Definitions
What is a chemical?
substances that have a definite composition
What are the three states of matter?
gas, liquid, solid
What are atoms?
The basic building blocks of matter
What is a hypothesis?
A testable prediction/explanation
If 5.046 L of water is mixed with 2.6 L of hydrogen peroxide, what is the final volume of the mixture? (Hint: Use significant figures)
7.6 L
What is the difference between a chemical change and a physical change?
Chemical changes transform one or more chemicals into new substances, while physical changes do not change the identity of a substance
Describe the particle arrangement and movement in a gas
the particles in a gas are spread far apart and move independently of one another
What is the difference between elements and compounds?
Elements are pure substances that contain only one type of atom while compounds are pure substances that contain more than one type of atom, combined into molecules
What are the steps of the scientific method?
Observe, Question, Form a hypothesis, Conduct an experiment, Analyze results, Draw conclusions, Report results
If the mass of a sample of gold is 96.6 grams and its volume is 5 cm^3, what is its density? (Hint: use significant figures)
20 g/cm^3
What is the difference between mass and weight?
Mass is the quantity of the matter contained in the object while weight measures the force of gravity acting on mass
Describe the particle arrangement and movement in a liquid
the particles in a liquid are close together, but can still slide past one another and move around
What is the difference between pure substances and mixtures?
Pure substances are substances in which the smallest unit still has the same physical and chemical properties of the whole substance while mixtures contain two or more pure substances mixed together and their smallest units do not have the same properties as the whole mixture.
What is the difference between a theory and a law?
a theory is a well-tested explanation of observations while a law is a statement or mathematical expression that reliably describes the behavior of the natural world.
a hypothesis predicts events, a theory explains events, and a law describes events
What is the difference between accuracy and precision?
Accuracy is how close a measurement is to the true or actual value while precision is how closely several measurements agree with each other
Give an example of a chemical and a physical property of something in the room
Describe the particle arrangement and movement in a solid
the particles in a solid are packed tightly together and can only vibrate in place
What is the difference between homogenous and heterogenous mixtures?
Homogenous mixtures are mixtures where the pure substances are distributed uniformly throughout and the different pure substances cannot be seen while heterogenous mixtures are not evenly mixed and clearly show the different substances
What is an independent variable?
An independent variable is what is being tested or changed during the experiment
How much heat energy is needed to heat 10.2 grams of water from 25 C to 45 C? (The specific heat capacity of water is 4.186 J/gC)
850 J
What is the difference between heat energy, kinetic energy, and temperature?
Heat is the energy transferred between objects that are at different temperatures, while Kinetic energy is the energy of motion (or the energy of an object that is in motion). Temperature measures the average kinetic energy of the movement of particles in a substance
How does temperature change when heat is added to a substance as it changes from solid to liquid to gas?
the temperature only increases when the substance is in the solid, liquid, or gas phase, and not when it is moving between phases
A compound is composed of two or more elements chemically joined together
A mixture is composed of two or more substances physically mixed together, but not chemically joined
As a result, mixtures can be separated much easier than compounds can
The properties of compounds are the same throughout while mixtures vary
The composition of compounds is uniform throughout, but mixtures can vary
What is a dependent variable?
A dependent variable is what is being measured at the end of an experiment; it depends on the independent variable
How much heat energy is needed to heat 15.5 mL of water from 0 C to 100 C? (The density of water is 1.000 g/mL and the specific heat of water is 4.186 J/gC)
6000 J