Unit 6 Chemistry Exam Practice

Matter that keeps its own shape. The particles are very tightly packed together. Solids are the only state of matter with a fixed volume (never changing).

SOLID:

States of Matter

LIQUID:

Matter that takes the shape of the container it's in starting from the bottom up. The particles are a little farther apart allowing them to move.

GAS:

Matter that spreads out as far as it can to take up all the space it's in. The particles are really far apart to allow them to move quickly

Multiple Choice

What happens to liquid water when heat is removed from it?

• it melts

• it evaporates

• it freezes

• nothing

Multiple Choice

A student leaves a cup of water outside. When they come back the next day, most of the water is gone. What happened to the water?

• it melted

• it evaporated

• it froze

• it shrank

Reorder

Put the following in order from lowest amount of energy to highest amount of energy. ​ ​

• Solid
• Liquid
• Gas

1

2

3

• 1
• 2
• 3

Enthalpy, Exothermic, and Endothermic Reactions

What is that lovely potential energy diagram I see to the right?

Multiple Choice

Which reaction type is this?

• Exothermic

• Endothermic

Multiple Choice

Which reaction type is this?

• Exothermic

• Endothermic

Multiple Choice

Which reaction type is this?

• Exothermic

• Endothermic

Multiple Choice

Which reaction type is this?

• Exothermic

• Endothermic

Multiple Choice

Which reaction type is this?

• Exothermic

• Endothermic

Multiple Choice

Which reaction type is this?

• Exothermic

• Endothermic

Multiple Choice

Which reaction is an endothermic reaction

• A

• B

• C

• D

Multiple Choice

Which reaction is an exothermic reaction

• A

• B

• C

• D

Multiple Choice

A student lights a match. Endothermic or exothermic?

• exothermic

• endothermic

Multiple Choice

Tiani throws her dough in the oven to bake bread. Endothermic or exothermic?

• exothermic

• endothermic

Multiple Choice

A puddle is evaporating in the sunlight. Endothermic or exothermic?

• exothermic

• endothermic

Earth's Layers

Lets start with the CRUST

The Crust

• The crust is the outermost layer and the thinnest

  There are two types of crust: continental and oceanic.

• Both crusts are made mainly of the elements oxygen, silicon, and aluminum.

The Mantle

• The layer of the Earth between the crust and the core.

• The mantle is much thicker than the crust and contains most of the Earth’s mass

• The mantle has more magnesium and less aluminum and silicon than the crust, making it much more dense

The Mantle Has 2 Main Parts

• The Lithosphere: Made up of two parts- the crust and the rigid upper part of the mantle. This is where tectonic plates are found

• The Asthenosphere: Plastic / Silly putty like part of the mantle that the lithosphere sits on

• The movement of the asthenosphere moves tectonic plates

The Core

• The Outer Core: The liquid layer of the Earth’s core that lies beneath the mantle and surrounds the inner core.

  
  

  
  

• The Inner Core: The solid, dense center of our planet that extends from the bottom of the outer core to the center of the Earth. (3,964 miles beneath the surface)

  
  

  
  

Multiple Choice

True or False. The mantle is hotter than the crust.

• True

• False

Earth's Core

Both the inner and outer core are made up of mostly iron and a little bit of nickel. The inner core is solid, while the outer core is liquid. This liquid flowing deep down below us is what produces Earth's electromagnetic current. And, it's pretty hot in the core - about as hot as the surface of the sun!

Earth's Mantle

The mantle is the thickest layer of Earth, making up about 85% of Earth's volume. The lower mantle is pretty solid stuff, while the upper mantle moves around like silly putty. This movement of rock without breaking is called plasticity, and the liquid part of the mantle is referred to as the asthenosphere.

Lithosphere

On top of the asthenosphere is the lithosphere, which also contains the entire crust. The slow-moving convection currents in the asthenosphere move the tectonic plates of the lithosphere around like ice on a pond, causing earthquakes and volcanoes on the surface. Though the continental crust is much thicker than the oceanic crust, it's made of material that is far less dense. This means that the continental crust 'floats' higher on the liquid mantle below than does the heavier oceanic crust that sinks down like a loaded cargo ship.

Multiple Choice

How does the mantle differ from the crust?

• The mantle is the thickest layer of Earth, while the crust is the thinnest.

• The mantle flows with convection currents, while the crust consists primarily of silicate rocks.

• The mantle is the least stable layer of Earth, while the crust is the most seismically active.

• The mantle consists mostly of lava, while the crust consists mostly of iron.

Multiple Choice

What is the cause of earthquakes, volcanoes, and mountains on Earth?

• Movements in the outer core.

• Convection currents in the mantle.

• Convection currents in the crust.

• Sinking of the oceanic crust.

Multiple Choice

Why is the inner core solid?

• Because it is under too much pressure to melt.

• Because it consists mostly of silicon.

• Because it is very hot.

• Because of plasticity.

Multiple Choice

How does the inner core differ from the outer core?

• The inner core is solid, while the outer core is liquid.

• The inner core is made of iron, while the outer core is made of lithium.

• The inner core is characterized by plasticity, while the outer core's key trait is thermal activity.

• The inner core is very cold, while the outer core is very hot.

Multiple Choice

This is considered as the fastest kind of seismic waves.

• Love waves

• Body waves

• Primary waves

• Secondary waves

Multiple Choice

In what order do the three types of seismic waves arrive at a seismograph?

• S wave, P wave, Surface wave
• Surface wave, P wave and S wave
• P wave, S wave and Surface wave
• P wave, Surface wave and S wave

What are we doing today?

In the warm up question, you thought about a pot of water absorbing energy from the stove. We are going to try to calculate EXACTLY how much energy it absorbed.

First thing we need to know is Specific Heat

• Physical Property of a substance

• Ex: Specific heat of water = 4.18 J/°C g

• If we KNOW the specific heat, we can use it to calcuate the total energy transfered in a system 

Next week need the full equation

q= heat

m = mass

C = Specific Heat

ΔT = Change in Temperature

Multiple Choice

What units are used to measure mass?

• grams

• Joules

• °C

• ml

Multiple Choice

What units are used to measure Temperature?

• grams

• ml

• Joules

• °C

Multiple Choice

I just said this today: What units are used to measure HEAT?

• grams

• Joules

• ml

• °C

Multiple Choice

ΔT = Change in Temperature. How would you calculate the change in temperature?

• Final temperature minus starting temperature

• Starting temperature minus final temperature

Multiple Choice

250g of water (specific heat of 4.184 J/g^oC) is heated from 20^oC to 46^oC.

What is the change in temperature?

• 26^oC

• -26^oC

• 250g

• 66^oC

Multiple Choice

250g of water (specific heat of 4.18 J/g^oC) is heated from 20^oC to 46^oC.

How would you calculate the total heat absorbed by the water?

• 250g x 4.18J/g^oC x 26^oC

• 46^oC - 20^oC

• 250 + 4.18 + 26

Multiple Choice

SOLVE IT: 250g of water (specific heat of 4.18 J/g^oC) is heated from 20^oC to 46^oC.

How much heat did the water absorb?

• 27,170 J

• 20,900 J

• 48,070 J

Open Ended

Calculate the amount of heat needed to raise the temperature of 15g of copper from 25^oC to 60^oC if copper has a specific heat of 0.386 J/g^oC

Open Ended

How much energy is required to raise the temperature of 675g of aluminum from 15^oC to 35^oC. (Specific Heat of aluminum is 0.902 J/g^oC)

Open Ended

The temperature of a piece of Metal X (specific heat of 0.724 J/g°C) with a mass of 95.4 g increases from 25.0°C to

48.0°C. How much heat did it take?

Open Ended

How much heat is added to 3.4 g of olive oil at 21°C if the temperature increases to 85°C? The specific heat of olive oil is 1.97 J/g°C

Specific Heat

​7e. analyze and interpret the concept of specific heat data to justify the selection of a material for a practical application (e.g., insulators and cooking vessels)

Specific Heat

What is it?

The amount of heat required to raise the temperature of the unit mass of a given substance by a given amount (usually one degree).

Lower specific heat capacity
requires a smaller amount of heat energy to raise its temperature
faster to warm up or cool down
ex - most metals

​​Conductors

Higher specific heat capacity
requires a larger amount of heat energy to raise its temperature
slower to warm up or cool down
ex - plastic and wood

​​Insulators

Multiple Choice

Copper, Stainless Steel, Carbon Steel, and Zinc were all heated using 10,000 JOULES of thermal energy.  What material would be have the LARGEST change in temperature?

• Stainless Steel
• Zinc
• Copper
• Carbon Steel

Multiple Choice

Copper, Stainless Steel, Carbon Steel, and Zinc were all heated using 10,000 JOULES of thermal energy.  Based on the chart, which material would have the SMALLEST temperature change?

• Stainless Steel (AISI 304)
• Chromium Steel
• Carbon Steel
• Aluminum

Multiple Choice

There are 2 pans of water, one has 100 mL in it and one has 1000mL. You add 4000 joules of energy,  which one has the bigger change in temperature?

• The 1000 mL pan has the bigger change in temperature.
• The 100 mL pan has the bigger change in temperature.
• Both pans have the same change in temperature.
• The temperature change cannot be determined without knowing the specific heat capacity.

Multiple Choice

Which of the following would be the best insulator?

• Gold
• Copper
• Aluminum
• Silver

Multiple Choice

Which of the following materials, all at 25°C, can absorb the most heat while having the smallest temperature change?

• H2O(l)
• O2(g)
• Fe(s)
• Cu(s)

Convection Currents in the Mantle

By Holli McClelland

Multiple Choice

What is the heat source for convection in the mantle?

• the Crust
• the Mantle
• the Core

Multiple Choice

What is the cooling source for convection in the mantle?

• the Crust
• the Mantle
• the Core

Multiple Choice

 Where do convection currents happen in the model we are studying?

• the Crust
• the Mantle
• the Core

Multiple Choice

When molten  material is heated in the mantle it becomes

• more dense
• less dense 

Multiple Choice

When molten  material is cooled in the mantle it becomes

• more dense
• less dense 

Multiple Choice

When molten  material is heated in the mantle the molecules

• expand (spread out)
• condense (shrink together) 
• stay the same

Multiple Choice

When molten  material is cooled in the mantle the molecules

• expand (spread out)
• condense (shrink together) 
• stay the same

Multiple Choice

Molecules that are more dense than the surrounding particles will...

• rise up
• sink down
• stay put

Multiple Choice

Molecules that are less dense than the surrounding particles will...

• rise up
• sink down
• stay put

Multiple Choice

How does heat move?

• from a warmer to a cooler object

• from a cooler to a warmer object

• toward a hot object

• away from a cold object

URBAN HEAT ISLANDS

How do humans & our cities affect Earth’s climate?

Why is it hotter in cities during the summer?

Open Ended

It’s a hot summer day and you’re deciding what to
wear. Which color shirt would you wear and why?

Darker colored objects absorb

MORE heat!

Let’s see how this relates to temperatures in cities!

URBAN HEAT ISLANDS

● City structures, like buildings and roads, absorb the sun’s heat more than natural/rural landscapes such as forests and bodies of water.

● Urban areas become “islands” of higher temp. compared to rural areas.

● In the United States, the heat island effect results in daytime temperatures in urban areas about 1–7°F higher than temperatures in rural areas

URBAN HEAT ISLAND EFFECTS

● Increase the need for electricity to power air conditioning

• Companies that supply electricity rely on fossil fuels & power plants which leads to an increase in air pollution and greenhouse gas emissions

  • Increases ground-level ozone (smog) and acid rain.

  • contributes to global climate change

​What are Mid-Ocean Ridges?

• In different areas of the Ocean floor, the floor showed signs of "seams" like those on a baseball

  • Curve along the the ocean floor

  • Form Mountain ranges

• Mid-ocean Ridges: long chains of mountains that rise up from the ocean floor​

Grade 8 Ohio | Lesion 5.4

How do we Study Mid-Ocean Ridges?

• In the 1990s, scientists used Sonar to map the ridges

  • Sonar uses sound waves to measure the distance to an object

  • Showed them to be the longest mountain range on Earth

Grade 8 Ohio | Lesion 5.4

Where are Mid-Ocean Ridges?

• Maps showed the ridges extend into all oceans

  • Under thousands of meters of water

  • ​The mid-ocean ridges are split by a steep valley

Grade 8 Ohio | Lesion 5.4

​What is Sea-Floor Spreading

• By the 1960s, geologists had begun to learn more about mid-ocean ridges

• Mid-ocean ridges add new material to the ocean floor

• Sea Floor Spreading: the process by which new material is added to the ocean floor by mid-ocean ridges​

  • A mid-ocean ridge forms in the oceanic crust

  • Molten material rises up, cools, and hardens

  • Over time, the strips of rock move outward from the ridge

Grade 8 Ohio | Lesion 5.4

​Evidence for Sea-Floor Spreading: Ocean Material

• In the central ridges, scientists found rocks shaped like pillows

  • This only happens when molten material hardens quickly

Grade 8 Ohio | Lesion 5.4

​Evidence for Sea-Floor Spreading: Magnetic Strips

• As molten material cools and hardens, magnetic material in it aligns with the direction of Earth's poles​ at times of eruption

  • Poles can reverse direction, so the magnetic stripes can indicate when molten material erupted

• Magnetic stripes are mirror images on either side of the ridge

​Evidence for Sea-Floor Spreading: Drilling Samples

• Rock Samples drilled up from the Ocean crust allowed scientists to compare the ages of samples from different locations

  • The farther from the ridge a sample was taken from, the older the rock

Grade 8 Ohio | Lesion 5.4

Multiple Choice

In Sea-floor spreading, new crust is added at a

• Magnetic Stripe

• Hot Spot

• Mid-ocean ridge

• Lava location

​The Process of Subduction

• Subduction: The process by which the ocean floor sinks beneath a deep ocean trench back into the mantle

• As new material on the ocean floor is created and cooled, it's density changes

  • Initially has a low density when hot, and the density increases as it cools

• While new material cools, it can collide with continental crust

  • Older crust is then pushed down towards the mantle​

Grade 8 Ohio | Lesion 5.4

​Subduction and Earth's Ocean

• Subduction and sea-floor spreading work together to change the size and shape of the ocean

  • They work together like a conveyor belt, replacing the ocean floor every 200 million years

• Size of the crust is determined by how fast crust is being created and destroyed in subduction

Grade 8 Ohio | Lesion 5.4

Multiple Choice

In seafloor spreading, molten material rises from the mantle and erupts

• along the edges of all the continents.

• along mid-ocean ridges

• in deep-ocean trenches

• at the north and south poles

Multiple Choice

Old oceanic crust is more dense than new oceanic crust because it is

• Hotter

• Cooler

• Taller

• Shorter

Sea-floor Spreading

9.2 Sea-Floor Spreading

The age of ocean floor rocks is youngest along the mid-ocean ridge and increases with age as you move away from the ridge. This also supports the idea of sea-floor spreading.

9.2 Sea-Floor Spreading