Atoms and Molecules

Jaleesa draws a model of a chemical reaction between two substances. She uses a black circle to represent one kind of atom and a white circle to represent another kind of atom. Which model shows that a chemical reaction takes place and that mass is conserved?

• A
• B
• C
• D

Tags

NGSS.HS-PS1-7

A combustion reaction occurs between one molecule of methane (CH₄ ) and TWO molecules of oxygen (O₂ ). How many atoms of carbon, hydrogen, and oxygen make up the products for this combustion reaction?

• 1 carbon, 1 hydrogen, and 1 oxygen
• 1 carbon, 1 hydrogen, and 2 oxygen
• 1 carbon, 4 hydrogen, and 2 oxygen
• 1 carbon, 4 hydrogen, and 4 oxygen

Tags

NGSS.HS-PS1-7

Which of the following correctly balances the equation?

• A
• B
• C
• D

Tags

NGSS.HS-PS1-7

The model shown represents one molecule of hydrazine, a chemical in rocket fuel. The black spheres represent nitrogen atoms, and the white spheres represent hydrogen atoms. Based on the model, what is the atomic composition of hydrazine?

• 1 atom of nitrogen and 1 atom of hydrogen
• 4 atoms of nitrogen and 2 atoms of hydrogen
• 2 atoms of nitrogen and 2 atoms of hydrogen
• 2 atoms of nitrogen and 4 atoms of hydrogen

Tags

NGSS.MS-PS1-1

In a chemical formula, the number of each type of atom in the compound is shown with numbers that are ____.

• superscripts
• chemical symbols
• oxidation numbers
• subscripts

Ethanol has six hydrogen atoms, two carbon atoms, and one oxygen atom. Which is the correct chemical formula of the model below?

• C₂H₆O
• 2CH₆O
• 6HCO
• C₂6HO

Tags

NGSS.MS-PS1-1

What are the missing coefficients for the unbalanced equation below? AlCl₃ + NaOH --> Al(OH)₃ + NaCl

• 1,3,1,3
• 3,1,3,1
• 1,1,1,3
• 1,3,3,1
• 3,1,1,1

Tags

NGSS.HS-PS1-7

In general, metals are ____ since they are composed of individual atoms or small molecules packed tightly together.

• poor conductors of heat
• brittle
• poor conductors of electricity
• good conductors of heat

Aspartame is an artificial sweetener; its formula is C₁₃H₁₆N₂O₅. What element in the formula has the most number of atoms?

• carbon
• hydrogen
• oxygen
• nitrogen

Tags

NGSS.MS-PS1-1

The table shows three models that represent a different molecule each. Information on each molecule is given in the table. Oxygen is represented by:

• White sphere
• Gray sphere
• Striped sphere
• Dotted sphere

Tags

NGSS.MS-PS1-1