 31 :
Which has more number of atoms: $100$ g of $N_2$ or $100$ g of $NH_3$?<br>
Question 32 : The number of moles of '$X$ ' atoms in $93$ gm of 'X' are:<div>(Molecular Weight of $X =31$ g/mole)</div>
Question 33 :
Which of the following contains the largest mass of hydrogen atoms?
Question 34 :
Find number of oxygen atoms present in $100 \ mg$ of $CaCO_3$.<br/>(Atomic Mass of $Ca=40 \ u, \ C=12 \ u, \ O=16 \ $)
Question 35 :
<span> The number of atoms in one mole of a substance is equal to ................ ?</span><br/>
Question 37 : <div><span>Magnesium + Oxygen $\longrightarrow$ Magnesium Oxide + Oxygen</span><br/></div> 48.6 g + 50.0 g $\longrightarrow$ 80.6 g + ? <br/><br/><div>Predict the mass of oxygen that will be left over after the reaction of 48.6 grams of magnesium with 50.0 grams of oxygen. <br/></div>
Question 38 : <p><span>A sealed tube containing phosphorus was weighed and heated carefully. After completion of the reaction, the tube was re-weighed under similar conditions. The weight of the tube will:</span></p>
Question 39 :
Mass can neither be created nor destroyed. This is in agreement with which law of chemical combination?
Question 40 : <div><div>Four different experiments were conducted in the following ways-</div><div><br/></div><div>I) $3g$ of carbon was burnt in $8g$ of oxygen to give $11g$ of $CO_2$.</div><div><br/></div><div>II) $1.2g$ of carbon was burnt in air to give $4.2g$ of $CO_2$.</div><div><br/></div><div>III) $4.5g$ of carbon was burnt in enough air to give $11g$ of $CO_2$.</div><div><br/></div><div>IV) $4g$ of carbon was burnt in oxygen to form $30.3g$ of $CO_2$.</div></div><div><br/></div>Law of constant proportions is illustrated in which of the following experiment(s)?
Question 41 :
If the ratio of the atoms by mass is altered then:
Question 42 :
Which of the following statement (s) is/are correct about the Avogadro's number ?
Question 44 :
The ratio of mass of nitrogen and oxygen in nitric oxide is:
Question 45 :
Which of the following is a suitable example for illustrating the law of conservation of mass? (Atomic mass of O = 16 u; H = 1 u)
Question 46 :
Which law is not applicable for a nuclear reaction where large amount of energy is released?
Question 47 :
<span>Law of definite proportion does not apply to nitrogen oxide because:</span>
Question 49 :
What is the mass (in grams) of $3$ moles of $N$ atom?
Question 52 :
A solution of copper oxide was prepared by heating, igniting and precipitation. Which of the following method will give higher ratio of copper oxide?<br>
Question 53 : <p><span>A 78.0 g sample of an unknown compound contains 12.4 g of hydrogen. What is the percent by mass of hydrogen in the compound?</span></p>
Question 54 :
The number of atoms in 0.1 mol of a triatomic gas is:
Question 55 :
In an experiment, $2.4\ g$ of iron oxide on reduction with hydrogen gave $1.68\ g$ of iron. In another experiment, $2.69\ g$ of iron oxide gave $1.88 \ g$ of iron on reduction. Which law is illustrated from the above data?
Question 56 : 3 g of a hydrocarbon on combustion in excess of oxygen produces 8.8 g of $CO_2$ and 5.4 g of $H_2O$. <div><br/></div><div>The data illustrates the law of :</div>
Question 58 :
Total number of atoms in 20 g of calcium carbonate is ________.<br/>
Question 60 :
Which law states that the total mass of the reactants is equal to the total mass of the products <span>in a chemical reaction</span>?
Question 61 :
$10\ { dm }^{ 3 }$ of ${ N }_{ 2 }$ gas and $10\ { dm }^{ 3 }$ of gas X at the same temperature contain the same number of molecules. The gas X is
Question 62 :
A compound contains $10^{-2}\%$ of phosphorus. If the atomic mass of P is $31$, then the molecular mass of the compound having one phosphorous atom per molecule is:
Question 63 :
How many moles of oxygen gas can be produced during electrolytic decomposition of $180 \ g$ of water?
Question 66 :
14 g of element X combine with 16 g of oxygen. On the basis of this information, which of the following is a correct statement?
Question 68 :
If Avogadro's number would have been $1\times { 10 }^{ 23}$, instead of $6.02\times { 10 }^{ 23 }$ then mass of one atom of $_8^{16}O$ would be:
Question 69 : The number of nitrogen atoms in $21$ g of nitrogen are:<div>(Molecular Weight of Nitrogen $=14$ g/mole)</div>
Question 70 :
4.88 g of $KClO_3$ when heated produced 1.92 g of $O_2$ and 2.96 g of KCl. Which of the following statements regarding the experiment is correct?
Question 71 :
Hydrogen combines with nitrogen in a 3:14 weight ratio to form ammonia. If every molecule of ammonia contains three atoms of hydrogen and one atom of nitrogen, an atom of nitrogen must weigh :
Question 72 :
The number of atoms present in $10$ gms of $CaCO_{3}$ is:<br/>
Question 73 :
Find the accurate statement for the significance of Avogadro's number ?<br/>
Question 75 :
An ion is produced as a result of gain or loss of electrons by an atom. <span> In $Au^{3+}$ ion, 3 electrons are ___________by $Au$ atom.</span>
Question 76 :
When two molecules of hydrogen react with one molecule of oxygen, the mass of reactants is $36$, what is the mass of products?
Question 77 :
The mass of $Na$ present in 11.7 g of $NaCl$ is:
Question 78 :
A sample of $CaCO_3$ has Ca - 40%, C = 12% and O = 48%. If the law of constant proportions is true, then the mass of Ca in 5 g of $CaCO_3$ from another source will be:<span><br/></span>
