Other Chemistry Answers

Hess’s law states that the __________________.

a. enthalpy of a sum of a series of reactions is equal to the sum of the enthalpies of those two reactions.

b. enthalpy of a sum of two reactions is equal to the difference of the enthalpies of those two reactions.

c. enthalpy of a sum of a series of reactions is equal to the sum of the heat capacities of those two reactions.

d. enthalpy of a sum of a series of reactions is unequal to the sum of the enthalpies of those two reactions.

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

a. volume

b. energy

c. pressure

d. temperature

Calorimetry involves the measurement of the ___________________.

a. quantity of heat exchanged between a system and the surroundings.

b. quantity of work exchanged between a systems.

c. quantity of work exchanged between a system and the surroundings.

d. quantity of heat exchanged between the systems.

Explosion of a firecracker triggered by a spark is _________.

a. endothermic

b. exothermic

c. partly exothermic

d. both endothermic and exothermic

Enthalpy of reaction is positive when _______________.

a. chemical reaction is endothermic.

b. chemical reaction is both endothermic and exothermic.

c. chemical combustion does not happen.

d. the amount of heat transferred and absorbed are unequal.

Law of Conservation of Energy states that, ______________.

a. Energy can neither be created nor destroyed.

b. The change in energy of a system is equal to the heat absorbed and released.

c. The energy of the system and the of the surroindings are unrelated.

d. Energy can neither be created nor transferred.

When work is accomplished on the system, it _________

a. gains work and energy is denoted as positive.

b. gains energy and work is denoted as positive.

c. gains work and energy is denoted as zero.

d. gains energy and work is denoted as negative.

A calorimeter is an____________________.

a. apparatus that has water or any liquid with unknown heat capacity.

b. insulated coffee cup that that transfers an immense amount of heat.

c. excellent insulator that works without a thermometer.

d. insulated apparatus that contains water or any liquid of known heat capacity.

The study of energy and heat flow that goes with a chemical reaction and physical transformation.

a. Thermodynamics

b. Enthalpy

c. Conservation of Energy

d. Thermochemistry

The symbol, q-, means ___________.

a. Work is done on the surroundings.

b. Heat flows from the system to the surroundings.

c. Work is done on both the system and the surroundings.

d. Heat flows from the surroundings to the system.

The amount of energy needed to increase the temperature of a material by 1°C.

a. coffee cup calorimeter

b. heat constant

c. specific heat transfer

d. heat capacity

When heat flows from the system to its surroundings, heat is ________.

a. positive

b. negative

c. equal

d. neutral

It shows the value and direction of heat involved in a reaction.

a. thermochemical reaction

b. enthalpy of reaction

c. thermochemical equation

d. enthalpy

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