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Which of these changes can occur in a substance as energy of particles decreases?
The substance evaporates (liquid to a gas)
The substance melts (solid to a liquid)
The substance condenses (gas to a liquid)
The substance sublimes (solid to a gas)
During an experiment, a class heated a balloon that had an initial (starting) circumference of 25 cm. The circumference increased to 27 cm. Which is the best conclusion that can be drawn?
The energy of the molecules inside the balloon remained the same
The molecules inside the balloon were escaping outside
The molecules inside the balloon lost energy to the outside
The molecules inside the balloon gained energy from the heat
Emily made a chart that included physical and chemical changes. Which change should be categorized as a chemical change?
a gold bar melted
iron becomes rusty
lake water evaporates
a granite rock is polished
Which statement best describes the characteristics shared by three isotopes of the same element?
They all have the same atomic mass
They all have the same number of protons
They all have the same chemical stability
They all have the same number of neutrons
Copper and Gold have similar reactive properties. On the periodic table of the elements, these elements are most likely to
have the same number of protons
be in the same group
be in the same period
have nearly the same mass
The alkaline earth metal elements are in the same family in the periodic table because they all have
one valence electron
two valence electrons
eight valence electrons
seven valence electrons
Which element is most likely to form an ion with a negative 2 charge?
The Conservation of Matter can be demonstrated by using chemical equations. Which chemical equation demonstrates the conservation of matter?
Cl + 4Na --> 4NaCl
4P + 5HNO3 --> 5NO + 3H3PO4
I2 + 5Cl2 + 6H2O --> 2HIO3 + 10HCl
2Sn + 4NO3 --> SnO2 + 4NO2 + H2O
Which best describes chemical synthesis?
heat being given off as two elements react with each other
two or more elements combining to form a new compound
an amount of acid reacting with an equal amount of base
a compound being broken down into smaller compounds
Students tested the pH of four different solutions using litmus paper and recorded the observations in the data table given.
Which solution is neutral?
Which range of the pH scale would most likely include acid rain?
Which of the following describes a difference between fission and fusion?
Fusion requires energy to form elements and fission does not
Fusion combines energy from reactions and fission does not
Fusion required energy to start reactions and fission does not
Fusion combines smaller nuclei and fission does not
Students were investigating the advantages and disadvantages of nuclear power. Which statement best explains why a society would choose nuclear power despite its disadvantages?
Nuclear power plants produce large amounts of energy with little air pollution
Radioactive waste storage units have become available
Nuclear power plants are less costly to build
Reactor malfunctions leading to environmental contamination are minimal