Substances are____________________________
An unexpected color change, temp change, combustion or burning, when a solid appears & bubbles are examples of
B. chemical change
Will the properties of the two samples likely be the same or different?
A.different; the groups of atoms that make up each sample are different
B.different; there are more groups of atoms in Sample 2
C.same; the groups of atoms in each sample have the same number of atoms
D.same; the groups of atoms in each sample have the same types of atoms
A.different; the groups of atoms that make up each sample are different
Which of the following provides the best evidence that a chemical change is taking place?
A. Ice melting
B.A flame burns on paper
C.Steam rises from the ground
D.A metal object becomes shorter when it is cooled
B.A flame burns on paper
Properties are_____________________________.
Which one is a chemical change?
A student makes a ball-and-stick model of a molecule, as shown below. The black balls represent carbon atoms, and the white balls represent hydrogen atoms.
Based on the model, what is the chemical formula of the molecule?
A.C3H8
B.C3H10
C.3CH
D.3CH8
A.C3H8
What is the law of conservation of mass?
Matter cannot be created or destroyed!
Two or more substances physically combined is called a_________________.
B. mixture
A group of students do an activity with baking soda and vinegar. The steps of the activity are listed below:
1. Pour 100 g of vinegar into a flask.
2. Add 10 g of baking soda to the flask.
3. Observe as the contents of the flask fizz (produce bubbles).
Describe one piece of evidence that a chemical reaction occurs when baking soda is added to vinegar.
The contents of the flask started bubbling ( Fizzing)
Two containers with different volumes hold the same number of particles of the same gas, as shown.
The density of container 2 is ____________ the density of container 1.
A.two times
B.the same as
C.one-half
D.four times
C.one-half
Key concept: Different substances have________________.
B. different properties
Which of the following best describes a mixture?
A.a material that is made up of many molecules
B.a substance that can be changed into another substance
C.a material that contains two or more different substances
D.a substance that has been broken down into its smallest parts
C.a material that contains two or more different substances
Calculate the total mass of all the products of the reaction, including units. Then, provide reasoning to support your answer.
100g + 10g = 110g
Payton mixed two samples together: She analyzed the results and found two ending substances.
One of the ending substances was a white solid. This ending substance is made up of the repeating group of atoms shown above.
Which of the diagrams to the left shows the groups of atoms that make up the samples Serena first mixed together?
A.
B.
C.
D.
a process in which atoms rearrange to form new substances
A starting substance that is part of a chemical reaction.
After the fizzing stops, the students determine that the liquid in the flask has a mass of 105 g. Explain why this is wrong
When you calculate the mass of the vinegar and baking soda it equals to 110g because the weight of the substances do not change.
Mia’s model has an error. What can Caitlin do to correct her model?
A.Erase a hydrogen atom from the reactant molecule that has two hydrogen atoms.
B.Add another hydrogen atom to the product molecule that has one hydrogen atom.
C.Change the reactants to three molecules of one hydrogen atom and one oxygen atom.
D.Change the product to one molecule of four hydrogen atoms and two oxygen atoms.
B.Add another hydrogen atom to the product molecule that has one hydrogen atom.
T or F: Two reactants mixed together always create one product
B. False
A sound technician at a music studio is comparing the sound waves from two instruments.
Which of the following claims is best supported by the diagram?
A.Instrument 1 is louder and higher-pitched than instrument 2
B.Instrument 1 is quieter and higher-pitched than instrument 2
C.Instrument 1 is louder and lower-pitched than instrument 2
D.Instrument 1 is quieter and lower-pitched than instrument 2
A.Instrument 1 is louder and higher-pitched than instrument 2