CBSE Questions for Class 11 Medical Chemistry Some Basic Concepts Of Chemistry Quiz 5 - MCQExams.com

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.
  • increases
  • decreases
  • remains same
  • None of the above
Find the mass percentages (mass %) of Na, H, C, and O in sodium hydrogen carbonate.
  • 30, 20, 45, 5
  • 28, 1, 14, 57
  • 24, 23, 12, 1
  • None of above
Determine the percentage composition of $$K$$ in $$KMnO_4$$.
  • $$31\%$$
  • $$43.58\%$$
  • $$25\%$$
  • $$55\%$$

The law of conservation of mass is in agreement with Dalton's atomic theory.
  • True
  • False
If the % composition of Cl in HCl is 46%, what is the mass of Cl in HCl?
  • 13.3 g
  • 66 g
  • 25 g
  • 16.76 g
Calculate the % composition of Carbon in $$CO_2$$. Molar mass is 44.01.
  • 40%
  • 67%
  • 30%
  • 27%
The mass of a sand and powdered mixture along with a beaker is 56 g. If the mass of the dried mixture is 20 g, find the % composition of the mixture in 100 g?
(weight of beaker = 20 g).
  • 20%
  • 36%
  • 55%
  • 60%

Law of conservation of mass is also known as :
  • Law of indestructibility
  • Law of mass action
  • Law of conservation of energy
  • None of the above

The law of conservation of mass will not be strictly valid unless mass and energy are considered together.
  • True
  • False
The current model of atomic structure is the:
  • Quantum mechanical model
  • Quantum physiochemical model
  • Atomic mass theory
  • None of the above
One volume of nitrogen combines with one volume of oxygen to form two volumes of nitric oxide. Calculate the amount of each reactant required to produce 250 ml of nitric oxide.
  • $$N_2=100 ml, O_2=100 ml$$
  • $$N_2=120 ml, O_2=120 ml$$
  • $$N_2=125 ml, O_2=125 ml$$
  • $$N_2=100 ml, O_2=125 ml$$
Magnesium + Oxygen $$\longrightarrow$$     Magnesium Oxide + Oxygen
 48.6 g        +     50.0 g $$\longrightarrow$$     80.6 g                   +      ? 

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. 
  • 20.6
  • 19.6
  • 18
  • 17.6
The chemical equation is balanced to satisfy one of the following laws in chemical reactions. This law is known as the:
  • law of conservation of mass.
  • law of multiple proportions
  • law of chemical equilibrium.
  • none of these
The matter is neither created nor destroyed during any physical or chemical change. This statement is of the :
  • Law of constant proportion
  • Law of conservation of mass
  • Law of reciprocal proportion
  • Law of multiple proportion
When two molecules of hydrogen react with one molecule of oxygen, the mass of reactants is $$36$$, what is the mass of products?
  • $$18$$
  • $$36$$
  • $$9$$
  • $$32$$
When mass is enclosed in a system and no transfer of material and energy is allowed in or out, it's _____ will never change.
  • quality
  • quantity
  • temperature
  • shape
Which of the following is true with respect to law of conservation of matter?
  • It is also called as law of conservation of mass.
  • Mass of products in a chemical reaction is equal to the mass of reactants.
  • Matter is not perfectly conserved
  • All of the above
Which of the following statement is incorrect for the composition of water?
  • For water, the gravimetric or mass ratio of hydrogen to oxygen is $$1:8$$
  • In water, the ratio of hydrogen and oxygen is $$2:1$$ by volume
  • The ratio in which hydrogen and oxygen combine gives the composition of water.
  • None of the above
Dalton’s atomic theory was based on:
  • Law of chemical combination
  • Mass theory
  • Periodic table
  • None of the above
Combustion of a piece of paper to form ash, water vapour and carbon dioxide follows law of conservation of mass.
  • True
  • False
One atomic mass is equal to
  • $$1.66\times10^{-27}$$ g
  • $$1.66\times10^{-24}$$ g
  • $$1.66\times10^{-23}$$ g
  • $$1.66\times10^{-25}$$ g
The density of a gas is found to be $$1.56{ g }/{ L }$$ at $$745$$ mm pressure and $$65\ ^oC$$. What is the molecular mass of the gas?
  • $$44.2 u$$
  • $$4.42 u$$
  • $$2.24 u$$
  • $$22.4 u$$
Which law is not applicable for a nuclear reaction where large amount of energy is released? 
  • Law of conservation of mass
  • Law of definite proportion
  • Law of multiple proportion
  • Avagrado's law
An organic compound contains $$C, H$$ and $$S$$. The minimum molecular weight of the compound containing $$8\%$$ sulphur is:

[atomic weight of $$S= 32\ amu$$]
  • $$200\ g$$ $$mol^{- 1}$$
  • $$400\ g$$ $$mol^{- 1}$$
  • $$300\ g$$ $$mol^{- 1}$$
  • $$600\ g$$ $$mol^{- 1}$$
If $$10$$ liters of CO gas react with sufficient amount of oxygen for a complete reaction, how many liters of $$CO_2$$ gas will be formed?
  • $$5$$
  • $$10$$
  • $$15$$
  • $$20$$
  • $$40$$
Which one is correct about the concept regarding the number of particles in a mole.
  • Avogadro's number
  • $$P_1V_1=P_2V_2$$
  • $$V_1T_2=V_2T_1$$
  • Dalton's Theory
  • Gay-Lussac's Law
From $$2$$ moles of $$KClO_3$$ by decomposition of all the $$KClO_3$$, how many liters of $$O_2$$ can be produced at STP?
  • $$11.2$$
  • $$22.4$$
  • $$33.6$$
  • $$44.8$$
  • $$67.2$$
A metal nitride contains 28% nitrogen by weight. The molecular formula of metal nitride is $$M_3N_2$$. What is the atomic weight of metal ?
  • 72
  • 64
  • 100
  • 24
$$3.011\times { 10 }^{ 22 }$$ atoms of an element weights $$1.15 $$ g. The atomic mass of the element is :
  • $$23$$ amu
  • $$10$$ amu
  • $$16$$ amu
  • $$35.5$$ amu
It can be shown using mass spectrometry that the ratio of naturally occurring chlorine -35 to its isotope chlorine -37 is 3 :Assuming that no other isotopes existed, what would be the atomic weight of chlorine?
  • $$35.5$$
  • $$37.5$$
  • $$36.6$$
  • None of the above
Number of hydrogen ions present in 10 millionth part of $$1.33\ {cm}^{3}$$ of pure water at $${25}^{o}\ C$$ is:
  • $$6.023$$ million
  • $$60$$ million
  • $$8.01$$ million
  • $$80.23$$ million
One atomic mass unit is equal to?

(Given, mass of one carbon-12 atom $$= 1.992 \times 10^{-23}$$)
  • $$1.66\times 10^{-27}g$$
  • $$1.66\times 10^{-24}g$$
  • $$1.66\times 10^{-23}g$$
  • $$1.66\times 10^{-25}g$$
How many grams of NaOH are required to make $$100$$ grams of a $$5\%$$ solution?
  • $$2$$
  • $$5$$
  • $$20$$
  • $$40$$
  • $$95$$
Which scientist synthesised 1st organic compound in lab?
  • Friedrich Wohler
  • Antoine Lavoisier
  • Robert Boyle
  • Willard Gibbs
Avogadro's number is NOT equal to:
  • the number of atoms in 11.2 L of $$\displaystyle { O }_{ 2 }$$ at STP
  • the number of atoms in 1 mole of $$\displaystyle He$$ at STP
  • the number of electrons in 96,500 coulombs
  • the number of $$\displaystyle { SO }_{ 4 }^{ 2- }$$ ions in 1 L of 0.5 M sulphuric acid
Which of the following expressions is equal to the number of iron ($$Fe$$) atoms present in $$10.0$$ g $$\displaystyle Fe$$ ? (atomic mass of $$\displaystyle Fe$$ = $$55.9$$ amu) 
  • $$ 10\times 55.9\times( 6.022\times { 10 }^{ 23 }) $$ atoms
  • $$\dfrac{( 6.022\times { 10 }^{ 23 })}{10}\times 55.9$$ atoms
  • $$ 10\times \dfrac {( 6.022\times { 10 }^{ 23 } )}{ 55.9}$$ atoms
  • $$\dfrac {55.9}{10} \times ( 6.022\times { 10 }^{ 23 } ) $$
  • $$ \dfrac {10}{ ( 55.9\times 6.022\times { 10 }^{ 23 } )} $$ atoms
How many grams of $$\displaystyle Na$$ are present in $$30$$ g $$\displaystyle NaOH$$?
  • $$10$$ g
  • $$15$$ g
  • $$17$$ g
  • $$20$$ g
  • $$22$$ g
How many grams of $$NaOH$$ are needed to make 100 g of a 5 % solution?
  • $$2$$
  • $$5$$
  • $$20$$
  • $$40$$
  • $$96$$
This is the branch of chemistry dealing with the separation, identification and quantitative determination of the composition of different substances. Name is :
  • Physical chemistry
  • Inorganic chemistry
  • Organic chemistry
  • Analytical chemistry
Which branch of chemistry deals with substances consisting of living organism ?
  • Physical chemistry
  • Biochemistry
  • Organic chemistry
  • Analytical chemistry
All gases have the same number of moles in the same volume at constant T and P is stated by :
  • Boyle's law
  • Charle's law
  • Avogardro's law
  • ideal gas law
  • Dalton's law
How many grams of $$H_2SO_4$$ are there in $$1,000$$ grams of a $$10\%$$ solution? Given $$(1$$ mol of $$H_2SO_4=98$$g$$)$$
  • $$1.0$$
  • $$9.8$$
  • $$10$$.
  • $$98$$
  • $$100$$.
A balanced chemical equation  supports
  • Law of chemical equilibrium
  • Law of conservation of energy
  • Law of conservation of mass
  • None of these
What is the approximate molecular mass of dry air containing 78% N$$_2$$ and 22% O$$_2$$?
  • 48.88
  • 18.88
  • 28.88
  • 38.88
Which law states that in a chemical reaction, the total mass of the products is equal to the total mass of the reactants?
  • Law of constant proportions
  • Law of conservation of energy
  • Law of conservation of mass
  • Law of multiple proportions
State whether true or false:
$$1\ g$$ of $$^{12}C$$ contains $$6.022 \times 10^{23}$$ atoms of the isotope.
  • True
  • False
Barium chloride reacts with sodium sulfate to form barium sulfate and sodium chloride. Then, according to the law of conservation of mass:
  • The total mass of reactants, barium chloride, and sodium sulfate taken is greater than the total mass of products, barium sulfate, sodium chloride formed.
  • The total mass of reactants, barium chloride, and sodium sulfate taken is less than the total mass of products, barium sulfate, sodium chloride formed.
  • The total mass of the reactants is equal to the total mass of products.
  • None of the above
Nitrogen reaction with oxygen to form nitrous oxide.

What will be the volume ratio of the reactants and products of the given reaction?
$$2N_{2}+O_{2}\rightarrow 2N_{2}O$$
  • 1 : 1 : 2
  • 1 : 2 : 2
  • 3 : 1 : 2
  • 2 : 1 : 2
If 11 g of oxalic acid are dissolved in 500 mL of solution (density = 1.1 g mL$$^{-1}$$), what is the mass % of oxalic acid in solution?
  • 1%
  • 2%
  • 3%
  • 4%
Calculate the percentage composition of iron in a ferric oxide ($$Fe_2O_3$$).
(Atomic mass of $$Fe = 56$$)
  • 70% $$Fe$$
  • 30% $$Fe$$
  • 40% $$Fe$$
  • 56.5% $$Fe$$
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