can anyone please help with questions my brother gave me?

Question

anonymous · Answer

1.  
Density is the relationship between ____.  (1 point)

    mass and volume
    cubic centimeters and pounds
    weight and volume
    grams and mass

2.  
Which of the following is NOT a possible sign of a chemical change?  (1 point)

    a change in state
    a change in color
    the release of a gas
    the release of energy

3.  
Which of the following is true about an object that floats in water?  (1 point)

    The object is less dense than frozen water.
    The mass of the object is less than that of water.
    The density of the object is less than that of water.
    The volume of the water is greater than the object’s volume.

4.  
Three examples of physical change are ____.  (1 point)

    boiling water, a nail rusting, and a melting candle
    a pond freezing, breaking glass, and a burning candle
    melting ice, mowing the lawn, and carving a statue
    applying lipstick, making lemonade, and baking bread

5.  
Suppose a customer brings a gold bracelet to a jeweler and asks for it to be changed into a gold ring. Which of the following is true?  (1 point)

    The physical property of color will be changed.
    The bracelet will go through a chemical change.
    The composition of the bracelet will change.
    The shape of the gold will change physically.

6.  
Which of the following explains how water causes rocks to weather?  (1 point)

    Water can melt rock material.
    Water freezes in the cracks and expands, causing breaks.
    Water reacts with the rock and produces gases.
    all of the above

7.  
How can you tell that the fireworks exploding during a Fourth of July display do not all contain the same ingredients?  (1 point)

    different colors of explosions
    different shapes of explosions
    different timing of explosions
    all of the above

8.  
Which of the following explains why the chemical products from a reaction have a different mass than the chemicals at the beginning?  (1 point)

    The products are heavier and sink.
    The products are lighter and rise.
    The products are a gas and escape into the air.
    The products are a solid and have more mass.

Fill in the Blank
9.  
The main difference between physical and chemical changes is that _______ changes are not reversible.  (1 point)
Essay

anonymous · Answer

i think this is his homework sheet from last week? please help please

anonymous · Answer

you think you can help?

anonymous · Answer

Try to google it!! Sorry I'm in a quiz! :D

anonymous · Answer

1a2a3c4b???5d6b7a8c9 chem???wrong question

anonymous · Answer

? wrong question

anonymous · Answer

chemicl changes sometimes can be reversed but maybe energitally unfavourable these are called reversible chemical reactions

anonymous · Answer

so it is chemicl changes? for number 9?

anonymous · Answer

maybe ?ask ur bro....

anonymous · Answer

9.  
The main difference between physical and chemical changes is that _______ changes are not reversible.  (1 point)

anonymous · Answer

yes the examiner meant chemical change .......as answer i suppose

anonymous · Answer

ok thanks very much

anonymous · Answer

physical changes can be easily reversed by changing temperature of substance