Maharashtra Board Solutions for Chapter: Introduction to Analytical Chemistry, Exercise 1: Exercises

Perform the following operation :
$3.971\times {10}^7 + 1.98\times {10}^4$

Perform the following operation :
$1.05\times {10}^{-4} - 9.7\times {10}^{-5}$

Perform the following operation :
$4.11\times {10}^{-3} + 8.1\times {10}^{-4}$

Perform the following operation :
$2.12\times {10}^6 - 3.5 \times {10}^5$

A $1.000 \mathrm{mL}$ sample of acetone, a common solvent used as a paint remover, was placed in a small bottle whose mass was known to be $38.0015 \mathrm{g}$. The following values were obtained when the acetone - filled bottle was weighed: $38.7798 \mathrm{g}, 38.7795 \mathrm{g} \mathrm{and} 38.7801 \mathrm{g}.$ How would you characterize the precision and accuracy of these measurements if the actual mass of the acetone was $0.7791 \mathrm{g}?$

Your laboratory partner was given the task of measuring the length of a box (approx $5$ inches) as accurately as possible, using a meter stick graduated in millimeters. He supplied you with the following measurements: $12.65 \mathrm{cm}, 12.6 \mathrm{cm}, 12.65 \mathrm{cm}, 12.655 \mathrm{cm}, 126.55 \mathrm{mm}, 12 \mathrm{cm}.$

• State which of the measurements you would accept, giving the reason.
• Give your reason for rejecting each of the others.

What weight of calcium oxide will be formed on heating $19.3 \mathrm{g}$ of calcium carbonate? $(\mathrm{At}. \mathrm{wt}. : \mathrm{Ca} = 40; \mathrm{C} = 12; \mathrm{O} = 16)$

The hourly energy requirements of an astronaut can be satisfied by the energy released when $34$ grams of sucrose is “burnt” in his body. How many grams of oxygen would be needed to be carried in space capsule to meet his requirement for one day?