Purity

Pure means that every one of its atoms is exactly the same and made of just ... type of atom.

Which one is pure substance?

• NaCl

• Gold

• Pen ink

• seawater

What is the name of substance that they have variable compositions?

• pure

• mixture

• element

• compound

Which one is element?

• 
• 
• 
• 

Gold is a mixture.

• True

• False

Seawater is a mixture.

• Yes

• No

Pure gold has ... carat

• 12

• 22

• 24

• 44

What does the mean 18 carat of gold?

• has 18 parts out of 24 that are gold, 6 parts out of 24 is made up other metals

• has 6 parts out of 24 that are gold, 18 parts out of 24 is made up other metals

• has 24 parts out of 24 that are gold, 6 parts out of 24 is made up other metals

• has 6 parts out of 24 that are gold, 24 parts out of 24 is made up other metals

18 carat gold has a purity of .....

• 18%

• 24%

• 75%

• 100%

The ring contains 925 parts silver out of 1000 parts. So, it is ... pure silver.

• 925%

• 92,5%

• 100%

• 7,5%