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fgiga [73]
3 years ago
12

Which geologic time did humans exist

Chemistry
2 answers:
umka2103 [35]3 years ago
4 0

Answer:

B

Explanation:

because its says mesozoic era

Phantasy [73]3 years ago
3 0
Humans exist in the mesozoic era
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Which best describes a compound such as sodium chloride?
gayaneshka [121]

Answer:

check it below

Explanation:

NaCl; Sodium Chloride is an ionic compound formed by sodium and Chlorine.

Ionic bond is very strong, It can't be separated back to sodium and chlorine just by physical change. Chemicals which are more reactive can displace ions, thus seperate it

5 0
3 years ago
A 10 gram sample of iron reacts with oxygen to form 18.2 grams of ferric oxide. How many grams of oxygen reacted?
RoseWind [281]

Answer:

\boxed {\boxed {\sf 8.2 \ grams}}

Explanation:

According to the Law of Conservation of Mass, the mass of the products must equal the mass of the reactants.

  • mass products = mass reactants

In this problem, the reaction is:

iron + oxygen = ferric \ oxygen

  • The reactants are iron and oxygen. We know the mass of the iron sample is 10 grams.
  • The product is ferric oxide. The mass of the ferric oxide sample is 18.2 grams.

10 \ g + oxygen=18.2 \ g

We want to find how many grams of oxygen reacted. We have to get the oxygen by itself. 10 is being added to oxygen. The inverse of addition is subtraction. Subtract 10 from both sides of the equation.

10 \ g - 10 \ g+ oxygen = 18.2 \ g - 10 \ g

oxygen= 18.2 \ g - 10 \ g

oxygen= 8.2 \ g \\

<u>8.2 grams of oxygen </u>reacted with 10 grams of iron to form 18.2 grams of ferric oxide.

8 0
2 years ago
Could volume by displacement be used to determine the volume of a lump of rock salt? Explain would be nice
Readme [11.4K]

Yes it could, but you'd have to set up the process very carefully.
I see two major challenges right away:

1).  Displacement of water would not be a wise method, since rock salt
is soluble (dissolves) in water.  So as soon as you start lowering it into
your graduated cylinder full of water, its volume would immediately start
to decrease.  If you lowered it slowly enough, you might even measure
a volume close to zero, and when you pulled the string back out of the
water, there might be nothing left on the end of it.

So you would have to choose some other fluid besides water ... one in
which rock salt doesn't dissolve.  I don't know right now what that could
be.  You'd have to shop around and find one.

2).  Whatever fluid you did choose, it would also have to be less dense
than rock salt.  If it's more dense, then the rock salt just floats in it, and
never goes all the way under.  If that happens, then you have a tough
time measuring the total volume of the lump.

So the displacement method could perhaps be used, in principle, but
it would not be easy.


5 0
3 years ago
An ax is used to chop wood. The metal part chops through the wood, pushing it apart into two smaller sections. which simple mach
Sati [7]
The <span>simple machine found on the head of the  ax is </span>Wedge. A wedge is an inclined plane that can be moved. When an ax is used to split wood, the ax handle exerts a force on the blade of the axe, which is the wedge. That force pushes the wedge down into the wood. The wedge in turn exerts an output force splitting the wood in two. 
3 0
3 years ago
Q3. A student wanted to make blue copper sulfate crystals from green copper carbonate powder
CaHeK987 [17]

Heat the sulfuric acid solution and adding copper carbonate in it.

<h3>Improvement require in this experiment</h3>

The method could be improved by heating sulfuric acid solution and add copper carbonate into the solution of sulfuric acid. Add the copper carbonate until it is present in excess amount. After that filter the extra amount of copper carbonate so in this way the blue copper sulfate crystals are produced.

Learn more about copper here: brainly.com/question/3157958

5 0
2 years ago
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