Mixtures, Atomic Structure, Chemical Bonds and Equations

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Questions and Answers

Explain how the properties of a homogeneous mixture differ from those of a heterogeneous mixture, providing an example of each.

Homogeneous mixtures have uniform composition throughout, like saltwater. Heterogeneous mixtures do not have uniform composition, like sand and water.

Describe how the atomic number and mass number of an atom are related, and explain what isotopes are.

The atomic number is the number of protons, defining the element. The mass number is the sum of protons and neutrons. Isotopes are atoms of the same element with different numbers of neutrons.

Explain, in terms of electron transfer or sharing, the fundamental difference between ionic and covalent bonds.

Ionic bonds involve the transfer of electrons between atoms, creating ions. Covalent bonds involve the sharing of electrons between atoms.

If a balloon is filled with 5 moles of helium gas at standard temperature and pressure (STP), what volume will the balloon occupy? (Assume ideal gas behavior, where 1 mole of any gas occupies 22.4 L at STP)

The balloon will occupy 112 L. This is calculated by multiplying 5 moles by 22.4 L/mole. Signup and view all the answers

Describe the relationship between reactants, products, and a balanced chemical equation. Why is it important for chemical equations to be balanced?

Reactants are substances that undergo change, and products are the substances formed. A balanced chemical equation represents the reaction with correct formulas and coefficients. Balancing ensures the law of conservation of mass is followed. Signup and view all the answers

Explain the concept of a limiting reactant in a chemical reaction and describe its effect on the amount of product formed.

The limiting reactant is the reactant that is completely consumed in a reaction, determining the maximum amount of product that can be formed. The other reactants are in excess, and once the limiting reactant is used up, the reaction stops. Signup and view all the answers

How does the periodic table organize elements, and what is the significance of elements within the same group (vertical column)?

The periodic table organizes elements by atomic number and recurring chemical properties. Elements in the same group have similar chemical properties due to having the same number of valence electrons. Signup and view all the answers

What is molarity, and how is it used to express the concentration of a solution? Give the equation for calculating molarity.

Molarity (M) is a measure of concentration, defined as moles of solute per liter of solution and it is calculated using the equation: $M = \frac{moles \ of \ solute}{liters \ of \ solution}$ Signup and view all the answers

Explain the relationship between pH, acids, and bases. How does pH relate to the concentration of hydrogen ions (H+) in a solution?

pH is a measure of acidity or basicity. Acids have a pH less than 7 (high [H+]), bases have a pH greater than 7 (low [H+]), and neutral solutions have a pH of 7. pH is the negative log of [H+]. Signup and view all the answers

State Le Chatelier's principle and provide an example of how a change in temperature can affect a system at chemical equilibrium.

Le Chatelier's principle: if a change of condition is applied to a system in equilibrium, the system will shift to relieve the stress. Ex: Increasing temp in an endothermic reaction shifts equilibrium to the product side. Signup and view all the answers

Flashcards

What is matter?

Anything that has mass and takes up space; exists as solid, liquid, gas or plasma and can be a pure substance or mixture.

What are pure substances?

Substances with a fixed composition and distinct properties; can be elements or compounds.