Chapter 5, Problem 9STP

(a)

Interpretation Introduction

Interpretation : The volume of water in each beaker with the proper number of significant figures needs to be determined.

Concept Introduction : A number can be changed to given significant figure either by round off or by addition of zero. The rules for significant figures are:

1. Non-zero digits are always significant.
2. Any zeros between two significant digits are always significant.
3. A final zero in the decimal portion is also significant.

Answer to Problem 9STP

Beaker I = 27.0 mL

Beaker II = 20.0 mL

Beaker III = 26.4 mL

Explanation of Solution

Each beaker has its marking of volume. The beaker I and II have the difference of 1 unit of volume whereas beaker III has more precise value of volume as it has difference of 0.1 unit of volume. Thus, the volume of water in each beaker is:

• Beaker I = 27.0 mL
• Beaker II = 20.0 mL
• Beaker III = 26.4 mL

(b)

Interpretation Introduction

Interpretation : The digits in each measurement from part A needs to be identified as certain and uncertain.

  

Concept Introduction : A number can be changed to given significant figure either by round off or by addition of zero. The rules for significant figures are:

1. Non-zero digits are always significant.
2. Any zeros between two significant digits are always significant.
3. A final zero in the decimal portion is also significant.

Answer to Problem 9STP

Beaker I = Uncertain

Beaker II = Uncertain

Beaker III = Certain

Explanation of Solution

The beaker I and II have the difference of 1 unit of volume whereas beaker III has more precise value of volume as it has difference of 0.1 unit of volume. Since beaker III has more precise volume so it has certain value of volume whereas beaker I and II has uncertain value of volume.

(c)

Interpretation Introduction

Interpretation : The total volume of water if all the three beakers pour in one container needs to be determined with correct number of significant figures.

  

Concept Introduction : A number can be changed to given significant figure either by round off or by addition of zero. The rules for significant figures are:

1. Non-zero digits are always significant.
2. Any zeros between two significant digits are always significant.
3. A final zero in the decimal portion is also significant.

Answer to Problem 9STP

The total volume must be 27.0 +20.0 + 26.4 = 73.4 mL

Explanation of Solution

The beaker I and II have the difference of 1 unit of volume whereas beaker III has more precise value of volume as it has difference of 0.1 unit of volume. The volume of water in each beaker is:

• Beaker I = 27.0 mL
• Beaker II = 20.0 mL
• Beaker III = 26.4 mL

Thus, the total volume must be 27.0 +20.0 + 26.4 = 73.4 mL