Physical & Chemical Changes
Changes the form or appearance of a substance but does not create a new substance.
What is a physical change?
A pure substance made of only one kind of atom.
What is an element?
The basic SI unit used to measure mass.
What is the kilogram?
A change that absorbs heat energy from the surroundings.
What is an endothermic change?
A process scientists use to investigate questions and solve problems.
What is the scientific method?
A change that produces one or more new substances with different properties.
What is a chemical change?
Two or more atoms chemically bonded together.
What is a molecule?
The basic SI unit used to measure length.
What is the meter?
A change that releases heat energy to the surroundings.
What is an exothermic change?
A testable explanation for a scientific question that can be supported or rejected through experimentation.
What is a hypothesis?
What are examples of chemical changes?
The two types of pure substances are elements and these.
What is a compound?
This is 253 mL expressed in liters.
What is 0.253 L?
In Q = mcΔT, this variable represents mass and is measured in grams.
What is mass, measured in grams?
This step of the scientific method involves collecting information and observations to help answer a scientific question.
What is research?
Color change, gas production, and formation of a solid are signs that this type of change probably occurred.
What are two signs that a chemical change probably occurred?
Atoms are the building blocks of matter, while these are made when atoms bond together.
How are atoms and molecules related?
The number of significant figures in 0.025 L.
What are two significant figures?
In Q = mcΔT, this variable represents specific heat capacity and has units of J/g°C.
What is specific heat capacity, measured in J/g°C?
This is the variable that a scientist purposely changes during an experiment.
What is the independent variable?
Cooking an egg is this type of change because new substances form and the change cannot easily be reversed.
What is a chemical change, and why is cooking an egg an example?
During a physical change, this property of matter remains the same if no matter is added or lost.
Does mass remain the same during a physical change, and what is an example?
32,068 km rounded to 3 significant figures.
What is 32,100 km, or 3.21 × 10⁴ km?
The amount of heat needed to heat 100.0 g of water from 1°C to 37°C when c = 4.18 J/g°C.
What is 15,048 J, or approximately 15.0 kJ?
This is the variable that is measured or observed to determine the effect of the independent variable.
What is the dependent variable?