Thermal Energy
What are the three main ways thermal energy can be transferred?
Conduction, convection, and radiation
What is a synthetic material? Give one example.
A human-made material; examples include plastic, nylon, or polyester
Name two signs that a chemical reaction may have occurred
Any two: gas production, temperature change, precipitate formation, unexpected color change, or light production
What are the three main subatomic particles found in an atom?
Protons, neutrons, and electrons
A metal bench feels colder than a wooden bench on the same chilly day. If both are at the same temperature, why does the metal feel colder?
Metal transfers thermal energy away from your skin faster than wood does
What type of heat transfer occurs when a metal spoon gets hot in a pot of soup?
Conduction
What natural resource is commonly used to make many plastics?
Petroleum (crude oil) or natural gas
When vinegar and baking soda are mixed, what gas is produced?
Carbon dioxide
Which subatomic particle has a positive charge?
Proton
You cut a sheet of paper into 20 tiny pieces. Did you change the paper physically or chemically?
Physical change; the paper's size and shape change, but its composition stays the same
What is the name of the process in which warm air rises and cool air sinks?
Convection
Why are synthetic materials often used to make raincoats?
They resist water and help keep the wearer dry
If a piece of paper burns and becomes ash, is this a physical change or a chemical change?
Chemical change
Where are protons and neutrons located in an atom?
In the nucleus
A balloon expands when warmed. What happens to the motion of the gas particles inside it?
They move faster on average as their thermal energy increases
Which substance usually heats up faster: water or sand?
Sand, under comparable conditions, generally heats up faster
What is one environmental problem caused by plastic waste?
Pollution, harm to wildlife, or long-lasting waste in the environment.
True or False: A color change can be evidence of a chemical reaction.
True, although color change alone does not prove a chemical reaction
What determines which element an atom is?
The number of protons
Two objects have the same volume, but one has more mass. Which object has the greater density?
The object with more mass has greater density
True or False: Heat naturally flows from a warmer object to a cooler object.
True
Is nylon a natural material or a synthetic material?
Synthetic
If ice melts into liquid water, has a new substance formed? Why or why not?
No; melting is a physical change; the substance remains water
An atom has 8 protons, 8 neutrons, and 8 electrons. What element is it, and what is its overall electrical charge?
Oxygen, neutral overall charge because it has equal numbers of protons and electrons
A mystery substance cannot be broken down into simpler substances by ordinary chemical means. What type of substance is it?
An element