Question

State the mass law(s) demonstrated by the following experimental results, and explain your reasoning:

Experiment 1: A student heats 1.00 g of a blue compound and obtains 0.64 g of a white compound and 0.36 g of a colour less gas.

Experiment 2: A second student heats 3.25 g of the same blue compound and obtains 2.08 g of a white compound and 1.17 g of a colour less gas.

Short answer

Individually both experiment 1 and experiment 2 demonstrate the “Law of Conservation of Mass” while collectively they demonstrate the “Law of Definite Composition.”

Step-by-step solution

Explanation of Experiment 1

Experiment 1 is given as:

$$\begin{gathered} \mathbf{Reactant}\mathbf{}\mathbf{(}\mathbf{blue}\mathbf{}\mathbf{compound}\mathbf{)}\mathbf{=}\mathbf{White}\mathbf{}\mathbf{compound}\mathbf{+}\mathbf{col}\mathbf{}\mathbf{or}\mathbf{}\mathbf{less}\mathbf{}\mathbf{gas} \\ \mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{1}\mathbf{g}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{0}\mathbf{.}\mathbf{64}\mathbf{}\mathbf{g}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{0}\mathbf{.}\mathbf{36}\mathbf{}\mathbf{g} \end{gathered}$$From the equation, we can say that,

$\mathbf{Mass}\mathbf{}\mathbf{of}\mathbf{}\mathbf{reactant}\mathbf{}\mathbf{\left(}\mathbf{1}\mathbf{g}\mathbf{\right)}\mathbf{=}\mathbf{Mass}\mathbf{}\mathbf{of}\mathbf{}\mathbf{products}\mathbf{}\mathbf{(}\mathbf{0}\mathbf{.}\mathbf{64}\mathbf{+}\mathbf{0}\mathbf{.}\mathbf{36}\mathbf{=}\mathbf{1}\mathbf{g}\mathbf{)}$

As remains constant before and after the reaction hence it demonstrates the “law of Conservation of Mass.”

Explanation of Experiment 2

Experiment 2 is given as:

$$\begin{gathered} \mathbf{Reactant}\mathbf{}\mathbf{(}\mathbf{blue}\mathbf{}\mathbf{compound}\mathbf{)}\mathbf{=}\mathbf{White}\mathbf{}\mathbf{compound}\mathbf{+}\mathbf{col}\mathbf{}\mathbf{or}\mathbf{}\mathbf{less}\mathbf{}\mathbf{gas} \\ \mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{3}\mathbf{.}\mathbf{25}\mathbf{g}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{2}\mathbf{.}\mathbf{08}\mathbf{}\mathbf{g}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{1}\mathbf{.}\mathbf{17}\mathbf{g} \end{gathered}$$

From the equation, we can say that,

$\mathbf{Mass}\mathbf{}\mathbf{of}\mathbf{}\mathbf{reactant}\mathbf{}\mathbf{(}\mathbf{3}\mathbf{.}\mathbf{25}\mathbf{}\mathbf{g}\mathbf{)}\mathbf{=}\mathbf{Mass}\mathbf{}\mathbf{of}\mathbf{}\mathbf{products}\mathbf{(}\mathbf{2}\mathbf{.}\mathbf{08}\mathbf{+}\mathbf{1}\mathbf{.}\mathbf{17}\mathbf{=}\mathbf{3}\mathbf{.}\mathbf{25}\mathbf{}\mathbf{g}\mathbf{)}$

As remains constant before and after the reaction hence it demonstrates the “law of Conservation of Mass.”

Both Experiments

Both experiments collectively demonstrate the Law of Definite Composition. As the relative amounts of each product are the same in both experiments.

$$\begin{gathered} \mathbf{Ratio}\mathbf{}\mathbf{of}\mathbf{}\mathbf{products}\mathbf{}\mathbf{in}\mathbf{}\mathbf{experminet}\mathbf{}\mathbf{1}\mathbf{=}\frac{\mathbf{0}\mathbf{.}\mathbf{64}}{\mathbf{0}\mathbf{.}\mathbf{36}}\mathbf{=}\mathbf{1}\mathbf{.}\mathbf{78}\mathbf{:}\mathbf{1} \\ \mathbf{Ratio}\mathbf{}\mathbf{of}\mathbf{}\mathbf{products}\mathbf{}\mathbf{in}\mathbf{}\mathbf{experminet}\mathbf{}\mathbf{2}\mathbf{=}\frac{\mathbf{2}\mathbf{.}\mathbf{08}}{\mathbf{1}\mathbf{.}\mathbf{17}}\mathbf{=}\mathbf{1}\mathbf{.}\mathbf{78}\mathbf{:}\mathbf{1} \end{gathered}$$