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mariarad [96]
3 years ago
15

The following is true about an index fossil:

Chemistry
1 answer:
finlep [7]3 years ago
4 0

Answer:

the 1st and 4th one. index fossils r imprints and also it is individual animals making the print so it is unique

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Calculate the concentration of A bottle of wine contains 12.9% ethanol by volume. The density of ethanol (CH3OH) is 0.789 g/cm e
Delicious77 [7]

Answer:

The mass percentage of the solution is 10.46%.

The molality of the solution is 2.5403 mol/kg.

Explanation:

A bottle of wine contains 12.9% ethanol by volume.

This means that in 100 mL of solution 12.9  L of alcohol is present.

Volume of alcohol = v = 12.9 L

Mass of the ethanol = m

Density of the ethanol ,d= 0.789 g/cm^3=0.789 g/mL

1 cm^3=1 mL

m=d\times v=0.798 g/ml\times 12.9 mL = 10.1781 g

Mass of water = M

Volume of water ,V= 100 mL - 12.9 mL = 87.1 mL

Density of water = D=1.00 g/mL

M=D\times V=1.00 g/ml\times 87.1 mL =87.1 g

Mass percent

(w/w)\%=\frac{m}{m+M}\times 100

\frac{10.1781 g}{10.1781 g+87.1 g}\times 100=10.46\%

Molality :

m=\frac{m}{\text{molar mass of ethanol}\times M(kg)}

M = 87.1 g = 0.0871 kg (1 kg =1000 g)

=\frac{10.1781 g}{46 g/mol\times 0.0871 kg}

m=2.5403 mol/kg

4 0
3 years ago
Which of these is an example of a chemical change?
Lady_Fox [76]
The only one example of a chemical change would be:

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6 0
2 years ago
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If a 0.7 M solution of Ca(OH)2 dissociates completely in water, what is the<br> final [OH-]?
IceJOKER [234]

Answer:

1.40 M [OH⁻]

Explanation:

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When two hydrogen atoms bond with one oxygen Atom to form water what happens to the electrons
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What type of igneous rock is cooled and solidified above ground?
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Hi, I think the rocks that are cooled and solidified above ground are most commonly basalt. 

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