Science Exam 1 Review

which one is a physical change?

evaporation and sublimation

One cup of water is left outside for two days when it was checked there was only half a cup left. What happened?

evaporation; physical change

Boiling is a chemical change. true or false

false

Brady lit a match and said it was a physical change. true or false

false

melting is a chemical change. true or false

false

Will an object with a density of 0.999 sink or float in water?

float

Baking soda and vinegar are mixed,and immediately there are bubbles and fizzing. What does this show?

formation of a gas

Which of the following is a sign that a chemical reaction has occurred? change in shape, melting, formation of a gas, or dissolving

formation of a gas

What is the production of a precipitate?

formation of solid particles out of a liquid

Which of these would be correct to put at the end of a density answer?

g/ml

Which of the following IS a physical change? Getting a haircut, Rusty metal, sour milk, a compound

getting a hair cut

Which lab tool might you use to measure the volume of a liquid?

graduated cylinder

Helium balloons rise on earth because

helium is less dense than air

A brick sinks in water while a wooden block of the same size floats. This is because the brick has a

higher density than the wooden block

what happens when water freezes?

ice is formed; physical change

A can of Coke will sink in a bowl of water. A can of Diet Coke will float in a bowl of water. What does this tell you about the density of the Diet Coke?

it is smaller than 1

Which of the following properties is a physical property? magnetism, reactivity with oxygen, flammability, non-reactive

magnetism

The density of Prof. Tesfay can be measured using which of these quantities?

mass and volume

Which of the following is NOT a physical property? breaking a window, color, density, or freezing point

breaking a window

A man going camping chops a log to make firewood. Then he burns the firewood to roast his marshmallows.Which of these activities demonstrated a chemical change?

burning the firewood

A half-eaten apple turns brown. How do we know that this is a chemical change?

change in color

what is the definition of physical change?

changes affecting the form of a chemical substance, but not its chemical composition.

If a student is combining two substances and sees bubbles and fizzing, a ______ is probably taking place.

chemical

Is bleaching your hair a physical or chemical change?

chemical

Is burning wood a chemical or physical change?

chemical

Is moldy cheese a chemical or physical change?

chemical

Adding baking soda and vinegar together and it fizzes and creates carbon dioxide is a

chemical change

Discoloration of a coin is a

chemical change

Green bananas turning yellow on their own as they ripen is a

chemical change

Photosynthesis is an example of a

chemical change

The smell your dog makes after eating to much people food is a

chemical change

When elements bond together, this results in a

chemical change

what is burning?

chemical change

what is digestion?

chemical change

What kind of properties can only be observed when a substance changes into a different substance?

chemical properties

what is solubility?

chemical property

A student stirs two liquids together and they turn into a solid. What type of change has happened and why?

chemical, because a new substance was formed

What Brady do to an egg for a chemical change.

cook the egg

Which is a chemical change? freezing fruit juice, slicing a potato, boiling water, or copper metal turning green

copper metal turning green

The following liquids are poured together in a beaker: alcohol (density=0.79), corn syrup (density=1.38), water (density=1.0), and cooking oil (density=0.93). Which of these liquids will sink to the bottom of the beaker?

corn syrup

Which property of matter is determined by dividing its mass by its volume?

density

What is the formula for density?

density = mass / volume

Which of the following IS a chemical change using chalk, water freezing, slicing cheese, digestion

digestion

Someone accidentally dropped a test tube on the floor and it shatters. Is this an example of a chemical change?

No, because the identity of the glass wasn't altered

I have two objects with the same volume but different masses. Which object will be more dense?

The object with more mass.

which one is the definition of chemical property?

a property or characteristic of a substance that is observed during a reaction where the chemical composition of a substance is changed

What is a precipitate?

a solid forms when one liquid is poured into another

Which of these would indicate that a new substance has been formed? a substance changed color, the volume of a substance increased, a solid became a liquid

a substance changed color

which one is a chemical property? odor, combustibility, solubility, or all of the above

all of the above

what is the definition of chemical change?

any change that results in the formation of new substances.

The tool used to measure the mass of a substance or object is a ______________.

balance

An object with which of the following densities will float on water? 0.7 g/cm3, 1.2 g/cm3, 3.5 g/cm3, or 11.4 g/cm3

0.7 g/cm3

What is the density of a liquid that has a mass of 27g and a volume of 30ml?

0.9 g/ml

What is the density of water?

1 g/ml

Veal finds a gold colored rock in a river. It has a mass of 9.65 grams and a volume of 0.5 cm3. What is the density of the rock?

19.3 g/cm3

A student mixes two clear liquids and sees the production of a bright yellow precipitate. How many indications are there of a chemical change?

2

Frank has an eraser. It has a mass of 4g, and a volume of 2cm3. What is its density?

2 g/cm3

A block has a mass of 54g and a volume of 20cm3. What is the density of the block?

2.7 g/cm3

A student mixes two chemicals and sees the production of bubbles, the formation of a precipitate, a change in shape, and heat being produced.How many of these observations indicate a chemical change?

3

Frank has a paper clip. It has a mass of 9g and a volume of 3cm3. What is its density?

3 g/cm3

What is the density of a substance that has a mass of 30g and a volume of 6 liters?

5 g/l

Jack has a rock. The rock has a mass of 14g and a volume of 2cm3. What is the density of the rock?

7 g/cm3

Find the density of a 2 cm x 2 cm x 2 cm cube with a mass of 64 g.

8 g/cm3

A piece of copper has a mass of 89g and a volume of 10 cm3. What would be the density of the copper?

8.9 g/cm3

A student has baking soda, sugar,and vinegar. What should he do if he wants to see a chemical reaction? Stir the baking soda and sugar together and notice the color, Add the sugar to the vinegar and watch it dissolve, Add the baking soda to the vinegar and watch for bubbles

Add the baking soda to the vinegar and watch for bubbles

You know you a chemical reaction has occurred if there is a precipitate. there is a color change, there is a temperature change, All of these answers are evidence.

All of these answers are evidence.

One of the signs of a chemical reaction taking place is: Bubbles are produced, Reactants are not combining, Products are not forming, Color is not changing

Bubbles are produced

Which is a Chemical property? Thermal Conductivity, Density, Malleability, or Flammability

Flammability

A student mixes two clear liquids and the mixture slowly turns orange.Which conclusion can we draw about the clear liquids?

They formed a new substance

A student mixes a white powder with a clear liquid and the liquid turns cloudy white. What can we conclude about the powder and the liquid?

They underwent a physical change

Someone puts a water bottle in the freezer and it turns to ice. Is this an example of a physical change?

Yes, because a new substance was not formed.

Which units of measurement are used for volume?

milliliter

In chemical reactions, the law of conservation of mass is...... disobeyed, not true, obeyed, or used sometime

obeyed

Is hammering wood together to build a house a chemical or physical change?

physical

Is melting butter for popcorn a chemical or physical change?

physical

Someone takes a piece of fabric and cut it up into lots of small pieces. Is this a chemical change or a physical change?

physical

A change in the size, shape, or state of matter.

physical change

Kim puts an ice cube in a beaker and it melts. This is a good example of:

physical change

Using dye to change the color of a shirt green.

physical change

When you break a cracker into pieces it is a

physical change

Which type of change is easier to reverse?

physical change

what is condensing?

physical change

Someone boils water until it evaporates. What kind of change has happened and why?

physical, because a new substance was not formed

A scientist has four different liquids and pours them all into a bottle. The silver liquid sinks to the bottom, the red liquid settles on top of the silver one, and the pink liquid stays at the surface. Which liquid has the smallest density?

pink liquid

Exothermic reactions...

release energy

During a chemical change, a student notices the production of heat. What does this indicate?

release in energy

which one is a chemical change? density, color, or respiration

respiration

Will an object with a density of 1.01 g/cm3 float or sink?

sink

Which of the following is NOT an example of a physical change? crumpled paper, pencil sharpening, shrunken clothing, or sour milk

sour milk

Which of the following is NOT evidence that a new substance has been formed? change in color, production of a gas, or stirring 2 substances together

stirring 2 substances together

density

the degree of compactness of a substance.

At the end of chemical reactions, what is the total mass of the reactants compared to the total mass of the products?

the mass is the same

A student has two 100 mL beakers of different clear liquids, both at room temperature. The student mixes them. Which of these reactions would NOT show a chemical change? The mixture's volume is 200 mL., The mixture turns blue., The mixture heats up.

the mixture's volume is 200 mL.

The Law of Conservation of Mass proves that

the number of atoms in a chemical reaction does not change

Why do ice cubes float in a glass of water?

the water is more dense than the ice cubes

Why do some substances float on water?

they are less dense than water

Matter is never destroyed or created in chemical reactions. true or false

true

True or False: The density of a specific type of material never changes.

true

energy is a chemical property. true or false

true

what stays the same when there is a physical change? density, volume, neither

volume