Which of the following is the best interpretation of the First Law of Thermodynamics?

a) The total work of the universe is decreasing.

b) The total mass of the universe is increasing.

c) The total energy of the universe is constant.

d) The total heat of the universe is decreasing.

e) The total enthalpy of the universe is increasing.

f) The total entropy of the universe is constant.

Determine whether the following is endothermic or exothermic:

The reactants have lower energy levels than the products.

Phosphorus trichloride is formed when diphosphorus reacts with chlorine gas. The reaction equation is P₂ + 3 Cl₂ → 2 PCl₃. Calculate the ΔH for the reaction (in kcal and in kJ) using the bond dissociation energies in the table below.

Acetylene (C₂H₂) is a gas used for welding. Combustion of acetylene releases 1301.1 kJ/mol. Calculate the energy (in kilojoules) released in burning 65.0 g acetylene.

A sample of an alloy weighing 65.00 g with a temperature of 90.00°C is dropped into 120.0 g of water at 25.00°C. The final temperature of both the alloy and the water is 40.00°C. Calculate the specific heat capacity of the alloy if the specific heat of water is 4.184 J/(g•°C).

What is the minimum energy required for a chemical reaction to occur?

True or False. Chemical equilibrium occurs when reactants and products have equal amounts and there is no net change in concentration.

The following conversion has an equilibrium constant (K_c) of 1.1 × 10⁻³ at 1280 °C.

Br₂ (g) ⇌ 2 Br (g)

Determine whether the reactant or the product is favored at equilibrium. 

Consider the following gas-phase reaction:

H₂(g) + Br₂(g) ⇌ 2 HBr(g);      ΔH = –72.6 kJ

If the temperature changes, which reaction characteristics will be affected?

I. Equilibrium concentrations

II. Equilibrium constant

Given the following compounds with their K_sp values, choose the compound that will have the highest molar solubility in pure water.

What conditions must be satisfied for a chemical reaction to occur spontaneously?

Determine the system whose entropy is increasing. 

Identify the true statement from the following statements on factor/s affecting the spontaneity of a reaction.

The following figure is the phase diagram for water.

How is skating on ice, which is solid water, possible?

Which of the statements below is a postulate of the kinetic molecular theory of gases?

Explain what is wrong with the expression below and write the correct version: 

At 298 K and 723 torr, a sample of nitrogen has a volume of 38.55 mL. If the pressure is increased to 925 torr at a constant temperature, what volume would nitrogen occupy?

How does the application of force to the person's waist during the Heimlich maneuver create enough pressure to expel an obstruction from the trachea?

A cylinder with a movable piston contains a mixture of argon and xenon gas with partial pressures of 0.80 atm and 1.20 atm, respectively. Choose the diagram that represents the change in volume when the argon gas is removed from the cylinder at constant temperature and pressure.

The image below is a representation of a gas sample at 1 atm and 28 °C in a 2 L container. 

Sketch a similar image representing the scenario where the size of the container is increased to 4 L and the temperature is decreased to 0 °C

How would this change affect the pressure?

Oxygen gas reacts with methane (CH₄) to produce carbon dioxide and water. 

Calculate the moles of O₂ required to completely react with 121.0 L of methane at STP