Chemistry Quiz: Explore The Wonders Of Chemistry

In a molecule of water (H2O), there are 2 hydrogen atoms and 1 oxygen atom. The ratio of hydrogen to oxygen is therefore 2:1.

The balanced equation for the combustion of ethane (C2H6) is 2C2H6 + 7O2 → 4CO2 + 6H2O. From the equation, 2 moles of C2H6 produce 4 moles of CO2. Therefore, if 5 moles of C2H6 are combusted, the amount of CO2 produced will be (5 moles C2H6 * 4 moles CO2 / 2 moles C2H6) = 10 moles of CO2.

1 mole of any substance contains Avogadro's number of molecules, which is 6.022 x 10^23. For 1 mole of CO2 (carbon dioxide), each molecule contains 3 atoms (1 carbon and 2 oxygen atoms). Therefore, 1 mole of CO2 contains 3 times Avogadro's number of atoms, which is more than the number of atoms in 1 mole of H2 (2 atoms per molecule), O2 (2 atoms per molecule), or N2 (2 atoms per molecule).

In a molecule of methane (CH4), there is 1 carbon atom and 4 hydrogen atoms. Therefore, the molar ratio of carbon to hydrogen is 1:4.

Hydrogen peroxide (H2O2) has 2 oxygen atoms per molecule. Comparatively, water (H2O) has 1 oxygen atom per molecule, carbon dioxide (CO2) has 2 oxygen atoms per molecule, and oxygen gas (O2) has 2 oxygen atoms per molecule. However, because each molecule of H2O2 contains 2 oxygen atoms and also has an additional 2 hydrogen atoms, it has the highest number of oxygen atoms per mole among the options given.

The balanced chemical equation for the reaction between hydrogen and oxygen to form water is 2H2 + O2 → 2H2O. This means that 2 moles of hydrogen gas (H2) react with 1 mole of oxygen gas (O2) to produce 2 moles of water (H2O). Since the question states that 2 moles of H2 react with 1 mole of O2, the product will be 2 moles of H2O.

Potassium (K) is more reactive than Sodium (Na) because it is lower in the alkali metals group in the periodic table. Reactivity in alkali metals increases as you move down the group, so potassium, being below sodium, is more reactive.

The balanced equation for the reaction between sodium (Na) and chlorine gas (Cl2) to form sodium chloride (NaCl) is 2Na + Cl2 → 2NaCl. This indicates that 2 moles of Na react with 1 mole of Cl2 to produce 2 moles of NaCl. Since the question states that 2 moles of Na react with 2 moles of Cl2, the product will still be 2 moles of NaCl, with excess Cl2 left unreacted.

Calcium (Ca) is more reactive than Magnesium (Mg) because it is located below magnesium in the alkaline earth metals group in the periodic table. Reactivity in alkaline earth metals increases as you move down the group, so calcium is more reactive than magnesium.

The balanced chemical equation for the formation of ammonia (NH3) is N2 + 3H2 → 2NH3. This means that 1 mole of nitrogen gas (N2) reacts with 3 moles of hydrogen gas (H2) to produce 2 moles of ammonia (NH3). Therefore, 3 moles of H2 are required to react with 1 mole of N2.