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3 years ago

13

The fossil record provides evidence of past life as well as clues to the past climate, environment, and abiotic factors in an ar

ea. True or false

2 answers:

Tatiana [17]3 years ago

8 0

The answer would be true.

murzikaleks [220]3 years ago

5 0

That is true because fossils can tell many things.

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Please help me due tomorrow

Dvinal [7]

G
A
C
I
F
D
E
B
J

Explanation:

this are answers

6 0

2 years ago

in order to find the molar mass of an unknown compound, a research scientist prepared a solution of 0.930 g of an unknown in 125

PtichkaEL [24]

Answer:

Molar mass→ 0.930 g / 6.45×10⁻³ mol = 144.15 g/mol

Explanation:

Let's apply the formula for freezing point depression:

ΔT = Kf . m

ΔT = 74.2°C - 73.4°C → 0.8°C

Difference between the freezing T° of pure solvent and freezing T° of solution

Kf = Cryoscopic constant → 5.5°C/m

So, if we replace in the formula

ΔT = Kf . m → ΔT / Kf = m

0.8°C / 5.5 m/°C = m → 0.0516 mol/kg

These are the moles in 1 kg of solvent so let's find out the moles in our mass of solvent which is 0.125 kg

0.0516 mol/kg . 0.125 kg = 6.45×10⁻³ moles. Now we can determine the molar mass:

Molar mass (mol/kg) → 0.930 g / 6.45×10⁻³ mol = 144.15 g/mol

3 0

3 years ago

How is primary selection different from secondary succession?

PIT_PIT [208]

Answer:

Explanation:

Primary and secondary succession occur after both human and natural events that cause drastic change in the makeup of an area. Primary succession occurs in areas where there is no soil and secondary succession occurs in areas where there is soil.

In primary succession, newly exposed or newly formed rock is colonized by living things for the first time. In secondary succession, an area previously occupied by living things is disturbed—disrupted—then recolonized following the disturbance.

Hope this helped :)

-<em>Akito</em>

8 0

2 years ago

Name the separation technique which could be used to separate mud and water without heating

Westkost [7]

Answer:

Decantation

Explanation:

Decantation is a process to separate

mixtures by removing a liquid layer that

is free of a precipitate, or the solids

deposited from a solution. The purpose

may be to obtain a decant (liquid free

from particulates) or to recover the

precipitate.

Decantation relies on gravity to pull

precipitate out of the solution, so there is

always some loss of product, either from

the precipitate not fully falling out of the

solution or from liquid remaining when

separating it from the solid portion.

The Decanter

A piece of glassware called a decanter is

used to perform decantation. There are

several decanter designs. A simple

version is a wine decanter, which has a

wide body and a narrow neck. When

wine is poured, solids stay in the base of

the decanter.

In the case of wine, the solid is usually

potassium bitartrate crystals. For

chemistry separations, a decanter may

have a stopcock or valve to drain the

precipitate or dense liquid, or it may

have a partition to separate fractions.

Use of Alum and filtration process can also be administered for further purification

8 0

3 years ago

D5W is a solution used as an intervenous fluid.It is 5.0% by mass solution of the dextrose (C6H12O6) in water. if the density of

Alona [7]

Answer:

0.29 mol/L

Explanation:

Its density is 1.029 g/ml so in a liter (1000 mL) there is 1029 g of solution, but only 5% is dextrose.

0.05x1029=51.45

So in a liter of D5W solution there is 51.45 g of dextrose.

Dextrose molar mass iss 180.156 g/mol, so in 51.45 g of dextrose there is

51.45/180.156=0.29 mol

In one liter of solution there is 0.29 mol of dextrose, so the molarity of such solution is 0.29 mol/L.

6 0

3 years ago