Physical vs. Chemical Properties
What is a physical property?
A characteristic that can be observed or measured without changing the identity of the substance.
What is the most important clue that a chemical change has occurred?
A new substance has formed.
How are particles arranged and moving in a solid?
They are packed closely together and vibrate in place.
What happens to the motion of particles when thermal energy is added?
The particles move faster.
What is density?
The amount of mass in a given volume.
Scientists are given an unknown substance. Why can physical and chemical properties help them identify it?
Each substance has a unique set of physical and chemical properties.
Is density a physical property or a chemical property?
Physical property.
Ice melts into liquid water. Is this a physical or chemical change?
Physical change.
How are particles arranged and moving in a liquid?
They are close together but can move or slide past one another.
What happens to the motion of particles when thermal energy is removed?
The particles move slower.
What happens when liquids with different densities are poured together?
They form layers based on density.
Two white powders look exactly the same. One reacts with water and produces bubbles while the other only dissolves. What property could scientists use to tell them apart?
Their reactivity with water.
Is flammability a physical property or a chemical property?
Chemical property.
An egg cooks in a frying pan. Is this a physical or chemical change?
Chemical change.
How are particles arranged and moving in a gas?
They are far apart and move rapidly.
What phase change occurs when a liquid changes into a gas?
Vaporization.
Which will be on top in a density column: the substance with the highest density or the lowest density?
The substance with the lowest density.
A substance disappears when stirred into water and no new substance forms. What physical property is being tested?
Solubility
A scientist observes the color, texture, and odor of an unknown substance. What type of properties are being observed?
Physical properties.
Salt dissolves completely in water. Is this a physical or chemical change?
Physical change.
Which state of matter has a definite shape and a definite volume?
Solid.
What phase change occurs when a gas changes into a liquid?
Condensation.
Four liquids have densities of 0.80, 0.95, 1.10, and 1.40 g/cm³. Which liquid will be on the bottom?
The liquid with a density of 1.40 g/cm³.
A student mixes a substance with vinegar and bubbles form. What evidence suggests that a chemical reaction occurred?
A gas was produced.
A substance reacts with water and produces a gas. Is this showing a physical or chemical property?
Chemical property.
Two clear liquids are mixed and a solid precipitate forms. Is this a physical or chemical change?
Chemical change.
Which state of matter has a definite volume but takes the shape of its container?
Liquid.
Water is heated until it boils. What happens to the average kinetic energy of its particles as it is heated?
It increases.
A graduated cylinder starts with 12 mL of water. After a rock is added, the water level rises to 17 mL. What is the volume of the rock?
5 mL.
A student repeats an investigation several times while testing TWO variables. The experiment failed differently each time. What was wrong with this experiment?
Testing more than one variable.
What is the main difference between a physical property and a chemical property?
A physical property can be observed without changing the substance's identity. A chemical property describes the substance's ability to react and form new substances.
Name TWO observations that can provide evidence that a chemical reaction occurred.
formation of a precipitate, unexpected color change, production of a gas, temperature change, light, or a new odor.
Which state of matter has particles that are farthest apart and moving the fastest: solid, liquid, or gas?
Gas
During vaporization, what happens to the kinetic energy and arrangement of the particles?
Kinetic energy increases, and the particles become less compact/spread farther apart.
A liquid has a density of 0.85 g/cm³ and another has a density of 1.20 g/cm³. Which one will float on top?
The liquid with a density of 0.85 g/cm³
A student wants to determine whether mixing two substances forms a new substance. What should the student look for?
Evidence of a chemical reaction, such as gas production, a precipitate, unexpected color change, temperature change, light, or a new odor.