Unit 3 Review

Physical and Chemical Changes

100

Write an example of a physical change

check answers

200

Write an example of a chemical change.

check answers

300

Is Na (Sodium) bonding with Cl (Chlorine) an example of a physical change or chemical change and why? 

A chemical change 

- the molecular structure changed 

- a new product is formed 

400

Is mixing baking soda and vinegar an example of a physical change or a chemical change?

Chemical change

500

Is the sublimation of dry ice into carbon dioxide an example of a physical or chemical change?

A physical change, it's a phase change

Acids and Bases

100

The scale used to measure how acidic or basic something is is called what?

pH scale

200

Is sodium hydroxide (pH 14) an acid or a base?

Base

300

Acids have a pH of ________ to __________ and bases have a pH of _________ to _________.

Acids: 0-6.9 

Bases: 7.1 - 14

400

If a solution has more hydrogen than hydroxide ions, will it be an acid or a base?

Acid

500

If you have a swimming pool that has a pH of 6.8 and the desired pH is 7.5, what will have to be added to the pool? 

a base 

Law of Conservation of Mass

100

Is this equation balanced?: 

2Fe + 3Cl₂ ---> 2FeCl₃

Yes

200

The mass of your reactants is 25 grams. What will the mass of the products be?

25 grams

300

If 12 grams of Nitrogen react with 15 grams of Hydrogen, what is the total mass of the product?  

27 grams 

400

In a chemical reaction, 50 grams of Chlorine was used to produce 95 grams of Sodium Chloride. How much Sodium was used? 

45 grams 

500

Balance the following equation: 

____C₄H₆O₃ + ____H₂O --> ____C₂H₄O₂

 C₄H₆O₃ + H₂O --> 2 C₂H₄O₂

Identifying Reactions

100

Every combustion reaction has to have which 3 elements? 

Hydrogen, Carbon, and Oxygen 

200

What are the products of all combustion reactions?

CO₂ and H₂O (and explosion) 

300

What are the products of all neutralization reactions? 

Salt and water 

400

What type of reaction is this: 

2 MgI₂ + Mn(SO₃)₂ ---> 2 MgSO₃ + MnI₄

Double displacement 

500

In a double displacement reaction, which ions in the compounds switch? 

The cations (positive ions) 

Random Science

100

True or False: 

Hydrochloric Acid (stomach acid) is strong enough to dissolve razor blades

True

200

True or False: 

Humans and giraffes have the same number of neck vertebrae 

True! Humans and giraffes both have 7 vertebrae in the neck 

300

Does sound travel faster in air or water? 

Water

400

How many hearts does an octopus have? 

3 

500

What is the world's tallest grass? 

Bamboo