Leaven Ttt Questions

1. Which is represented when liquid water becomes a gas at 100°C?

Density of water

Solubility of water

Boiling point of water

Chemical reactivity of water

Water turns into steam, .. or to water vapor at 100 degrees C, or when water boils.

Water is a liquid. When it freezes it is ice. Ice is solid water. When water gets hot it turns into vapour. We call it steam, and it is a gas.

Explanation

Water turns into steam, .. or to water vapor at 100 degrees C, or when water boils.

2. When heated, mercuric oxide decomposes (separates) to form liquid mercury and oxygen. A scientist heated 10 grams (g) of mercuric oxide and formed 9.3 grams of liquid mercury. How many grams of oxygen were formed?

0.7 g

9.3 g

10.0 g

19.3 g

Definition: Law of Conservation of Mass is a relation stating that in a chemical reaction, the mass of the products equals the mass of the reactants.

Explanation

Definition: Law of Conservation of Mass is a relation stating that in a chemical reaction, the mass of the products equals the mass of the reactants.

3. Which indicates a chemical reaction is occurring?

A substance melting

A substance evaporating

Bubbles forming when two substances are mixed

Temperature remaining the same when two substances are mixed

The formation is gas bubble is an indication of a CHEMICAL REACTION.

Explanation

The formation is gas bubble is an indication of a CHEMICAL REACTION.

4. Which is the best term to describe a chemical reaction that absorbs heat energy?

Catalytic

Exothermic

Endothermic

Extendheat

Endothermic: a reaction or process which absorbs heat from its surroundings." This is sensed or realized in a reduction of temperature.

Endothermic: a reaction or process which absorbs heat from its surroundings.

Explanation

Endothermic: a reaction or process which absorbs heat from its surroundings." This is sensed or realized in a reduction of temperature.

Endothermic: a reaction or process which absorbs heat from its surroundings.

5. Which of these best describes a change that is physical?

Yarn being knitted into a sweater

The engine from a tractor being started

The metal on a bicycle forming rust

Grass capturing the energy from sunlight

Explanation

6. Mr. Savion was playing around with his grandfather's lab equipment, when two solutions are combined, a bright red precipitate is formed. Which is true of the precipitate?

It has a mass greater than the two liquids

It is formed as a result of a chemical reaction.

It has a higher temperature than the two solutions.

It is formed through a change in physical state of one of the solutions.

A precipitate is a solid that forms and is an indication of a chemical reaction when two clear solution/liquids are mixed.

Explanation

7. A scientist placed a sample of lithium into a container of water. The scientist observed the lithium floating and making a buzzing sound as gas bubbles were forming around it. Which conclusion is best supported by this observation?

Water was vaporized.

A chemical change took place.

The lithium was dissolved by the water.

Dissolved gases were released.

The formation is gas bubble is an indication of a CHEMICAL REACTION.

The alkali metals all react violently with water.

Explanation

The formation is gas bubble is an indication of a CHEMICAL REACTION.

8. Nilson and Kimberly discussed examples of the types of changes in matter. In which example is a chemical change taking place?

A piece of metal is cut in half.

An ice cube melts on a counter.

A camper roasts marshmallows over a burning fire.

A baker mixes together flour and sugar to make dough.

Explanation

9. Liquids placed in a beaker will settle in specific layers. Which physical property of matter does this illustrate?

Density

Polarity

Solubility

Malleability

An object's DENSITY is determined by comparing its mass divided by it's volume. If you compare a rock and a cork that are the same size (they have equal volume), which is heavier? The rock is, because it has more mass. The rock is denser than the cork, then, because it has more mass in the same volume.

The same with liquids, the the heavier liquids will go the bottom and the lighter ones will raise to the top.

When have different liquids have different densities (some are less dense than others) and so 'float' on one another, because each liquid has its own weight and density.

Explanation

An object's DENSITY is determined by comparing its mass divided by it's volume. If you compare a rock and a cork that are the same size (they have equal volume), which is heavier? The rock is, because it has more mass. The rock is denser than the cork, then, because it has more mass in the same volume.

The same with liquids, the the heavier liquids will go the bottom and the lighter ones will raise to the top.

10. The process of digestion breaks down proteins into smaller molecules that are used to rebuild other proteins. During digestion, proteins undergo ______________________________.

Cell division.

Nuclear reactions.

Natural selection.

Chemical changes.

Digestion is a CHEMICAL reaction. Complex chemical compounds undergo reactions, and are broken down into elements and simple compounds.

Food’s macronutrients undergo chemical breakdown as they move through the digestive system.

Explanation

Digestion is a CHEMICAL reaction. Complex chemical compounds undergo reactions, and are broken down into elements and simple compounds.

11. Two clear solutions are mixed together in a beaker, Ms. Dava Hunter. Which result would indicate a chemical reaction had occurred between these solutions?

Increase of volume in the beaker

Decrease of volume in the beaker

Increase in temperature of the beaker

Increase in height of the beaker

Exothermic chemical reactions produce heat.

Explanation

Exothermic chemical reactions produce heat.

12. Read the chemical equation. CH4 + 2O2 --------> CO2 + 2H2O + energy What is the best description for this equation?

Energy is absorbed.

Energy is released.

Energy stays the same.

It changes 5 colors

Many chemical reactions release energy in the form of heat, these are EXOTHERMIC reactions."

Explanation

Many chemical reactions release energy in the form of heat, these are EXOTHERMIC reactions."

13. Students performed an investigation on how aluminum cans taken to a recycling center, were able to be reused. They found out an aluminum can under goes which type of changes?

A physical changes because the can is heated and reshaped

A chemical changes because new metal is formed

A physical change because the no changes are made

A chemical change because an old can is changed into a new can

Physical changes involve states of matter and energy. No new substance is created during a physical change, although the matter takes a different form. The size, shape, and color of matter may change. Also, physical changes occur when substances are mixed, but don't chemically react.

Explanation

14. Mr. Clodfealter disobeyed this mom while she was away. He combines baking soda and vinegar in a flask. Which is the most likely reason Mr. Clodfealter should place a balloon over the mouth of the flask before he mixes the two substances?

To prevent any gas formed as a product from escaping during the reaction

To prevent any liquid used as a reactant from escaping during the reaction

To prevent any powder used as a reactant from escaping during the reaction

To prevent any liquid formed as a product from escaping during the reaction

Only gas will could escape from the test tube. Liquids and powders would not escape in to the air.

Explanation

Only gas will could escape from the test tube. Liquids and powders would not escape in to the air.

15. Tamia Washinton finds a block made from an unknown element. Which is the best way to determine which element was used to create the block?

Test the malleability of the block

Determine the mass of the block

Calculate the density of the block

Observe the reaction between the block and a nonmetal

"To determine the density of irregular shaped objects, we use displacement method to calculate the volume of the illregular shaped object. Use the weight scale or balance to find the mass (m) of object. Use this formula to find the density. Density = mass ( m ) / volume ( V )"

Explanation

"To determine the density of irregular shaped objects, we use displacement method to calculate the volume of the illregular shaped object. Use the weight scale or balance to find the mass (m) of object. Use this formula to find the density. Density = mass ( m ) / volume ( V )"

16. P{margin-bottom:0.08in;} Which statement best describes the formation of rust?

Rust results from a physical mixing of iron with water.

Rust forms from a chemical breakdown of old metal.

Rust results from a chemical reaction between iron and water.

Rust forms from a physical change when wind blows against metal.

When iron and oxygen react in the presence of water or moisture, rust (iron oxide) is formed.

Explanation

When iron and oxygen react in the presence of water or moisture, rust (iron oxide) is formed.

17. Austin Shrader and his new girl friend ____________ placed 35 grams of ice into a dry, 200-gram container. The top of the container was attached tightly. When the ice was completely melted, the student massed the container with the liquid water. What mass of liquid water should be in the container?

35 grams

165 grams

200 grams

235 grams

The law of conservation of matter states that matter cannot be destroyed or created

Explanation

18. Serena was explaining to Carrie, that when a scientist performs an experiment, there are many changes that can occur. Which observation should she list as a chemical change?

The equipment was heated before the experiment.

The shape of the substance changed.

The volume of the substance changed.

The substance changed into a new substance.

http://kgortney.pbworks.com/f/chemicalchanges.gif

Chemical changes occur when a substance combines with another to form a new substance, these processes are called chemical reactions.

Explanation

19. Which best describes a solid produced in a solution during a chemical reaction, from Ms. Hunley's experiment?

Acid

Solute

Reactant

Precipitate

"A precipitate is a solid that forms when two liquids are combined. A common example is that of the mixing of two clear solutions."

Explanation

"A precipitate is a solid that forms when two liquids are combined. A common example is that of the mixing of two clear solutions."

20. When two clear solutions are mixed together in equal amounts, a solid bright yellow substance settles out of the solution. Which best describes what has occurred?

A physical change created a new yellow solution.

A chemical change created a new yellow solution.

A physical change created a new yellow precipitate.

A chemical change created a new yellow precipitate.

"A precipitate is a solid that forms when two liquids are combined. A common example is that of the mixing of two clear solutions."

Explanation

"A precipitate is a solid that forms when two liquids are combined. A common example is that of the mixing of two clear solutions."

Leaven Ttt Questions

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