Question 36 4.54 × 10 -4 0.454 0.0654 0.0342 3.42 2 points Question 37 A 1.36-g

Question

Question 36

4.54 × 10-4

0.454

0.0654

0.0342

3.42

2 points   

Question 37

A 1.36-g sample of magnesium nitrate, Mg(NO3)2, contains ________ mol of this compound.

2.32

1.65

0.111

0.0182

0.00917

2 points   

Question 38

How many moles of lithium phosphate (Li3PO4) are contained in 66.6 g of lithium phosphate?

0.575

7710

1.11 × 10-22

4.01 × 1025

116

2 points   

Question 39

A solution is prepared by dissolving 27.7 g of CaCl2 in 375 g of water. The density of the resulting solution is 1.05 g/mL. The concentration of CaCl2 is ________% by mass.

6.88

7.22

0.0722

0.0688

6.24

2 points   

Question 40

What is the formula for phosphoric acid?

H3PO4

H2PO4

H4PO4

H3PO3

None of these

2 points   

Question 41

Calculate the molarity of phosphoric acid (H3PO4) in a 22.1% (by mass) aqueous solution.

0.0522 m

0.0992 m

0.0248 m

0.0496 m

The density of the solution is needed to solve the problem.

2 points   

Question 42

The number 0.0101 has ________ significant figures.

2

3

5

4

6

2 points   

Question 43

Calculate the mole fraction of phosphoric acid (H3PO4) in a 38.5% (by mass) aqueous solution.

0.103

0.115

0.206

0.0516

The density of the solution is needed to solve the problem.

2 points   

Question 44

0.146

0.563

3.55

7.10

1.78

2 points   

Question 45

A 30.5 gram sample of glucose (C6H12O6) contains ________ atoms of carbon.

9.17 × 1024

6.12 × 1023

1.70 × 1022

1.69 × 10-24

1.02

2 points   

Question 46

Which one of the following exhibits dipole-dipole attraction between molecules?

NH3

CF4

C10H22

O2

SF6

2 points   

Question 47

What is the mass % of carbon in dimethylsulfoxide (C2H6SO) rounded to three significant figures?

25.4

28.6

30.7

7.74

78.1

2 points   

Question 48

With what compound will NH3 experience only ion-dipole intermolecular forces?

LiCl

SiH4

CH3I

C3H7OH

OCl2

2 points   

Question 49

There are ________ atoms of oxygen in 300 molecules of CH3CO2H.

300

600

150

3.6 × 1026

1.0 × 10-22

2 points   

Question 50

The symbol for the element neon is ________.

Rb

Si

Mg

Mn

Ne

4.54 × 10-4

0.454

0.0654

0.0342

3.42

Explanation / Answer

Answer:

37.

Gram Molecular weight of Mg(NO3)2 = 148 grams

Number of moles = Given weight/Molecular weight

= 36/148

= 0.243

38.

Molecular formula of Lithium phosphate is Li3(PO4).

Gram Molecular weight of Lithium phosphate is - 116 grams

Number of moles of lithium phosphate = given weight/ molecular weight

= 66.6/116 = 0.015

40.

Chemical formula of Phosphoric acid is H3PO4.

42.

The number of significant figures in 0.0101 are 4.

44.

Mg + O2 2MgO

1 mole of Mg reacts with 1 mole of Oxygen to form 2 moles of MgO.

3.55 moles of Mg will burn with 3.55 moles of O2 to form (2*3.55) moles of MgO.

45.

Gram Molecular weight of Glucose 180 grams

Thus 180 grams of Glucose contains 6.023*1023 number of Carbon atoms.

30.5 grams of Glucose will contain = (30.5*6.023*1023)/180

= 1.02*1023 number of Carbon atoms

46.

In Ammonia there exists dipole - dipole interactions.

48.

With LiCl the Ammonia form ion - dipole intermolecular forces.

50. Ne is th symbol for Neon.

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