CBSE Questions for Class 11 Medical Chemistry Some Basic Concepts Of Chemistry Quiz 7 - MCQExams.com

Referring to the molecular sketch and table above, choose the option that best describes the percentage of carbon in the molecule, in terms of both atomic composition and mass-percent composition.
528697_c61819ee7b3a4be981d44575879baeef.png
  • Carbon makes up approximately $$25$$% of the atoms, and $$25$$% of the mass.
  • Carbon makes up approximately $$40$$% of the atoms, and $$40$$% of the mass.
  • Carbon makes up approximately $$25$$% of the atoms, and $$40$$% of the mass.
  • Carbon makes up approximately $$40$$% of the atoms, and $$25$$% of the mass.
A student carries out the following reaction in the laboratory:

Sodium carbonate + Copper sulphate $$\rightarrow $$ Copper carbonate + Sodium sulphate

How could you determine the reaction obeyed the law of conservation of mass?
  • Mass of the sample after the reaction is compared to the mass before the reaction begins
  • Mass of the sample as the reaction is run is measured
  • Filtering the reactants
  • Running the reaction in an open system
Consider the four decompositions shown here:
Reaction I: $$Ca(NO_{3})_{2}(s)\xrightarrow {\Delta} CaO(s) + N_{2}O_{5}(g)$$
Reaction II: $$CaSO_{3}(s) \xrightarrow {\Delta} CaO(s) + SO_{2}(g)$$
Reaction III: $$Ca(ClO_{3})_{2}(s) \xrightarrow {\Delta} CaCl_{2}(s) + 3O_{2}(g)$$
Reaction IV: $$CaCO_{3}(s) \xrightarrow {\Delta} CaO(s) + CO_{2}(g)$$
In each case, a solid compound of calcium undergoes thermal decomposition, producing a gaseous product and a calcium containing residual solid.
Assuming equal masses of the four compounds, $$Ca(NO_{3})_{2}, CaSO_{3}, Ca(ClO_{3})_{2}$$, and $$CaCO_{3}$$, are heated in open containers to constant mass, in which case will the mass of solid in the container change by the smallest percentage?
  • Reaction I
  • Reaction II
  • Reaction III
  • Reaction IV
Atom is the word derived from the Greek word atomio, which means:
  • uncutable
  • cutable
  • in between
  • combined
Consider the figure below, in which the blue circles represent atoms of copper metal, atomic mass $$63.5\ amu$$, while the red circles represent atoms in zinc metal, atomic mass $$65.4\ amu$$.
Here are four statements concerning this system. Identify the correct statement or statements.
I. This is a single-phase mixture, with a copper-to-zinc atom ratio of $$3 : 1$$.
II. This is two-phase mixture, with a copper-to-zinc atom ratio of $$8 : 1$$.
III. The mixture is $$80$$% copper, by mass.
IV. This mixture could be an alloy of copper and zinc.
528694.jpg
  • Statement I only.
  • Statement II only.
  • Statement I and III only.
  • Statement I and IV only.
Who arranged elements his periodic table, based upon atomic weight:
  • Thomson
  • Mendeleev
  • Lavoisier
  • Sir Humphrey Davy
A 5% by mass of an aqueous solution of $$A$$ of molar mass 342 g mol$$^{-1}$$ is isotonic with 0.878% by mass of an aqueous solution of another substance B. The molar mass of $$B$$ in g mol$$^{-1}$$ is:
  • 120
  • 180
  • 60
  • 90
Who proposed that equal volumes of gases at the same temperature and pressure have  same number of molecules.
  • Heisenberg
  • Avogadro
  • Dalton
  • Boyle
Which one of the following statements is false?
  • Photochemical smog causes irritation in eyes
  • London smog is a mixture of smoke and fog
  • Photochemical smog results in the formation of PAN
  • London smog is oxidising in nature
Who supported the Four Element Concept of Empedocles?
  • Dalton
  • Avogadro
  • Einstein
  • Aristotle

Radioactivity is the caused by the disintegration of:
  • Atom
  • Ion
  • Molecule
  • Nucleus
A compound $$X_2O_3$$ contains 31.58% oxygen by weight. The atomic weight of $$X$$ is:
  • $$344.66 g/mol$$
  • $$52.00 g/mol$$
  • $$45.01 g/mol$$
  • $$104.0 g/mol$$
At room temperature and pressure, two flasks of equal volumes are filled with $$H_2$$ and $$SO_2$$ separately. Particles which are equal in number, in the two flasks are:
  • atoms
  • electrons
  • molecules
  • neutrons
A sample of potato was ground in a ball mill to give a starch-like molecule of lower molecular weight. the product analysed 0.086% phosphorous if each molecule is assumed to contain one atom of phosphorous, what is the molecule weight of material​
  • 36000
  • 37000
  • 46000
  • 3600
How many tons of $$Zn$$ can be obtained form 10 tons of $$ZnS$$?
  • 5.025
  • 10.487
  • 15.282
  • None of these
Hydrogen combines with chlorine to form HCI. It also combines with sodium to form NaH. If sodium and chlorine also combine with each other, they will do so in the ratio of their masses as:
  • 23 : 35.5
  • 35.5 :23
  • 1 : 1
  • 23 : 1
$$SO_2$$ gas was prepared by
(i) burning sulphur in oxygen,
(ii) reacting sodium sulphite with dilute $$H_2SO_4$$ and
(iii) heating copper with $$conc. H_2SO_4$$. It was found that in each case sulphur and oxygen combined in the ratio of 1 :The data illustrates the law of :
  • conservation of mass
  • multiple proportions
  • constant proportions
  • reciprocal proportions
When $$22.4\ L$$ of $$C_{4}H_{8}$$ at $$STP$$ is burnt completely, $$89.6\ L$$ of $$CO_{2}$$ gas the $$STP$$ and $$72\ g$$ of water are produced. The volume of the oxygen gas the STP consumed in the reaction is closest to 
  • $$89.6\ L$$
  • $$112\ L$$
  • $$134.4\ L$$
  • $$22.4\ L$$
The number of g-atom of oxygen in $$6.02\times { 10 }^{ 24 }$$ $$CO$$ molecule is
  • $$1$$
  • $$0.5$$
  • $$5$$
  • $$10$$
A mixture of calcium and magnesium carbonates weighing 1.4 g was strongly heated until no further loss of weight was perceived. The residue weighed 0.76 g. What percentage of $$MgCO_3$$ was present in the mixture?
  • 20.45
  • 18.55
  • 16.33
  • 22.40
Which of the following is/are correct?
  • One atomic mass unit is a mass unit equal to exactly one -twelfth (1/12th) the mass of one atom of carbon-12.
  • One atomic mass unit is a mass unit equal to exactly one - sixteenth (1/16th) the mass of one atom of oxygen-16.
  • The relative atomic mass of the atom of an element is defined as the average mass of the atom, as compared to 1/12h the mass of one carbon-12 atom.
  • None of the above.
2.0 g mixture of sodium carbonate and sodium bicarbonate on heating to constant mass gave 224 mL of $$CO_2$$ at NTP. The % mass of sodium bicarbonate in the mixture is: 
  • 50
  • 54
  • 80
  • 84
How many grams of $$NaOH$$ will be required to prepare $$500\ g$$ solution containing $$10$$% $$\dfrac {w}{w}NaOH$$ solution?
  • $$100\ g$$
  • $$50\ g$$
  • $$0.5\ g$$
  • $$5.0\ g$$
$$5.0\ g$$ sample of urea when heated with $$NaOBr$$ and $$NaOH$$ gives $$1120\ ml$$ of nitrogen at STP. The percentage purity of the sample is:
  • $$50$$%
  • $$40$$%
  • $$60$$%
  • $$30$$%
The molecular weights of $$O_2$$ and $$N_2$$ are $$32$$ and $$28$$ respectively. At $$15^0$$C, the pressure of $$1$$gm $$O_2$$ will be the same as that of $$1$$ gm $$N_2$$ in the same bottle at the temperature:
  • $$-21^0$$C
  • $$-13^0$$C
  • $$15^0$$C
  • $$56.4^0$$V
The maximum amount of $$Ba{SO}_{4}$$ precipitated on mixing $$20mL$$ of $$0.5M$$ $$Ba{Cl}_{2}$$ with $$20mL$$ of $$1M$$ $${H}_{2}{SO}_{4}$$ is?
  • $$0.25$$ mole
  • $$0.5$$ mole
  • $$1$$ mole
  • $$0.01$$ mole
The number of gram molecule of oxygen in $$6.02 \times 10^{24}$$ CO molecules is :
  • 10 gm molecules
  • 5 gm molecules
  • 1 gm molecules
  • 0.5 gm molecules
What is the relative molecular mass of sodium sulphate? (The relative atomic masses of $$Na, S$$ and $$O$$ are $$23 u, 32 u$$ and $$16 u$$ respectively)
  • 140
  • 142
  • 146
  • 148
Calculate the silver ion concentration in $$0.2\ M$$ solution as $$Ag(NH_{3})_{2}NO_{3} \cdot K_{silver} = 32\times 10^{-9}$$.
  • $$4\times 10^{-2}M$$
  • $$2\times 10^{-3}M$$
  • $$3\times 10^{-3}M$$
  • $$5\times 10^{-2}M$$
The percentage composition of $$Cr$$ in $${ K }_{ 2 }{ Cr }_{ 2 }{ O }_{ 7 }$$ is (Given molar mass of $${ K }_{ 2 }{ Cr }_{ 2 }{ O }_{ 7 }=294.0g$$ $$mol$$)
  • $$60.84$$
  • $$28.54$$
  • $$51.3$$
  • $$35.37$$
A solution has $$0.05\ M - Mg^{+2}$$ and $$0.05M - NH_{3}$$. Calculate the minimum concentration of $$NH_{4}Cl$$ required to prevent only precipitation of $$Mg$$ as $$Mg(OH)_{2}\cdot K_{sp}$$ of $$Mg(OH)_{2} = 9\times 10^{-12}$$ and $$K_{b}$$ of $$NH_{3} = 1.8\times 10^{-5}$$.
  • $$0.057\ M$$
  • $$0.067\ M$$
  • $$0.045\ M$$
  • $$1\ M$$
The concentration of $$OH^-$$ ions in a solution with the $$H^+$$ ions concentration of $$1.3\times 10^{-4}$$M is?
  • $$7.7\times 10^{-4}$$
  • $$1.3\times 10^{-4}$$M
  • $$2.6\times 10^{-8}$$M
  • $$7.7\times 10^{-11}$$M
In carbon disulphide $$(CS_{4})$$, the mass of sulphur in combination with $$3.0\ g$$ of carbon is
  • $$4.0\ g$$
  • $$6.0\ g$$
  • $$64.0\ g$$
  • $$16.0\ g$$
If 100 gm of salt solution contains 20 g of salt dissolved in it, the percentage of the mass of the solution is________.
  • $$10\%$$
  • $$20\%$$
  • $$15\%$$
  • $$25\%$$
Decreasing order of atomic weight is correct of the elements given below?
  • $$Fe > Co > Ni$$
  • $$Ni > Co > Fe$$
  • $$Co > Ni > Fe$$
  • $$Co > Fe > Ni$$
300 gm of 25% w/w solution of solute A is mixed with 400 gm of 40 (w/w) solution of another solute B. What is the w/w percentage of new mixture.
  • 10.71% in A
  • 35% in B
  • 25% in A
  • 40% in B
A solution containing 4.2 g of KOH and $$Ca(OH)_2$$ is neutralized by an acid. If it consumes 0.1 equivalent of acid, the % of KOH in the original sample is: 
  • 15%
  • 25%
  • 35%
  • 45%
Sodium reacts with excess oxygen to form sodium oxide.A student wants to prepare 1.24 g of sodium oxide.While doing the calculations, he uses atomic number of sodium instead of obtained due to this mistake?
  • $$11\%$$
  • $$23\%$$
  • $$48\%$$
  • $$60\%$$
The weight of mixture containing HCl and $$H_2SO_4$$ is $$0.1$$g on treatment with an excess of an $$AgNO_3$$ solution, reacted with this acid mixture gives $$0.1435$$g of AgCl, weight percentage of $$H_2SO_4$$ in mixture is:
  • $$36.5$$
  • $$63.5$$
  • $$50$$
  • $$80$$
Two organic compounds $$\underline {R}$$ and $$\underline {S}$$, both containing only $$C$$ and $$H$$ yield on analysis, the same percentage composition by weight.
$$C = (12/ 13) \times 100$$% and $$H = (1/13)\times 100$$%.
$$\underline {R}$$ decolourises $$Br_{2}$$ - water but $$\underline {S}$$ does not.
  • $$C_{2}H_{2}, C_{6}H_{6}$$
  • $$C_{6}H_{6}, C_{2}H_{2}$$
  • $$C_{2}H_{4}, C_{2}H_{6}$$
  • $$C_{2}H_{2}, C_{3}H_{8}$$
A mixture contains equimolar quantities of carbonates of two bivalent metals. One metal is present to the extent of $$13.5\%$$ by weight in the mixture and $$2.58$$g of the mixture on heating leaves a residue of $$1.35$$g. What percentage by weight of the other metal is there?
  • $$31.6$$
  • $$21.3$$
  • $$19.2$$
  • $$17.8$$
$$\text{0.80 g}$$ of impure $$(NH_4)_2SO_4$$ was boiled with $$100 ml$$. of a $$\text{0.2 N NaOH}$$ solution till all the $$NH_3(g)$$ evolved.The remaining solution was diluted to $$\text{250 mL.25 mL}$$ of this solution was neutralized using $$5 mL$$ of a $$\text{0.2 n H_2SO_4}$$ solution.The percentage purity of the $$(NH_4)_2SO_4$$ sample is 
  • $$82.5$$
  • $$72.5$$
  • $$62.5$$
  • $$17.5$$
One mole of any substance contains $$6.022\times 10^{23}$$ atoms/molecules. Number of molecules of $$H_2SO_4$$ present in $$100$$mL of $$0.02$$M $$H_2SO_4$$ solution is __________.
  • $$12.044\times 10^{20}$$ molecules
  • $$6.022\times 10^{23}$$ molecules
  • $$1\times 10^{23}$$ molecules
  • $$12.044\times 10^{23}$$ molecules
$$500mL$$ of a glucose solution contains $$6.02\times { 10 }^{ 22 }$$ molecules. The concentration of the solution is
  • $$0.1M$$
  • $$1.0M$$
  • $$0.2M$$
  • $$2.0M$$
How many moles of electron weight one kilogram?
  • $$6.023\ \times \ { 10 }^{ 23 }$$
  • $$\dfrac { 1 }{ 9.108 } \times \ { 10 }^{ 31 }$$
  • $$\dfrac { 6.023 }{ 9.108 } \times \ { 10 }^{ 54 }$$
  • $$\dfrac { 1 }{ 9.108\ \times \ 6.023 } \times \ { 10 }^{ 8 }$$
The weight of $$AgCl$$ precipitated when a solution containing $$5.85\ g$$ of $$NaCl$$ is added to a solution containing $$3.4\ g$$ of $$AgNO_3$$ is:
  • $$28\ g$$
  • $$9.25\ g$$
  • $$2.870\ g$$
  • $$58\ g$$
Sodium bicarbonate, $$NaHCO_{3}$$, can be purified by dissolving it in hot water $$(60^{\circ}C)$$, filtering to remove insoluble impurities, cooling to $$0^{\circ}C$$ to precipitate solid $$NaHCO_{3}$$, and then filtering to remove the solid, leaving soluble impurities in solution. Any $$NaHCO_{3}$$ that remains in the solution is not recovered. The solubility of $$NaHCO_{3}$$ in hot water at $$60^{\circ}C$$ is $$164\ g/litre$$ and is $$69\ g/litre$$ in cold water at $$0^{\circ}C$$. What is the percentage yield of $$NaHCO_{3}$$, when it is purified by this method?
  • $$55.34$$%
  • $$42.07$$%
  • $$69$$%
  • $$31$$%
$$H_3AO_4$$ has 31.6% of "A" by mass. The atomic mass of the atom "A" is:
  • 17
  • 31
  • 35.5
  • 40
What do carbon credits signify?
  • Credits given in the course of carbon products sales
  • Entitlements to emit certain quantity of green house gases
  • Permissible amount of Carbon dioxide in the atmosphere
  • The extent of carbon required to ensure sustainable development
The leaves of a green bean plant were exposed to carbon dioxide containing the radioactive isotope of carbon $$^{14}C$$ for few hours in sunlight. A section of the plant's stem was then immediately obtained and placed on an X-ray film that blackens where exposed to radioactivity. The following diagrams show the cross-section of the stem, and the resulting autoradiograph. Why is structure $$P$$ shown radioactive?
811553_3b0f3b5b93ad4f07b8f4b3149deadf00.jpg
  • $$P$$ transported radioactive carbohydrates from leaves to other plant parts
  • Radioactive carbon dioxide gets dissolved in cell sap and is transported along with water and minerals by structure $$P$$
  • The radioactive carbon is incorporated only in the tissues constituting structure $$P$$
  • None of these
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