SCIENCE MIDTERM

Question 1

A mixture that features distinct components that can easily be seen and sorted.

Answer 1

Heterogeneous Mixture

Question 2

A mixture with components that are difficult to see and are spread out uniformly throughout.

Answer 2

Homogeneous Mixture

Question 3

A mixture containing small, undissolved particles that do not separate or settle out if the mixture is undisturbed.

Answer 3

Colloid

Question 4

A mixture with particles that can be seen and easily separated by settling filtration.

Answer 4

Suspension

Question 5

A mixture of a solvent and one or more solutes.

Answer 5

Solution

Question 6

In general, __________ the temperature of the solvent increases the solubility of a solid solute.

Answer 6

Increasing

Question 7

If a cup of tea is left to sit somewhere for a bit of time, what will happen to it’s concentration?

Answer 7

The tea’s concentration will become higher and it will become stronger, because the water evaporates.

Question 8

A friend is making some vegetable soup. He adds some salt to the simmering broth. The salt dissolves , and your friend says the broth’s saltiness is just right. After two more hours of cooking on the stove top, the broth is way too salty. What happened?

Answer 8

concentration. The salts concentration became more because some of the water evaporated.

Question 9

How can the properties of mixtures and solutions be used to classify them?

Answer 9

it can be used to classify them by their solutes, and the suspension. or solubility

Question 10

The measure of how much solute with dissolve in a solvent

Answer 10

Solubility

Question 11

Which is NOT an example of a characteristic physical property?

Answer 11

Burning

Question 12

A change in matter that produces one or more new substances

Answer 12

Chemical Change

Question 13

Chemical Changes Occur when..

Answer 13

bonds are broken and/or formed between molecules or atoms

Question 14

Changes in ________ and _________ are both signs that a chemical reaction has occurred. (Pick 2)

Answer 14

Energy and Mass

Question 15

The only way to be CERTAIN that a chemical reaction has taken place is …

Answer 15

If one or more new substances were created

Question 16

A reaction where the energy released as the products form is greater than the energy required to break the bonds of the reactants.

Answer 16

Exothermic Reaction

Question 17

A reaction where more energy is required to break the bonds of the reactants than is released by the formation of products.

Answer 17

Endothermic Reaction

Question 18

How would you make a chemical reaction happen faster?

Answer 18

INCREASING the temperature

Question 19

Chemical changes are often represented by equations. Physical changes are not represented by equations. Why?

Answer 19

because the change is only physically, not chemically meaning only the visual changed not the substance itself.

Question 20

increasing surface area generally _________ speed of chemical reactions

Answer 20

increases

Question 21

Which three things do chemical equations convey?

Answer 21

The formulas and symbols of the substances used. The reactants and products used in the equation. The proportion in which substances react and produce new substances. The physical state of the substance.

Question 22

2. A chemical formula combines the symbols of different elements to represent ___________.

Answer 22

Molecules

Question 23

Structure a chemical equation. (you do NOT have to use actual elements).

Answer 23

FL3O2 yeilds; CO2H2O

Question 24

Briefly describe the law of conservation of mass. (2-3 sentences

Answer 24

matter is neither created nor destroyed

Question 25

When two or more elements or compounds combine to make a more complex substance.

Answer 25

Synthesis Reaction

Question 26

When one element replaces another element in a compound, or if two elements in different compounds trade places.

Answer 26

Replacement Reaction

Question 27

A reaction which the compounds break down into smaller products.

Answer 27

decomposition reaction.

Question 28

Record the names and formulas of the reactants and products of methane combustion.

Answer 28

reactants; C4, O2, to products; CO2, H20

Question 29

Describe some differences between closed and open systems.

Answer 29

closed sytems are where gases produce chemical reactions, contrary to an open system, where they have an endless supply, and are not contained, or grown by gas

Question 30

Chemicals and resources made by humans are called

Answer 30

Synthetic Materials

Question 31

Anything naturally occurring in the environment that humans use…

Answer 31

Natural resource

Question 32

Long chains of molecules that are made up of repeating units called monomer

Answer 32

Polymers

Question 33

The most common synthetic polymers are…

Answer 33

Plastic

Question 34

List 2 synthetic fibers we talked about in the slides.

Answer 34

Polyester, Spandex.

Question 35

Synthetic food products include..

Answer 35

Preservatives, food colorings etc.

Question 36

Why are synthetic medicines so important?

Answer 36

They are cheaper and easier to make. Safer for example the synthisizatoin of poison from a plant, to heal people with heart problems. This can help more people as well.

Question 37

What are two resources that scientists have been exploring to create synthetic fuels?

Answer 37

Animal oils, and plants.

Question 38

A website publishes an article arguing that synthetic materials do not benefit society because they are created in a lab. Do you think the website is a reliable source? Explain.

Answer 38

It isn’t reliable. You have to acknowledge that synthetic products have benefited
many people, even if the products also carry risks.

Question 39

How can a model be used to identify the components of a chemical reaction?

Answer 39

The three main parts of a chemical reaction are reactants, arrows, and products. Reactants: During a reaction, these compounds or elements combine and undergo some chemical changes. Arrow: In other words, this indicates the formation of products from the reactant, as well as separating the reactant and product.

Question 40

How does the production and use of synthetic materials affect society?

Answer 40

Synthetic textiles affect the environment and climate throughout their lifecycle through resource use, and the emission of greenhouse gasses and pollutants. In addition, between 200 000 and 500 000 tonnes of microplastics from textiles enter the marine environment each year.
Clothing that contains synthetic materials such as polyester and nylon contributes to microplastic pollution, which can end up in the ocean and the seafood that humans eat,