Chapter 3, Problem 3.20P

(a)

Interpretation Introduction

Interpretation:

The formula mass and its uncertainty for ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ has to be found out.

Concept Introduction:

Uncertainty:

Uncertainty means state of not certain in predicting a value.  In a measured value, the last digit will have associated uncertainty. Uncertainty has two values, absolute uncertainty and relative uncertainty.

Absolute uncertainty:

Expressed the marginal value associated with a measurement

Relative uncertainty:

Compares the size of absolute uncertainty with the size of its associated measurement

$\text{Relative uncertainty = }\frac{\text{absolute uncertainty}}{\text{magnitude of measurement}}$

To Find: The formula mass and its uncertainty for ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$

(b)

Interpretation Introduction

Interpretation:

The molarity of $\text{HCl}$ and its absolute uncertainty has to be found out.

Concept Introduction:

Uncertainty:

Uncertainty means state of not certain in predicting a value.  In a measured value, the last digit will have associated uncertainty. Uncertainty has two values, absolute uncertainty and relative uncertainty.

Absolute uncertainty:

Expressed the marginal value associated with a measurement

Relative uncertainty:

Compares the size of absolute uncertainty with the size of its associated measurement

$\text{Relative uncertainty = }\frac{\text{absolute uncertainty}}{\text{magnitude of measurement}}$

Molarity:

$\text{Molarity = }\frac{\text{No}\text{. of moles}}{\text{Liter}}$

To Find: The molarity of $\text{HCl}$ and its absolute uncertainty

(c)

Interpretation Introduction

Interpretation:

When the purity of ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ is considered as $(100.00\pm 0.05)\%$, the molarity of $\text{HCl}$ and its absolute uncertainty has to be recalculated from part (b).

Concept Introduction:

Uncertainty:

Uncertainty means state of not certain in predicting a value.  In a measured value, the last digit will have associated uncertainty. Uncertainty has two values, absolute uncertainty and relative uncertainty.

Absolute uncertainty:

Expressed the marginal value associated with a measurement

Relative uncertainty:

Compares the size of absolute uncertainty with the size of its associated measurement

$\text{Relative uncertainty = }\frac{\text{absolute uncertainty}}{\text{magnitude of measurement}}$

Molarity:

$\text{Molarity = }\frac{\text{No}\text{. of moles}}{\text{Liter}}$

To Calculate: The molarity of $\text{HCl}$ and its absolute uncertainty when the purity of ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ is considered as $(100.00\pm 0.05)\%$.