Chemistry Around Us
What is Chemistry?
This branch of science studies matter, its composition, structure, properties, and the changes it undergoes
Anything that has mass and takes up space is what?
Matter
This is the name for matter changing from one state to another while remaining the same kind of substance.
Phase changes of matter
A change in which a substance absorbs heat energy from its surroundings
A property that can be observed or measured without changing what a substance is made of is this kind of property.
Physical Properties
A scientist studies the chemical substances found in living organisms, such as the processes happening inside the human body. Which branch of chemistry is this?
Biochemistry?
A substance has a definite volume but takes the shape of its container. The particles in this state of matter can slide past one another. What state of matter is it?
Liquid State
Wet clothes dry outside even when the water never reaches its boiling point. What process causes this? And what states involve in this process
Evaporation
Liquid-> Gas
When water freezes into ice, heat energy is released to the surroundings. Is this endothermic or exothermic?
Exothermic Change
The ability of paper or wood to burn is an example of this type of property.
Flammability (Chemical Property)
A scientist examines a sample of water to identify which substances are present and how much of each substance it contains. Which branch of chemistry is being used?
Analytical Chemistry
A substance has no definite shape or volume. Its particles are very far apart and move freely in all directions. Identify this state of matter.
Gas
Frost forms directly from water vapor in the air without first becoming liquid water. Name this phase change. Also which two states involve in this process?
Deposition
Gas → Solid
A student places chocolate in sunlight. The chocolate melts and absorbs heat from its surroundings. What type of energy change is occurring?
Endothermic Change
A student tears a piece of paper into four small pieces. Is this a physical or chemical change? Explain why.
Physical change because the paper changes size and shape, but no new substance forms.
A scientist studies carbon-containing compounds used in plastics, fuels, and medicines. Which branch of chemistry is this?
Organic Chemistry
The Sun and lightning are examples of this state of matter. It contains positively charged ions and free electrons. What is it?
Plasma
Dry ice changes directly from a solid into a gas without becoming a liquid. What is this process called? Also which two states involve in this process?
Sublimation
Solid → Gas
When water boils on a stove, its particles gain energy and move faster. Is this endothermic or exothermic, and what happens to the particles?
Endothermic; particles gain energy and move faster.
An iron nail reacts with oxygen and water to form rust. Identify the chemical property that allows this reaction to happen.
Rusting (Ability to rust)
A scientist investigates the physical properties of a substance and the energy changes that happen during a chemical reaction. Which branch of chemistry is this?
Physical Chemistry
What are the main factors/reasons that causes states changes
Temperature and Pressure
A gas gains a large amount of energy and becomes plasma. When plasma loses energy, it changes back into a gas. Name BOTH processes in the correct order.
1. Ionization
2. Recombination.
Two substances undergo different changes. Substance A absorbs heat and its surroundings become cooler. Substance B releases heat and its surroundings become warmer. Identify both types of changes and explain the direction of energy transfer.
A is Endothermic (energy enters the substance). B is Exothermic (energy exits the substance).
A student is given two mystery substances. Substance A can be measured for density without changing its identity. Substance B is tested for its ability to react with another substance. Which substance is being tested for a physical property and which for a chemical property? Explain the difference.
Substance A: Physical property.
Substance B: Chemical property.