Chemical Changes, Molecules, and Compounds

Evidence of a chemical reactions is anything that shows - 

• a new substance has formed
• a solid dissolved in a liquid
• interaction between 2 gases
• a change in the state of matter

Tags

NGSS.MS-PS1-2

One of the signs of a chemical reaction taking place is:

• Bubbles are produced 
• Reactants are not combining
• Products are not forming
• Color is not changing

Tags

NGSS.MS-PS1-2

Which of the following is an example that includes evidence of a chemical reaction?

• A sample of zinc is placed in water and it settles to the bottom
• A solid block of ice is heated and it completely melts into a liquid. 
• Sugar that is burned gives off an odor and turns brown and then black.
• A tomato is placed into a blender and chopped up into smaller pieces.

Tags

NGSS.MS-PS1-2

Hydrogen is a pure substance represented by the chemical symbol H. Which of the following best describes hydrogen?

• Hydrogen is an element made of two or more kinds of atoms.
• Hydrogen is a compound made of only one kind of atom.
• Hydrogen is a compound made of two or more kinds of atoms.
• Hydrogen is an element made of only one kind of atom.

Tags

NGSS.MS-PS1-1

What is a compound?

• an atom with more electrons than protons
• a substance in which the atoms of two or more elements are combined together
• an atom with more neutrons than protons
• a substance in which the atoms of three or more elements are combined together

Tags

NGSS.MS-PS1-1

Atoms combine to form _______. 

• electrons
• molecules
• nuclei
• neutrons

Tags

NGSS.MS-PS1-1

Two or more atoms joined together make up a _____.

• compound
• molecule
• solution

Tags

NGSS.MS-PS1-1

Oxygen in the air combines with iron molecules on a frying pan to form _______. 

• chemical property
• physical property
• rust

Which of these is an example of a compound?

• iron
• calcium
• rust

The smallest particle of any particular type of matter is known by which of the following terms?

• Element
• Chemical
• Atom
• Substance

Tags

NGSS.MS-PS1-1