Find the average atomic mass for Cl if 75.78% of Cl atoms are ³⁵Cl with a mass of 34.96885271 amu and 24.22% are ³⁷Cl with a mass of 36.96590260 amu. (Round your answer to three decimal places.)

There are 2 isotopes of copper that occur naturally; ⁶³Cu and ⁶⁵Cu. The

⁶³Cu atoms have a mass of 62.929601 amu and the ⁶⁵Cu atoms have a mass of 64.927794 amu. What is the percent natural abundance for the ⁶⁵Cu isotope? (Round your percentage to two decimal places and include the % symbol in your answer.)

24.1% of all the isotopes of a an element have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu.
What is the average mass of this element?

• 74.92 amu
• 24.97 amu
• 75.01 amu
• 74.51 amu

Water freezing into ice is an example of a...

• Physical Change
• Chemical Change

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

Chemical or Physical?  Glass breaking into tiny shards

• Chemical Change
• Physical Change

Physical or Chemical Change?  Cutting an orange into wedges.

• Physical Change
• Chemical Change

Contains only one kind of atom.

• Element
• Compund
• Mixture

The air is a _________. 

• element 
• mixture 
• compound 
• energy 

Tags

NGSS.MS-PS1-1

Examples are milk and gasoline.

• elements
• mixtures
• compounds

Tags

NGSS.MS-PS1-1

Is sugar (C₁₂H₂₂O₁₁) an element or a compound?

• Element
• Compound

Tags

NGSS.HS-LS1-6