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3 years ago

A cast fossil is formed when

Chemistry

1 answer:

Liono4ka [1.6K]3 years ago

8 0

The answer is D)
when the remains of a living thing are preserved and turned into rock

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Fluorite is..

denpristay [2]

Fluorite is harder than gypsum but softer than apatite. Thus, the correct option is B.

<h3>What is the hardness of any element?</h3>

The hardness of any element may be defined as the capability of a material to oppose the process of deformation and remains in actual shape precisely.

According to the table of hardness scales by Mohs, the increasing order of given hardness of given elements is as follows:

Gypsum < Fluorite < Apatite.

Therefore, Fluorite is harder than gypsum but softer than apatite. Thus, the correct option is B.

To learn more about the Hardness of elements, refer to the link:

brainly.com/question/23721736

#SPJ1

5 0

1 year ago

What four factors influence the rate of a homogeneous reaction.

Anika [276]

1) concentration or partial pressure of species
involved. 2) temperature • 3) presence of catalyst
4) nature of reactants.

5 0

2 years ago

A certain mass of nitrogen gas occupies a volume of 7.56 L at a pressure of 5.08 atm. At what pressure will the volume of this s

faust18 [17]

Answer:

P₂ = 3.86 atm .

Explanation:

We assume that during this change , the temperature of the gas remains constant .

So the gas will obey Boyle's law .

P₁ V₁ = P₂V₂

5.08 x 7.56 = P₂ x 9.94

P₂ = 3.86 atm .

8 0

3 years ago

The following information was recorded by a student team working to prepare nickel sulfate. Plan: Prepare NiSO4 by reacting NiO

mixas84 [53]

Answer:

The options e and d are correct.

Explanation:

Mass of NiO = 7.5 g

Moles of NiO = $\frac{7.5 g}{74.69 g/mol}=0.10 mol$

Moles of sulfuric acid = n

Volume of sulfuric acid ,V= 50 mL = 0.050 L

Molarity of sulfuric acid ,M = 6 mol/L

$n=M\time V=6mol/L\times 0.050 L =0.3 mol$

$NiO + H_2SO_4\rightarrow NiSO_4 + H_2O$

According to reaction, 1 mole of NiO reacts with 1 mole of sulfuric acid.

Then 0.10 moles of NiO reacts with :

$\frac{1}{1}\times 0.10 mol/=0.10 mol$ of sulfuric acid.

As we can see that sulfuric acid is in excess amount, so the amount of the product will depend upon amount of NiO.

According to reaction, 1 mole of NiO gives with 1 mole of $NiSO_4$ .

Then 0.10 moles of NiO wil give :

$\frac{1}{1}\times 0.10 mol/=0.10 mol$ of $NiSO_4$ .

Molar mass of $NiSO_4$ = 154.75 g/mol

Mass of 0.10 moles of $NiSO_4$ :

= 154.75 g/mol × 0.10 mol = 15.475 g

Theoretical mass of $NiSO_4$ = 15.475 g

Experimental yield of $NiSO_4$ = 17.4 g

Percentage yield :

$\Yield=\frac{\text{Experimental mass}}{\text{Theoretical mass}}\times 100$

Percentage yield of $NiSO_4$ :

$\Yield=\frac{17.4}{15.475 g}\times 100=112\%$

Moles of $NiSO_4.6H_2O$ = 262.85 g/mol × 0.10 mol = 26.285 g

Experimental yield of $NiSO_4.6H_2O$ = 17.4 g

Percentage yield of $NiSO_4.6H_2O$ :

$\Yield=\frac{17.4}{26.285 g}\times 100=66.2\%$

3 0

3 years ago

Which condition is indicated by nervous tension, mood swings, headaches, bloating, and irritability?

butalik [34]

The best and most correct answer among the choices provided by your question is the third choice or letter C.

Premenstrual syndrome (PMS) has a wide variety of symptoms, including mood swings, tender breasts, food cravings, fatigue, irritability and depression. It's estimated that as many as 3 of every 4 menstruating women have experienced some form of premenstrual syndrome. Symptoms tend to recur in a predictable pattern.

I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!

4 0

3 years ago