Which of the following statements describe physical properties and which describe chemical properties? (a) Iron has a tendency t

Response:

22.9 moles (Option 5)

Clarification:

A substance being 35.7% carbon by mass signifies that in every 100 g of the substance, there is 35.7 g of carbon.

Using a rule of three, we get:

100 g of substance ___ has __ 35.7 g of C

769 g of substance ___ has ___ ( 769.35.7) / 100 = 274.5 g of C

1 mol of C = 12 g/m

Mass / Molar mass = Moles

274.5 g / 12 g/m = 22.9 moles

Response:

The result is a pH of 7. I’m uncertain about the mechanics of Hydrochloric acid reactions

Explanation:

A mixture refers to a substance that contains two or more different kinds of substances that are combined physically.

For instance, air is a mixture that contains oxygen, nitrogen, and other gases.

A heterogeneous mixture is characterized by uneven distribution of solute particles in the solvent.

For example, sand suspended in water is a heterogeneous mixture.

Conversely, a homogeneous mixture is one where the solute particles are uniformly distributed in a solvent.

A homogeneous mixture appears as a clear solution.

For instance, when salt dissolves in water, it forms a homogeneous mixture.

A solution is defined as a mixture of two or more substances combined together.

A compound consists of two or more different elements chemically bonded together in a specific mass ratio.

An element is the simplest form of a substance that comprises only one type of atom.

For example, a piece of sodium is composed solely of sodium atoms.

Conversely, a pure substance refers to a material consisting of just one type of molecule or atom.

For example, , etc are considered pure substances.

Thus, it can be concluded that the air sample can be described using the terms:

• pure chemical substance.

• heterogeneous mixture.

• mixture.

Response:

a. To purify a gypsum sample, you will need the following equipment: Bunsen burner, beaker, filter funnel, stirring rod, and filter paper.

b. Gypsum, a sulfate mineral consisting of calcium sulfate dihydrate, can be purified by following these steps:

1. Add water to the gypsum in a beaker.

2. Stir the mixture thoroughly with the stirring rod.

3. Use the filter paper and filter funnel to remove excess solids from the mixture.

4. Heat the filtered mixture on the Bunsen burner to evaporate the remaining water.

5. After cooling, filter again through the filter paper to obtain pure gypsum.

Answer:

2(CH3)2N2H2 + 3N2O4 → 4N2 + 4H2O + 4CO2 + heat

Explanation:

• To balance chemical equations, coefficients are assigned to both reactants and products.
• This yields an equal count of atoms of each element on both sides of the equation.
• Balancing chemical equations ensures compliance with the law of conservation of mass.
• According to this law, the mass of reactants must equal the mass of products, achievable through balancing the equation.
• The application of coefficients 2, 3, 4, 4, 4 allows for an equal balance in the equation.
• Consequently, the balanced equation can be written as:

       2(CH3)2N2H2 + 3N2O4 → 4N2 + 4H2O + 4CO2 + heat