Other Chemistry Answers

The standard enthalpy of a reaction can be ___________.

a. calculated as the sum between the difference of the standard molar enthalpies of formation of products only.

b. obtained as the difference between the sum of the standard molar enthalpies of formation of products and reactants.

c. calculated as the difference between the sum of the standard molar enthalpies of formation of reactants only.

d. obtained from the different thermochemical equations by applying the first law of thermodynamics.

The heat capacity of a substance is determined ______________.

a. by a constant specific heat values regardless of physical states.

b. through careful measure of specific heat values.

c. through calorimetry.

d. by increasing the temperature by 1°C.

Heat is a form energy transfer between objects as an effect of their difference in _________.

a. volume

b. energy

c. pressure

d. temperature

The first law of thermodynamics hints that __________.

a. net energy flow to or from any system comes from the surroundings.

b. net heat flow to or from any system comes in either energy or work.

c. net energy flow to or from any system comes in either heat or work.

d. net energy flow to or from any surroundings comes in either heat or work.

The amount of heat absorbed or released by a chemical reaction at constant atmospheric pressure .

a. enthalpy of reaction

b. enthalpy of products

c. enthalpy

d. standard molar enthalpy

Thermal decomposition of limestone to form calcium oxide and carbon dioxide is ________.

a. partly exothermic

b. exothermic

c. endothermic

d. both endothermic and exothermic

if a 0.22560g of sodium bicarbonate is titrated with 0.1165N sulphuric acid. what volume of acid is required to reach the end point?

Treatment of a 0.2500g sample of impure potassium chloride with an excess of AgNO3 resulted in the formation of 0.2912 g of AgCl (74.55 g/mol). Calculate the percentage of KCl (143.32 g/mol) in the sample

Define the term preformulation and explain the parameters to be considered in preformulation studies

1,Lisa consumes a total of 8700 kilojoules per day and her diet consists of 55% of carbohydrates. Calculate the quantity of carbohydrates that her diet provides per day in grams and choose the correct answer.

a.81 g

b.4785kJ

c.281 g

d.106 g

2.Mr Naidoo consumes 157 g of carbohydrates, 107 g of fat and 238 g of protein per day. Calculate the energy provided by each of the energy-yielding nutrients.

a.Protein = 238kJ; Carbohydrates = 157kJ and Fat = 107kJ

b.Protein = 4046kJ; Carbohydrates = 2669kJ and Fat = 4066kJ

c.Protein = 4046kJ; Carbohydrates = 2669kJ and Fat = 1819kJ

d.Protein = 4046kcal; Carbohydrates = 2669kcal and Fat = 4066kcal

If the empirical formula of a compound is P₂O₃, and it has a molecular weight equal to 220 g/mol, what is its molecular formula?

When isopropanol (C3H80) burns in oxygen, carbon dioxide, water and heat are produced.

1. To which class does each enzyme belong? Explain your answers.

a.) pyruvate decarboxylase

b.) alanine aminotransferase

c.) alcohol dehydrogenase

d.) hexokinase

Calculate the molarity of a solution containing 2.8 moles of ethyl alcohol (C₂H6O) in 500mL of solution.