Chemistry 10 Final Exam Review - Free Response

Explanation
The correct answer is 2S + Cl2 = S2Cl2. This equation represents the balanced chemical reaction between sulfur and chlorine to form disulfur dichloride. The coefficients in front of each compound indicate the number of molecules or moles involved in the reaction, ensuring that the equation follows the law of conservation of mass.

Explanation
Combustion yields H2O + CO2, CO2 + H2O, CO2 + H2O, CO2 + H2O, C02 + H20, C02 + H20, H20 + C02, and H20 + C02.

Explanation
The answer options provided all express the same value, which is 1.50x10^2, in different formats. This value represents the number of atoms of boron. The scientific notation format, 1.50x10^2, indicates that there are 1.50 multiplied by 10 raised to the power of 2 atoms of boron. This is equivalent to 150 atoms of boron. The "rp" in the answer options likely stands for "representative particles," which includes both atoms and molecules. Therefore, all the answer options correctly state that there are 1.50x10^2 atoms of boron.

Explanation
The given number, 4898000, needs to be written in scientific notation with three significant figures. To do this, we move the decimal point to the left until there is only one non-zero digit to the left of the decimal point. In this case, we move the decimal point four places to the left, resulting in 4.898000. To maintain three significant figures, we round this number to 4.90. Finally, we express this number in scientific notation by multiplying it by 10 raised to the power of the number of places the decimal point was moved. Since we moved the decimal point four places to the left, the exponent is 6. Therefore, the number in scientific notation is 4.90 x 10^6.

Explanation
The mole-to-mole ratio for the given equation is 1:1:1:3. This means that for every 1 mole of SeCl6, 1 mole of O2, 1 mole of SeO2, and 3 moles of Cl2 are produced or consumed in the reaction.

Explanation
The mole-to-mole ratio of the given equation is 2:3:2. This means that for every 2 moles of P4, 3 moles of O2 are required and 2 moles of P2O3 are produced. This ratio is determined by the coefficients of the balanced equation, which indicate the relative number of moles of each substance involved in the reaction.

Explanation
The given answer provides the mole-to-mole ratio of the reactants and products, which is 1:3:3:1. This means that for every 1 mole of H3PO4, there are 3 moles of KOH, 3 moles of HOH (water), and 1 mole of K3PO4 produced. The answer also states that 133 grams of HOH and 523 grams of K3PO4 are produced as a result of the reaction. Additionally, the answer proves the law of conservation of mass (LOCOM) by showing that the sum of the reactants (427 grams of H3PO4 + 415 grams of KOH) is equal to the sum of the products (657 grams).

Explanation
Zinc is more reactive than iron because it has a lower ionization energy and a higher tendency to lose electrons. This means that zinc is more likely to undergo chemical reactions and form compounds compared to iron. Additionally, zinc has a higher electronegativity, which means it can attract electrons more strongly and form more stable compounds. Therefore, zinc is considered to be more reactive than iron.

Explanation
The number 0.000374 has three significant figures. The zeros before the 3 and after the 7 are not significant because they are leading and trailing zeros. The significant figures in this number are 3, 7, and 4.

Explanation
The number 298001000 has six significant figures. Significant figures are the digits in a number that carry meaning in terms of its precision. In this case, all the digits from 2 to the last 0 are significant, giving a total of six significant figures.