Calculate the following quantities: (b) moles of Zn(NO₃)₂ in 143.50 g of this substance

Verified step by step guidance

1. First, determine the molar mass of Zn(NO3)2. To do this, add the atomic masses of all the atoms in the formula: Zn, N, and O. Use the periodic table to find these values: Zn = 65.38 g/mol, N = 14.01 g/mol, and O = 16.00 g/mol.
2. Calculate the molar mass of Zn(NO3)2 by adding the atomic masses: 1 Zn atom, 2 N atoms, and 6 O atoms. The formula is: Molar mass = (1 * 65.38) + (2 * 14.01) + (6 * 16.00).
3. Once you have the molar mass, use it to convert grams to moles. The formula to use is: moles = mass (g) / molar mass (g/mol).
4. Substitute the given mass of Zn(NO3)2, which is 143.50 g, and the calculated molar mass into the formula to find the number of moles.
5. Perform the division to find the moles of Zn(NO3)2 in 143.50 g. This will give you the quantity in moles.

Key Concepts

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all the atoms in a chemical formula. For zinc nitrate, Zn(NO3)2, the molar mass can be determined by adding the atomic mass of zinc (Zn) and twice the sum of the atomic masses of nitrogen (N) and three times the atomic mass of oxygen (O).

Moles

A mole is a unit in chemistry that represents 6.022 x 10^23 entities, such as atoms or molecules. It provides a bridge between the atomic scale and macroscopic quantities, allowing chemists to count particles by weighing them. The number of moles of a substance can be calculated using the formula: moles = mass (g) / molar mass (g/mol).

Stoichiometry

Stoichiometry is the area of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It allows chemists to predict the amounts of substances consumed and produced in a reaction based on balanced chemical equations. In this context, stoichiometry is essential for converting mass to moles, which is crucial for understanding the composition of compounds like Zn(NO3)2.