THE CORE PRINCIPLES OF CHEMISTRY_2

What is the formula for calculating parts per million (ppm) in chemistry?

• A) ppm = mass of component x mass of solution

• B) ppm = mass of solution / mass of component

• C) ppm = mass of component / mass of solution x 10^6

• D) ppm = mass of solution / mass of component x 10^6

To calculate the concentration of organophosphate pollution in parts per million (ppm), what is the formula or method to use when given 2 grams of organophosphate pollution in 1.5 million grams of solution?

• A) Divide the mass of the pollution by the total mass of the solution and multiply by 1,000,000.

• B) Divide the mass of the pollution by the total mass of the solution and multiply by 100,000.

• C) Multiply the mass of the pollution by 1,000,000 and then divide by the total mass of the solution.

• D) Multiply the mass of the pollution by 100,000 and then divide by the total mass of the solution.

If there are 2 grams of organophosphate pollution in 1.5 million grams of solution, what is the concentration of organophosphate pollution in parts per million (ppm)?

• A) 0.00133 ppm

• B) 0.02 ppm

• C) 1.5 ppm

• D) 1333.33 ppm

You have a blood sample with the following concentrations of various species: Creatinine (a waste product of muscle metabolism) 60 - 120 mmol dm^(-3), Urea (a waste product of protein metabolism) 3.5 – 6.5 mmol dm^(-3), Na+ (sodium ions) 135 – 145 mmol dm^(-3), and K+ (potassium ions) 3.5 - 5.0 mmol dm^(-3). To calculate the minimum mass of sodium ions in the blood of an average person, which formula should you use based on the given data?

• A) Mass = Concentration x Molar mass

• B) Mass = Concentration x Volume

• C) Mass = Molar mass x Volume

• D) Mass = Concentration / Volume

What does the term "molar volume of a gas" refer to in chemistry?

• A) The volume of any gas at standard temperature and pressure (STP).

• B) The volume of 1 gram of a gas at any given condition.

• C) The volume of 1 mole of the gas at a specific set of conditions.

• D) The volume of a gas under extreme pressure conditions.

What is the molar volume of a gas at standard temperature (25°C or 298K) and pressure (1 atm)?

• A) 1 dm^3 mol^(-1)

• B) 12 dm^3 mol^(-1)

• C) 24 dm^3 mol^(-1)

• D) 48 dm^3 mol^(-1)

When 11.2 g of iron reacted with excess chlorine, 32.0 g of iron (III) chloride were formed. What is the balanced chemical equation for this reaction, and how would you calculate the amount of iron (in moles) that reacted?

• A) Balanced equation: Fe + Cl2 → FeCl2; Calculate moles of iron using 11.2 g / molar mass of Fe.

• B) Balanced equation: Fe + Cl2 → FeCl3; Calculate moles of iron using 11.2 g / molar mass of Fe.

• C) Balanced equation: Fe2O3 + Cl2 → 2FeCl3; Calculate moles of iron using 32.0 g / molar mass of Fe.

• D) Balanced equation: Fe + O2 → Fe2O3; Calculate moles of iron using 11.2 g / molar mass of Fe.

  Correct Answer: B) Balanced equation: Fe + Cl2 → FeCl3; Calculate moles of iron using 11.2 g / molar mass of Fe.

Given that 11.2 g of iron reacted with excess chlorine to produce 32.0 g of iron (III) chloride, what is the balanced chemical equation for this reaction, and how would you calculate the amount of iron (III) chloride (in moles) that formed?

• A) Balanced equation: Fe + Cl2 → FeCl2; Calculate moles of FeCl2 using 32.0 g / molar mass of FeCl2.

• B) Balanced equation: Fe + Cl2 → FeCl3; Calculate moles of FeCl3 using 32.0 g / molar mass of FeCl3.

• C) Balanced equation: Fe2O3 + Cl2 → 2FeCl3; Calculate moles of FeCl3 using 32.0 g / molar mass of FeCl3.

• D) Balanced equation: Fe + O2 → Fe2O3; Calculate moles of Fe2O3 using 32.0 g / molar mass of Fe2O3.

Given the balanced equation: 2Fe + 3Cl2 → 2FeCl3, and knowing that 11.2 g of iron reacted with excess chlorine, how would you calculate the amount of iron (III) chloride (FeCl3) that formed (in moles)?

• A) Multiply the mass of iron by 2 and divide by the molar mass of FeCl3.

• B) Multiply the mass of iron by 3 and divide by the molar mass of FeCl3.

• C) Multiply the mass of iron by 2 and divide by the molar mass of Fe.

• D) Multiply the mass of iron by 3 and divide by the molar mass of Cl2.

According to the following equation: CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (g), what volume of oxygen at standard temperature and pressure (STP) is required to completely burn 6 dm^3 of methane (CH4) gas?

• A) 3 dm^3 of oxygen

• B) 12 dm^3 of oxygen

• C) 6 dm^3 of oxygen

• D) 24 dm^3 of oxygen