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Romashka [77]
3 years ago
5

All elements are pure substances. True False

Chemistry
1 answer:
oee [108]3 years ago
5 0
It can be a compound or a single element. An element is a pure substance that cannot be separated into simpler substances by chemical or physical means. There are about 117 elements, but carbon, hydrogen, nitrogen and oxygen are only a few that make up the largest portion of Earth.
hopefully that helps
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A spring toy is moving down steps, What happens to the energy of the toy?
tamaranim1 [39]
When the toy is falling down the steps some of the Kinetic energy is changing to potential energy. As it is still falling some of the potential energy changes to kinetic energy.


Hope this helps
7 0
3 years ago
How many grams of h2 are needed to produce 10.78 g of nh3?
balu736 [363]
Ammonia is formed by a reaction between hydrogen and nitrogen as shown by the equation below.
N2(g) + 3H2(g) = 2NH3(g)
1 mole of ammonia contains 17 g
Therefore 10.78 g of ammonia are equivalent to 10.78/17 = 0.6341 moles
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6 0
3 years ago
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ANEK [815]
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3 0
3 years ago
Which of the following processes would you predict to have an increase in entropy?
Anna [14]
C. Melting ice. 
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6 0
3 years ago
Can somebody help me please? it’s urgent
Anettt [7]

Answers:

See attached table

Explanation:

The isotope symbol will have the mass number and chemical symbol.  The atomic number will be equal to the number of protons because the atomic number is the number of protons in an atom.  The electrons will be equal to the protons because the atom is neutral.  The neutrons can be found by subtracting the number of protons from the mass number.  The mass number can be found by adding the protons and neutrons.  It is also in the name of the isotope.

4 0
3 years ago
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