In English with meaningful answers and calculations

The atomic number of X is 12, and its mass number is 24. This identifies element X as Magnesium (Mg).
Magnesium is an alkaline earth metal. It is a solid at room temperature and is known to burn in air, producing a bright white light.

b) Determine the formula of the oxide X.

$$\text{Mass of oxygen} = \text{Mass of oxide} - \text{Mass of X}$$ $$\text{Mass of oxygen} = 0.5 \text{ g} - 0.3 \text{ g} = 0.2 \text{ g}$$

The molar mass of Mg is $24 \text{ g/mol}$, and the molar mass of O is $16 \text{ g/mol}$.

$$\text{Moles of Mg} = \frac{0.3 \text{ g}}{24 \text{ g/mol}} = 0.0125 \text{ mol}$$ $$\text{Moles of O} = \frac{0.2 \text{ g}}{16 \text{ g/mol}} = 0.0125 \text{ mol}$$

$$\text{Ratio of moles Mg:O} = 0.0125 : 0.0125 = 1:1$$

The formula of the oxide is $\boxed{\text{MgO}}$.

c) Know the environmental consequences of the element.
The environmental consequences of magnesium primarily stem from its extraction and processing. Mining magnesium can lead to habitat destruction, soil erosion, and water pollution. Magnesium oxide (MgO), while generally stable, is a basic oxide and could affect the pH balance of local environments if released in large quantities.

Item two:

a) Assess the product formed.
The product formed from the complete combustion of charcoal (carbon) in excess oxygen is carbon dioxide ($CO_2$). It is a gaseous compound and is classified as a greenhouse gas.

b) Advise the friend on the appropriateness of the product formed.
The production of carbon dioxide ($CO_2$) during cooking, especially indoors, is not appropriate without proper ventilation. $CO_2$ can accumulate in enclosed spaces, displacing oxygen and leading to suffocation. Environmentally, $CO_2$ is a major greenhouse gas that contributes to global warming.

c) Calculate the volume of the gas produced every busy evening.

The molar mass of carbon (C) is $12 \text{ g/mol}$.

$$\text{Moles of C} = \frac{\text{Mass of C}}{\text{Molar mass of C}} = \frac{80.5 \text{ g}}{12 \text{ g/mol}} \approx 6.7083 \text{ mol}$$

The balanced equation is $C_{(s)} + O_{2(g)} \rightarrow CO_{2(g)}$.
From the equation, 1 mole of C produces 1 mole of $CO_2$.

$$\text{Moles of } CO_2 = \text{Moles of C} \approx 6.7083 \text{ mol}$$

At RTP, 1 mole of any gas occupies $24 \text{ dm}^3$.

$$\text{Volume of } CO_2 = \text{Moles of } CO_2 \times 24 \text{ dm}^3/\text{mol}$$ $$\text{Volume of } CO_2 = 6.7083 \text{ mol} \times 24 \text{ dm}^3/\text{mol} \approx 160.9992 \text{ dm}^3$$

The volume of carbon dioxide gas produced is approximately $\boxed{161.0 \text{ dm}^3}$.

d) Help the friend understand the impact of the product in the environment.
Carbon dioxide ($CO_2$) is a primary greenhouse gas. Its accumulation in the atmosphere traps heat, leading to global warming and climate change. This can result in rising sea levels, extreme weather events, and disruptions to ecosystems.