CBSE Questions for Class 11 Medical Chemistry Some Basic Concepts Of Chemistry Quiz 6 - MCQExams.com

Calculate the number of iron atoms in a piece of iron weighing $$2.8 g$$. (Atomic mass of iron $$=56$$)
  • $$30.11\times { 10 }^{ 23 }$$ atoms
  • $$3.11\times { 10 }^{ 23 }$$ atoms
  • $$3.0115\times { 10 }^{ 22 }$$ atoms
  • $$301.1\times { 10 }^{ 23 }$$ atoms
State whether true or false:
1 g of $$^{12}C$$ contains $$6.022 \times 10^{23}$$ atoms of the isotope.
  • True
  • False
8 g of a solute is dissolved in 92 g of solvent. If the density of solution is 2 g ml$$^{-1}$$, find the weight-volume percentage.
  • 10 g ml$$^{-1}$$
  • 12 g ml$$^{-1}$$
  • 16 g ml$$^{-1}$$
  • 15 g ml$$^{-1}$$
Solubility of a solute is $$S$$. Find its percentage by weight.
  • $$\dfrac{200S}{S + 100}$$
  • $$\dfrac{50S}{S + 100}$$
  • $$\dfrac{100S}{S + 100}$$
  • None of these
A solution with a weight percentage of sodium hydroxide of 9% is prepared by adding the following mass of water (in grams) to 300 grams of that solution with a weight percent of $$NaOH$$ of 15%.
  • 100 g
  • 150 g
  • 200 g
  • 250 g
How many mL of sulphuric acid of density 1.84 g mL$$^{-1}$$ containing 95.6 mass % of $$H_2SO_4$$ should be added to one litre of 40 mass % solution of $$H_2SO_4$$ of density 1.31 g mL$$^{-1}$$ in order to prepare 50 mass % solution of sulphuric acid of density 1.40 g mL$$^{-1}$$?
  • 66.2 ml
  • 55.2 ml
  • 95.5 ml
  • 105.2 ml
What weight of sodium contains the same number of atoms as those in $$8$$ grams of oxygen?
  • $$10.5 g$$
  • $$13.5 g$$
  • $$11.5 g$$
  • $$14.2 g$$
A student has only 200 g of valuable solvent and wishes to make a solution of 20% by weight from solute $$A$$. How many grams of $$A$$ is weighed out?
  • 50 grams
  • 250 grams
  • 20 grams
  • 30 grams
The value of the Avogadro constant is:
  • $$6.022 \times 10^{13}$$
  • $$6.022 \times 10^{22}$$
  • $$6.022 \times 10^{23}$$
  • $$6.022 \times 10^{24}$$
If 11g 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 nitrogen in urea ($$H_2NCONH_2$$).
  • 46.6% $$N$$
  • 43.6% $$N$$
  • 44.6% $$N$$
  • 42.6% $$N$$
The number of moles of NaCl in 3 litres of 3 M solution is:
  • 1
  • 3
  • 9
  • 27
What is the percentage composition of the elements in ammonia ($$NH_3$$)? 
$$(N = 14,\ H = 1)$$
  • $$N= 82.35$$ %, $$H=17.65$$ %
  • $$N= 81.35$$ %, $$H=18.65$$ %
  • $$N= 80.35$$ %, $$H=19.65$$ %
  • $$N= 42.35$$ %, $$H=57.65$$ %
What is the mass of a mole of water containing 50% of heavy water $$(D_2O)$$ ?
  • $$19\ g$$
  • $$18\ g$$
  • $$20\ g$$
  • $$21\ g$$
A solution is prepared by dissolving 5.64 g of glucose in 60 g of water. Calculate the mass percent of glucose. 
  • 8.59%
  • 6.85%
  • 9.34%
  • 3.59%
What are the percentage compositions of hydrogen and oxygen in water $$(H_2O)$$? 
$$(H =1,\ O = 16)$$ 
  • 11.1, 88.9
  • 11.2, 88.8
  • 11, 89
  • 11.3, 88.7
A $$250$$ g sample of a hydrated salt was heated at $${110}^{o}C$$ until all water was driven off. The remaining solid weighed $$160$$ g. From these data, the percent of water by weight in the original sample can be correctly calculated as :
  • $$\cfrac { 160 }{ 340 } \times 100$$ %
  • $$\cfrac { 90 }{ 340 } \times 100$$ %
  • $$\cfrac { 160 }{ 250 } \times 100$$ %
  • $$\cfrac { 90 }{ 250 } \times 100$$ %
  • $$\cfrac { 90 }{ 160 } \times 100$$ %
14 g of nitrogen contains $$3.01 \times 10^{23}$$ nitrogen molecules.
  • True
  • False
If 'M' is the molecular weight of a gas, what volume in $$l$$ at STP would be occupied by M/4 g of that gas?
  • 11.2
  • 2.24
  • 5.6
  • 22.4
What is the percent composition by mass of aluminium in a compound of aluminium and oxygen if the mole ratio of $$Al : O$$ is $$2:3$$?
  • $$37$$% $$Al$$
  • $$47$$% $$Al$$
  • $$53$$% $$Al$$
  • $$63$$% $$Al$$
  • $$74$$% $$Al$$
Two gases A and B are taken in same volume containers under similar conditions of temperature and pressure. In container A, there are '2N' molecules of gas A. How many number molecules does container B have? 
  • 2N
  • 4N
  • N
  • 8N
What is the molar mass of ammonium carbonate $${({NH}_{4})}_{2}{CO}_{3}$$?
  • $$48\ g/mol$$
  • $$96\ g/mol$$
  • $$82\ g/mol$$
  • $$78\ g/mol$$
  • $$192\ g/mol$$
64 g of sulphur dioxide occupies $$22.4\ L$$ volume at STP.
  • True
  • False
Hydrogen, oxygen and carbon dioxide are taken in containers of $$2 l$$ volume each. Compare the ratio of the number of molecules of the three gases respectively, under same conditions of temperature and pressure.
  • 1:8:22
  • 1:1:1
  • 1:16:44
  • 1:8:44
$$2K(s)+2{H}_{2}O(l)\rightarrow 2KOH(aq)+{H}_{2}(g)$$
If $$3.0$$ moles of potassium react with excess water, what volume of hydrogen gas will be produced?
  • $$1.5L$$
  • $$22.4L$$
  • $$67.2L$$
  • $$33.6L$$
What is the atomic mass of sodium?
  • $$22\ g/mol$$
  • $$23\ g/mol$$
  • $$11\ g/mol$$
  • $$20\ g/mol$$
What is the relative atomic mass of cadmium?
  • 112.411 amu
  • 20.00 amu
  • 21.00 amu
  • 20.43 amu
The father of modern chemistry is:
  • Priestley
  • Lavoisier
  • Dalton
  • Mendeleev
A $$5.0g$$ sample of copper(II) oxide containing an inert contaminant is analyzed and found to contain $$3.0g\ Cu$$. Using molar masses of $$64g/mol$$ for copper, and $$16g/mol$$ for oxygen, determine the percent purity of the copper(II) oxide sample.
  • $$80$$%
  • $$75$$%
  • $$60$$%
  • $$50$$%
Use the figure below to answer the question that follows.
Which of the four molecules has the highest percentage of nitrogen, by mass?
526409.jpg
  • I
  • II
  • III
  • IV
A student would like to use gravimetric analysis to determine the percent by mass of magnesium chloride in a contaminated mixture containing magnesium chloride.
Which of the following compounds would be the BEST substance to react the contaminated mixture with to determine the mass percent?
  • silver nitrate.
  • Potassium chloride.
  • Sodium acetate.
  • Lithium sulfate.
How many grams are there in a $$7.0$$ mole sample of sodium hydroxide?
  • $$40.0g$$
  • $$140.0\ g$$
  • $$280.0\ g$$
  • $$340.0\ g$$
  • $$420.0\ g$$
A hydrate sample of magnesium chloride is analyzed and found to contain $$53.18$$% water.
How many water molecules are found in the formula for this hydrate?
  • Two
  • Four
  • Six
  • Eight
What would be the approximate weight of $$1.204\times 10^{24}$$ bromine atoms?
  • 80 grams
  • 120 grams
  • 160 grams
  • 180 grams
  • 200 grams
Which pair of substances share the same mass percent of each element?
  • $$NaOCl$$ and $$OCl^{-}$$
  • $$CO$$ and $$CO_{2}$$
  • $$C_{6}H_{12}O_{6}$$ and $$C_{3}H_{6}O_{3}$$
  • None of these pairs of substances share the same mass percent.
A mixture contains $$5.0\ g$$ of compound $$X$$ and $$20.0\ g$$ of compound $$Y$$.What is the percent by mass of compound $$X$$?
  • $$75$$
  • $$25$$
  • $$80$$
  • $$20$$
How many atoms of hydrogen are present in $$7.8\ g$$ of $$Al{(OH)}_{3}$$?
  • $$6.0\times {10}^{22}$$
  • $$1.8\times {10}^{23}$$
  • $$1.7\times {10}^{23}$$
  • $$5.1\times {10}^{22}$$
What could be better than a dozen $$(12)$$ donuts? How about a baker's dozen $$(13)$$ of donuts? Another large unit of measurement is known as Avogadro's number $$(6.022\times 10^{23})$$.
What is TRUE about Avogadro's number?
  • Avogadro's number is the number of particles in one mole of any element.
  • The molar mass of a substance will contain $$6.022\times 10^{23}$$ molecules.
  • There are $$6.022\times 10^{23}g$$ of carbon in $$12$$ mol of $$C - 12$$.
  • $$6.022\times 10^{23}$$ atoms of any element will have the exact same mass regardless of the identity of the element.
What is the correct unit for the following solution?

$$10.5\ g$$ of $${C}_{7}{H}_{8}O$$ in $$100\ g$$ of water as a topical treatment for poison ivy.
  • $$w/w$$
  • $$m$$
  • $$M$$
  • $$v/v$$
What is the mass of $$6.022\times { 10 }^{ 23 }$$ formula units of $${({NH}_{4})}_{2}{SO}_{4}$$?
  • $$234.11\ g$$
  • $$132.11\ g$$
  • $$210.29\ g$$
  • $$342.14\ g$$
A compound contains 38.8% C, 16.0% H and 45.2% N. The formula of the compound would be
  • $$\mathrm { CH } _ { 3 } \mathrm { NH } _ { 2 }$$
  • $$\mathrm { CH } _ { 3 } \mathrm { CN }$$
  • $$\mathrm { C } _ { 2 } \mathrm { H } _ { 5 } \mathrm { CN }$$
  • $$\mathrm { CH } _ { 2 } ( \mathrm { NH } ) _ { 2 }$$
If you are given Avogadro's number of atoms of a gas $$X$$. If half of the atoms are converted into $${X}_{(g)}$$ by energy $$\Delta H$$. The IE of $$X$$ is
  • $$\cfrac{2\Delta H}{{N}_{A}}$$
  • $$\cfrac{2{N}_{A}}{\Delta H}$$
  • $$\cfrac{\Delta H}{2{N}_{A}}$$
  • $$\cfrac{{N}_{A}}{\Delta H}$$
The image below represents the formation of potassium bromide, $$KBr$$. Which law is represented by this reaction?
528586.jpg
  • Law of Conservation of Mass
  • Law of Multiple Proportions
  • Law of Definite Proportions
  • Law of Stoichiometry
Using the mass spectrum provided below:
Determine the relative atomic mass and identify the element.
527440.jpg
  • $$Be, 9.0122\ amu$$
  • $$B, 10.199\ amu$$
  • $$C, 12.011\ amu$$
  • $$N, 14.007$$
The atomic mass of copper is $$64\ amu$$, while the atomic mass of oxygen is $$16\ amu$$.
Let $$= copper$$ and $$= oxygen$$.
Which of the following would represent a compound that was $$50$$% copper, by mass?
528602_d13382d2436d4c97a96507efc4c0ceef.png
If a copper-containing compound contains $$4.999$$% $$Cu$$ by mass and there are $$2$$ copper atoms per formula unit, what is the molar mass of the compound?
  • $$2547\ g/mol$$
  • $$47.50\ g/mol$$
  • $$31.75\ g/mol$$
  • $$1274\ g/mol$$
How many molecules of methane are present in a sample that contains $$1.0\times { 10 }^{ 10 }$$ moles of methane?
  • $$6.0\times { 10 }^{ 23 }$$
  • $$1.0\times { 10 }^{ 33 }$$
  • $$6.0\times { 10 }^{ 33 }$$
  • $$6.0\times { 10 }^{ 24 }$$
How many grams of $$CaWO_4$$ would contain the same mass of tungsten that is present in 569g of $$FeWO_4$ $? (W=184)
  • $$298$$ g
  • $$540$$ g
  • $$487$$ g
  • $$474$$ g
What is the percent $$X$$ by mass for compound $$XY_{2}$$ if compound $$XY$$ is $$74$$% $$X$$ by mass?
  • $$25$$%
  • $$40$$%
  • $$60$$%
  • $$75$$%
Equal masses of oxygen, hydrogen, and methane are taken in a container in identical condition. Find the ratio of volumes of the gases.
  • 1: 32 :2
  • 1 : 16: 2
  • 1 : 1: 1
  • 1: 16 :1
0:0:1


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