Busy. Please wait.

show password
Forgot Password?

Don't have an account?  Sign up 

Username is available taken
show password


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.

Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
Don't know
remaining cards
To flip the current card, click it or press the Spacebar key.  To move the current card to one of the three colored boxes, click on the box.  You may also press the UP ARROW key to move the card to the "Know" box, the DOWN ARROW key to move the card to the "Don't know" box, or the RIGHT ARROW key to move the card to the Remaining box.  You may also click on the card displayed in any of the three boxes to bring that card back to the center.

Pass complete!

"Know" box contains:
Time elapsed:
restart all cards
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Chemistry revision

Hard and Soft water

What two main compounds are found in hard water? Magnesium and Calcium.
What is temporary hardness? The property of hard water that can be removed by boiling the water.
What is permanent hardness? The property of hard water that cannot be removed by boiling the water.
What is the problem with hard water? Hard water wastes soap by producing scum that must be rinsed off.
How do you 'soften' permanently hard water? By using an ion exchange column.
What is an ion exchange column? A device used to soften hard water. Contains a resin with an excess of Sodium (Na+)ions. When the water passes through the column the Calcium (Ca2+) ions are exchanged for Sodium ions
Why does ion exchange soften all types of water, while boiling on removes temporary hardness. Because an ion exchange swaps Calcium ions with Sodium ions, meaning the Calcium ions aren't there anymore. The water is no longer hard.
Created by: elisa1011