Chemical Analysis

Question 1

What is a pure substance?

Answer 1

A substance that consists of only one element or only one compound.

Question 2

A mixture consists of _____________________ substances, not ____________________ together

Answer 2

two or more different
chemically joined

Question 3

How do you test for a pure substance and why?

Answer 3

By measuring its melting temperature.

A pure substance has a distinct melting point.

Question 4

Pure substances have a ___________ melting point but mixtures melt over a __________ of temperatures.

Answer 4

distinct

range

Question 5

An impure substance would produce a __________________________ as it freezes.

Answer 5

gradual fall in temperature

Question 6

What is a formulation?

Answer 6

A mixture which has been designed as a useful product.

Question 7

Test for oxygen:
If oxygen is present in a test tube, a _________________ when it is held inside.

Answer 7

glowing splint relights

Question 8

Test for hydrogen:
If hydrogen is present in a test tube, a lighted splint held near __________ with a _______________.

Answer 8

ignites
squeaky pop

Question 9

Test for carbon dioxide:
If carbon dioxide is _________________________, the limewater turns ______________.

Answer 9

bubbled through limewater
milky white

Question 10

Test for chlorine:
Damp ___________________ is _________________ when placed in chlorine.

Answer 10

blue litmus paper
bleached white

Question 11

Test for water:
Add water to ____________________________.
If water is present, the colour will change from __________________.

Answer 11

anhydrous copper sulfate
white to blue