Question 1 :
The result of the operation 2.5 X 1.25 should be which of the following on the basis of significant figures?
Question 3 :
Assertion: The number of significant figures in 507000 is three.<br/>
Reason: In 507000, all the zeros are significant. 
Question 4 :
On dividing 0.46 by 15.374, the actual answer is 0.02992. The correctly reported answer will be:<br/>
Question 5 :
Assertion: Significant figures for $0.200$ is $3$ whereas for $200$ it is $1$
Reason: Zero at the end or right of a number are significant provided they are not on the right side of the decimal point.
Question 11 :
If repeated measurements give values close to one another, the number is:
Question 13 : Two student performed the same experiment separately and each one of them recorded two readings of mass which are given below. Correct reading of mass is $3.0\ g$. One the basis of given data, mark the correct option out of the following statement.<br><table class="wysiwyg-table"><tbody><tr><td>Student</td><td>Reading</td></tr><tr><td>$A$</td><td>$3.01\quad 2.99$</td></tr><tr><td>$B$</td><td>$3.05\quad 2.95$</td></tr></tbody></table>
Question 16 :
The prefix used for denoting an order of magnitude of ${ 10 }^{ 6 }$ is:<br/>
Question 17 :
According to the Avogadro's Law, equal volumes of two different gases, under same conditions of temperature and pressure, contain equal number of:<br/>
Question 18 :
Which statement is linked with the idea that two identical containers filled with different gases will contain the same number of particles?
Question 19 :
Chemical reactions such as redox reactions involve transfer of ___________one species to other species.<br/>
Question 20 :
Which of the following statements is the most accurate with regard to the significance of Avogadro's number, $6.02 \times 10^{23}$ ?
Question 21 :
Two samples of lead oxide were separately reduced to metallic lead by heating in a current of hydrogen. The weight of lead from one oxide was half the weight of lead obtained from the other oxide. The data illustrates. <br>
Question 22 :
Who laid the foundation of chemical sciences by establishing two important laws of chemical combination ?
Question 23 :
______ is a branch of chemistry in which quantitative relationship between masses of reactants and products are established. 
Question 24 :
French chemist ____ laid the foundation to the scientific investigation of matter by describing that substances react by following certain laws.<br/>
Question 26 :
The number of molecules in 1 L of oxygen and 1 L of nitrogen at STP will be:
Question 29 :
Matter is neither created nor destroyed during any physical or chemical change. This statement is :
Question 30 :
The chemical equation are balanced to satisfy one of the following laws in chemical reactions. This law is known as:
Question 31 :
The energy released (exothermic) or adsorbed (endothermic) in a chemical reaction is a result of:<br/>
Question 32 :
A chemical equation is balanced in accordance with the law of
Question 33 :
Which of the following is true with respect to Law of Conservation of matter?
Question 34 :
When mass is enclosed in a system and none is allowed in or out, it's _____ will never change.
Question 35 :
A balanced chemical equation is in accordance with the law of conservation of masses___________.
Question 37 :
Which one of the following laws directly explains the law of conservation of mass?<br/>
Question 38 :
Which gas law relates the volume of a gas to the number of molecules of the gas?<br/>
Question 39 :
Find the total number of pennies in a tenth of a mole of pennies.
Question 40 :
A sample of ammonia has a mass of $51.1g$. How many molecules are in this sample?
Question 41 :
How many moles are present in $6.023\times 10^{22}$ molecules of $CO_2$?<br>
Question 42 :
What is the volume of $3.0\times {10}^{20}$ molecules of $HCl (g)$?
Question 43 :
The critical volume of a gas is 0.036 $lit. mol^{-1}$. The radius of the molecule will be (in cm):<br/>(Avogadro Number = $6 \times 10^{23}$)<br/>
Question 44 :
Law of definite proportion does not apply to nitrogen oxide because:
Question 45 :
If the ratio of the atoms by mass is altered then :
Question 47 :
In a compound the ratio of the atoms or element by mass remains always same irrespective of :<br/>
Question 48 :
Different samples of water were found to contain hydrogen and oxygen in the ratio of 1 : 8. This shows the law of:<br/>
Question 49 :
The ratio of mass of nitrogen and oxygen in nitric oxide is in :
Question 50 :
The % of Copper and Oxygen in samples of CuO obtained by different methods were found to be the same. This proves the law of:<br/>
Question 51 :
Assertion: $1.231$ has three significant figures.
Reason: All numbers right to the decimal point are significant.
Question 52 :
In ammonia, nitrogen and hydrogen always combine in $14:3$ ratio by mass. This is in agreement with :
Question 53 :
3 g of a hydrocarbon on combustion in excess of oxygen produces 8.8 g of $CO_2$ and 5.4 g of $H_2O$. <br/>The data illustrates the law of :
Question 54 :
The number of significant figures in $N_{0}=6.022\times 10^{23}$ i.e., Avogadro's number, is :<br/>
Question 55 :
Number of water molecules in one litre of pure water is :
Question 56 :
Assertion: Pure water obtained from different states of India always contains hydrogen and oxygen in the ratio of $1:8$ by mass.
Reason: Total mass of reactants and products during chemical change is always the same.
Question 57 :
The volume occupied by 7 grams of nitrogen gas at STP is:<br/>
Question 59 :
How many atoms of hydrogen are present in $7.8\ g$ of $Al{(OH)}_{3}$?
Question 60 :
Potassium combines with two isotopes of chlorine $(^{35} Cl\,\, and\,\, ^{37}Cl)$ respectively to form two samples of $KCl$ Their formation follows the law of:
Question 61 :
Water gas is an equi-molar mixture of hydrogen and carbon monoxide. If 250 litres of water gas is burnt in air. Assuming both reactants and products are at same temperature and pressure, the volume of $O_2$ required is _________.<br/>$2CO + O_2 \rightarrow 2CO_2; 2H_2 + O_2 \rightarrow 2H_2O$
Question 63 :
Nitrogen reaction with oxygen to form nitrous oxide.<br/>What will be the volume ratio of the reactants and products of the given reaction?<br/>
Question 68 :
When $3\ g$ of carbon is burnt in $8\ g$ of oxygen, $11 g$ of carbon dioxide is produced. What mass of carbon dioxide will be formed when $3\ g$ of carbon is burnt in $50\ g$ oxygen?
Question 69 :
Which choice shows the answer to the following mathematical operation with the correct number of significant figures?<br/>$\dfrac{12.55}{3.0} =4.18333$
Question 71 :
What is the mass of $6.022\times { 10 }^{ 23 }$ formula units of ${({NH}_{4})}_{2}{SO}_{4}$?
Question 72 :
Total number of atoms present in 34 g of $NH_3$ is:
Question 73 :
A sample was weighted using two different balances. The result's were (i) $3.929g$ (ii) $4.0g$. How would the weight of the sample be reported?
Question 74 :
A vessel contains N molecules of oxygen at a certain temperature and pressure. How many molecules of sulphur dioxide can the vessel accommodate at the same temperature and pressure.
Question 75 :
In Haber's process, the volume of ammonia relative to the total volume of reactants at STP is:<br/>
Question 76 : <p>The law of conservation of mass will not be strictly valid unless mass and energy are considered together.</p>
Question 77 :
Given the numbers: $161$ cm; $0.161$ cm; $0.0161$ cm. The number of significant figure for three numbers is: 
Question 81 :
Which choice shows the answer to the following mathematical operation with the correct number of significant figures?<br/>$2.8\times 8.96 = ? $
Question 83 :
Assertion: In a chemical reaction, the sum of the masses of the reactants and products remains unchanged.
Reason: According to the law of conservation of mass, matter can neither be created nor destroyed
Question 84 :
Chemical compounds are formed to have constant composition irrespective of their
Question 85 :
If water samples are taken from the sea, rivers, clouds, lakes or snow, they will be found to contain hydrogen and oxygen in the ration of $1 : 8$. This clearly demonstrates the law of ?
Question 86 :
Three successive measurements in an experiment gave value $10.9, 11.4042$ and $11.42$ the correct way of reporting the average value is:
Question 87 :
A sample of pure carbon dioxide, irrespective of its source contains 27.27 % carbon and 72.73% oxygen. The given data supports: 
Question 88 :
Three containers A, B and C of equal volume, contain $N_2$, $NO_2$ and $CO_2$ respectively, at the same temperature and pressure. The ascending order of their masses is:
Question 90 :
Assuming all volumes measured at the same temperature and pressure, state the volume ratio of the reactants and products when ethane burning in oxygen to give carbon dioxide and steam.
Question 91 :
In an experiment, 2.4 g of iron oxide on reduction with hydrogen gave 1.68 g of iron. In another experiment, 2.9 g of iron oxide gave 2.09 g of iron on reduction. Which law is illustrated from the above data?
Question 92 :
Assertion: One mole of oxygen gas occupies $22.4\ l$ volume at STP.
Reason: Volume of a gas depends on temperature and pressure and also nature of gas.
Question 93 :
Given the numbers $786$, $0.786$ and $0.0786$. The number significant figures for the numbers is :<br/>
Question 94 :
A vessel contains X number of molecules of hydrogen gas at a certain temperature and pressure. Under the same conditions of temperature and pressure, how many molecules of nitrogen gas would be present in the same vessel?
Question 97 :
The actual product of 4.327 and 2.8 is 12.1156. The correctly reported answer will be :<br/>
Question 98 :
Assertion: Atoms can neither be created nor destroyed.
Reason: Under similar condition of temperature and pressure, equal volume of gases does not contain equal number of atoms.
Question 100 :
Statement I: The number $5,007$ has three significant figures<br>Because<br>Statement II: Zeros between non-zero digits are significant
Question 102 :
The number of $H_{3}O^{+}$ ions present in 10ml of water at $25^{\circ}C$ is:<br/>
Question 105 :
40 ml of mixture of $C_{2}H_{2}$ and CO is mixed with 100 ml of $O_{2}$ gas and the mixture is exploded. The residual gases occupied 104 ml and when these are passed through KOH solution, the volume becomes 48ml. All the volume are at same the temperature and pressure. Determine the composition of the original mixture.
Question 106 :
What volume of hydrogen at NTP will be liberated when 3.25 g of zinc completely dissolve in dilute HCl? <br/>[At. mass of Zn = 65]<br/>
Question 107 :
$1.375$ g of cupric oxide was reduced by heating in a current of hydrogen and the weight of copper obtained was $1.098$ g. In another experiment, $1.179$ g of copper was dissolved in nitric acid and the resulting solution was evaporated to dryness. The residue of copper nitrate when strongly heated was converted into $1.4476$ g of cupric oxide. The result of this process show :
Question 108 :
A measured mass of an unreactive metal was dropped into a small graduated cylinder half filled with water. The following measurement were made:<br/>Mass of metal $= 25.200\ g$<br/>Volume of water before addition of metal $=12.5\ mL$<br/>Volume of water after addition of metal $= 15.0\ mL$<br/>The density of the metal should be reported as:
Question 109 :
Assertion: STATEMENT 1: $SO_{2}$ obtained either by the oxidation of $H_{2}S$ or decomposition of sulphate salt contains sulphur and oxygen in the mass ratio $1 : 2.$
Reason: STATEMENT 2: $S_{(s)}+O_{2(g)}\rightarrow SO_{2(g).}$
Question 110 :
20 ml of a mixture of $C_{2}H_{2}$ and CO was exploded with 30ml of oxygen. The gases after the reaction had a volume of 34ml. On treatement with $KOH$, 8ml of oxygen remained. Calculate the composition of the mixture.
Question 111 :
Statement 1: At the same temperature and pressure, 1 L of hydrogen gas and  1 L of neon gas have the same mass.<br/>Statement 2: Equal volumes of ideal gases at the same temperature and pressure contain the same number of moles.
Question 112 :
At NTP, 10 litre of hydrogen sulphide gas reacted with 10 litre of sulphur dioxide gas. The volume of gas, after the reaction is complete, would be:
Question 113 :
Zinc sulphate contains $22.65$% $Zn$ and $43.9$% ${H}_{2}O$. If the law of constant proportions is true, then the mass of zinc required to give $40g$ crystal will be:
Question 114 :
The value of observed and calculated molecular weight of silver nitrate is 92.64 and 170 respectively the degree of dissociation of silver nitrate is:
Question 115 :
In a gaseous reaction of the type, $aA + bB \rightarrow  cC + dD$, which is wrong?<br/>
Question 116 :
$14$ g of element X combines with $16$ g of oxygen. On the basis of this information, which of the following is a correct statement?
Question 117 :
Which of the following is a suitable example for illustrating the law of conservation of mass? (Atomic mass of $O= 16,H= 1$ g/mole)<br/>
Question 118 : <p><b> 60 g</b> of a compound on analysis produced <b>24 g </b><b> </b><b>carbon</b>, <b>4 g </b><b> </b><b>hydrogen</b>, and <b> 32 g</b><b> </b><b>oxygen</b>. The empirical formula of the compound is</p>
Question 119 :
Which of the statements are true about the law of chemical combination?<br>
Question 120 :
A salt is formed due to the reaction between an oxy acid containing chlorine and a base containing a monovalent metal of atomic mass $x$. The number of oxygen atoms in one molecule of the acid is more than the corresponding 'ic' acid. Calculate the molecular mass of the salt.
Question 121 :
Hydrogen and oxygen combine to form $H_{2}O_{2}$ and $H_{2}O$ containing $5.93\%$ and $11.2\%$ the respectively. The data illustrates the:
Question 122 :
$CaCO_3 + 2HCl \rightarrow CaCl_2 + H_2O + CO_2$<br/>The volume of CO$_2$ gas formed when 2.5 g calcium carbonate is dissolved in excess hydrochloric acid at 0$^o$C and 1 atm pressure is:[1 mole of any gas at 0$^o$C and 1 atm pressure occupies 22.414 L volume].
Question 123 :
$10$ mL of hydrogen combines with $5$ mL of oxygen to yield water. When $200$ mL of hydrogen at STP is passed over heated $CuO$, the $CuO$ loses $0.144$ g of its weight. State the law illustrated by these chemical combinations.
Question 124 :
Percentage purity of a sample of gold is $85\%$. How many atoms of gold are present in its $1$ gram sample? (Atomic mass of gold $=197$u).
Question 125 :
In the relation, $p={ \dfrac { \alpha  }{ \beta  } { e }^{ -\dfrac { \alpha Z }{ k\theta  }  } }$ <br/>$P$ is pressure, $Z$ is distance, $k$ is Boltzmann's constant and $\theta$ is the temperature. The dimensional formula of $\alpha$ will be:
Question 126 :
Which of the following statements is correct about the reaction given below?<br>$\displaystyle 4Fe\left ( s \right )+3O_{2}\left ( g \right )\rightarrow 2Fe_{2}O_{3}\left ( g \right )$<br>
Question 127 :
The vapours of organic compound was burnt in oxygen. Equal volume of both gaseous substance were taken at same pressure and temperature. After the reaction, the system was returned to the original condition and it turn out that its volume has not changed. The product of combustion contain 50% $CO_{2}$(g) and 50% $H_{2}O$(g) by volume and no other gas. Find the molecular weight of organic compound (in gram/mol) in question.
Question 128 :
Assertion: Carbon monoxide is considered a compound but carbon and oxygen as elements.
Reason: A chemical element is a pure chemical substance consisting of a single type of atom distinguished by its atomic number, which is the number of protons in its atomic nucleus. While the compound is composed of two or more separate elements.
Question 129 :
If $224ml$ of triatomic gas has a mass of $1g$ at $273K$ and $1atm$ pressure, then the mass of one atom is-
Question 130 :
10 ml of CO is mixed with 25 ml air having  20 per cent $O_{2}$ by volume. What would be the final volume if none of CO and $\displaystyle\: O_{2}$ is left after the reaction?
Question 131 :
Calculate the volume of $CO_{2}$ evolved by the combustion of $50$ ml of a mixture containing $40$ per $C_{2}H_{4}$ and $60$ per $CH_{4}$ (by volume).
Question 132 :
The mass of residue left after strongly heating 1.38 g of silver carbonate will be:
Question 133 :
A student performs a titration with different burettes and finds titre values of $25.2$ ml, $25.25$ ml and $25.0$ ml. The number of significant figures in the average titre value is :
Question 134 :
When 100 ml of a $O_{2} - O_{3}$ mixture was passed through turpentine, there was the reduction of volume by 20 ml. If 100ml of such a mixture is heated, what will be the increase in volume?
Question 135 :
10 ml of a mixture of $CH_{4}, C_{2}H_{4}$ and $CO_{2}$ were exploded with excess of air. After explosion, there was contraction on cooling of 17 ml and after treatment with KOH, there was further reduction of 14 ml. What is the composition of the mixture?
Question 136 :
The mass of oxygen with which 13.5 g of aluminium will completely react is:
Question 137 :
Which units of pressure are needed if you are going to use 0.0821 as your ideal gas constant?
