Introduction to Chemistry

A researcher is analyzing a sample to determine the exact amounts of various pollutants present. Which branch of chemistry is most directly involved in this task?

Which of the following is an example of a compound?

In a chemical reaction, 2 grams of hydrogen react with 16 grams of oxygen to produce 18 grams of water. Which scientific law does this observation primarily support?

If a container of gas is heated, what happens to the gas particles inside the container?

A chemist is studying the rate at which a reaction proceeds and the energy changes involved. Which branch of chemistry is this?

How many moles are present in 12.044 x $10^{23}$ molecules of $CO_2$?

Which state of matter is characterized by having a definite volume but no definite shape?

What is the molar mass of water ($H_2O$)? (Assume the molar mass of H is 1 g/mol and O is 16 g/mol)

In a chemical reaction, 20g of reactant A is mixed with 30g of reactant B. After the reaction, it is found that reactant A is completely consumed, while some of reactant B remains. What is the limiting reactant?

A solution is prepared by dissolving 116.88g of NaCl (molar mass = 58.44 g/mol) in enough water to make 2.0 L of solution. What is the molarity of the solution?

Which statement accurately describes the behavior of acids and bases according to the Bronsted–Lowry definition?

Which type of chemical bond is characterized by the sharing of electrons between two nonmetal atoms?

For a certain reaction, $\Delta H = -100 \text{ kJ}$ and $\Delta S = -50 \text{ J/K}$ at 300 K. Calculate the Gibbs Free Energy ($\Delta G$) and determine if the reaction is spontaneous or non-spontaneous.

Consider the reaction $A + 2B \rightarrow C$. Which change will increase the reaction rate?

Consider the reversible reaction: $N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g) + \text{heat}$. According to Le Chatelier's Principle, which change will shift the equilibrium to the right, favoring the production of $NH_3$?

In an electrochemical cell, the oxidation process occurs at which electrode?

A radioactive isotope has a half-life of 10 years. If you start with a 100 gram sample, how much of the isotope will remain after 30 years?

Which process is characterized by the combination of light nuclei to form a heavier nucleus?