Phase Changes in Matter

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Questions and Answers

What is the charge of an electron?

Positive charge

Neutral charge

No charge

Negatively charged (correct)

Which formula correctly calculates the number of neutrons in an atom?

Atomic mass + Number of protons

Number of protons + Neutrons

Atomic mass - Number of protons (correct)

Number of protons - Atomic mass

In a chemical equation, what do the reactants represent?

Elements or compounds that exist prior to a reaction (correct)

New substances after the reaction

Atoms that must be created

The coefficients of the products

Which statement is true about balancing chemical equations?

The number of atoms must be equal on both sides of the arrow. Signup and view all the answers

What does the coefficient in a chemical equation signify?

The number of molecules present in the reaction Signup and view all the answers

How does an increase in temperature typically affect the speed of molecules?

It increases the speed of molecules. Signup and view all the answers

What effect does a weak molecular attraction between molecules have on phase change?

It makes phase change easier. Signup and view all the answers

What do we call molecules that 'move around each other'?

Liquid molecules. Signup and view all the answers

During a chemical reaction, what happens to the reactants?

They rearrange to form products. Signup and view all the answers

What defines an atom's identity?

The number of protons it contains. Signup and view all the answers

What is true about atoms during a chemical reaction?

Atoms rearrange to form new groups. Signup and view all the answers

What role do neutrons play in the structure of an atom?

They contribute to atomic mass without affecting charge. Signup and view all the answers

Which statement about molecules in a solid state is correct?

They vibrate in fixed positions. Signup and view all the answers

What describes the movement of molecules in a solid?

The molecules vibrate in place without moving around. Signup and view all the answers

How does temperature relate to the kinetic energy of molecules?

Higher temperatures correspond to higher average kinetic energy. Signup and view all the answers

What is required for a phase change to occur in a substance?

An increase or decrease in the molecules' kinetic energy. Signup and view all the answers

Which statement regarding molecular attraction is accurate?

Molecular attraction is a fixed property of a substance. Signup and view all the answers

What happens when energy is transferred to a substance?

The kinetic energy of the molecules increases. Signup and view all the answers

Which phase of matter has molecules that can slide past one another?

Liquid Signup and view all the answers

When does a liquid turn into a gas?

When its kinetic energy overcomes molecular attraction. Signup and view all the answers

What effect does decreasing the temperature have on a gas?

It may cause a phase change to a liquid as molecular attraction increases. Signup and view all the answers

Study Notes

Phase Changes

Phases of matter include solid, liquid, and gas
Molecules in a solid are in fixed positions, only vibrating
Molecules in a liquid can move around each other
Molecules in a gas can move freely and are far apart
A phase change occurs when molecules change their freedom of movement due to energy transfer
Temperature is a measure of the average kinetic energy of molecules
Increasing energy increases the kinetic energy
Increasing kinetic energy can overcome attractive forces between molecules, leading to a phase change
Decreasing kinetic energy can allow attractive forces to pull molecules together, leading to a phase change

Example Question

A sealed jar of water was solid outside. After twelve hours, the jar of water was liquid. This is a phase change.
Molecules in the solid were in place and vibrating.
Molecules in the liquid were moving around each other
When the molecules received more energy, they were able to move around each other (from solid to liquid).
Increasing energy speeds up the motion of molecules
Adding energy to a substance changes its phase
Subtracting energy from a substance changes its phase

Chemical Reactions

Atoms and molecules rearrange to form new substances
Atoms remain the same elements, no atoms are destroyed or created during rearrangements
In chemical reaction, reactants turn into products via the rearrangement of atoms
Reactants exist before the reaction and are written on the left side of the arrow
Products are formed after the reaction and are on the right side of the arrow
The arrow signifies that a reaction has occurred
Different substances have unique properties that result from the way atoms are arranged

Atoms

Atoms are basic building blocks of matter
Atoms consist of protons, neutrons, and electrons
Protons have a positive charge
Neutrons have no charge
Electrons have a negative charge
Protons and neutrons are located in the nucleus of the atom
Electrons orbit the nucleus in electron shells
The number of protons defines the element
Atoms are not created or destroyed in a chemical reaction
The number of protons define an element

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Description

Explore the fascinating world of phase changes in matter through this quiz. Understand how energy transfer affects the state of molecules in solids, liquids, and gases. Test your knowledge on how temperature and kinetic energy influence these transitions.