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2 years ago

I need help with a questino

Chemistry

2 answers:

kipiarov [429]2 years ago

6 0

Explanation:

What will the question be ?

olga nikolaevna [1]2 years ago

3 0

What is the question please and thank you and why do you need help

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In the background information, it was stated that CaF2 has solubility, at room temperature, of 0.00160 g per 100 g of water. How

____ [38]

Answer:

2.05*10⁻⁵ moles of CF₂ can dissolve in 100 g of water.

12.82 moles of CaF₂ will dissolve in exactly 1.00 L of solution

Explanation:

First, by definition of solubility, in 100 g of water there are 0.0016 g of CaF₂. So, to know how many moles are 0.0016 g, you must know the molar mass of the compound. For that you know:

Ca: 40 g/mole
F: 19 g/mole

So the molar mass of CaF₂ is:

CaF₂= 40 g/mole + 2*19 g/mole= 78 g/mole

Now you can apply the following rule of three: if there are 78 grams of CaF₂ in 1 mole, in 0.0016 grams of the compound how many moles are there?

$moles=\frac{0.0016 grams*1 mole}{78 grams}$

moles=2.05*10⁻⁵

2.05*10⁻⁵ moles of CF₂ can dissolve in 100 g of water.

Now, to answer the following question, you can apply the following rule of three: if by definition of density in 1 mL there is 1 g of CaF₂, in 1000 mL (where 1L = 1000mL) how much mass of the compound is there?

$mass of CaF_{2}=\frac{1000 mL*1g}{1mL}$

mass of CaF₂= 1000 g

Now you can apply the following rule of three: if there are 78 grams of CaF₂ in 1 mole, in 1000 grams of the compound how many moles are there?

$moles=\frac{1000 grams*1 mole}{78 grams}$

moles=12.82

12.82 moles of CaF₂ will dissolve in exactly 1.00 L of solution

5 0

2 years ago

On average, Earth’s crust contains about 8.1% aluminum by mass. If a standard 12-ounce soft drink can contains approximately 15

MrMuchimi

Answer:

5400 cans

Explanation:

First we convert the total weight, 1 ton, to grams:

$1ton=1x10^{6}g$

Now we need to know the mass of aluminum:

$m_{Al}=\frac{10^{6}*8.1}{100} =81000g$

Now we make the relation between the mass of aluminum in 1 ton of the earth's crust and the mass of aluminum per can:

$n=\frac{81000g}{15g/can} =5400cans$

8 0

3 years ago

Both __________ and __________ can be classified as pure substances because they have distinct properties and composition.

musickatia [10]

Answer:

Both elements and compounds can be classifies as pure substances because they have distinct properties and composition.

Explanation:

Elements and compounds are considered as pure substances because both are always formed form are have same kind of atoms.

For example,

Carbon dioxide is compound. It always consist of one carbon atom and two oxygen atoms.

Water is compound it always have same kind of atoms two hydrogen and one oxygen that's why compounds are considered as pure substances.

Same is the case with elements. For example,

Hydrogen is element and it always consist of H atoms.

Iron is another element and it always have iron atoms.

So elements and compounds are always consist of same substances that's why they are considered as pure.

4 0

3 years ago

Will mark as Brainliest.

stealth61 [152]

The answer you are looking for is A. If you need me to show you how I got the answer let me know. :)

3 0

2 years ago

I need help with B and C

lakkis [162]

B) Mg is the alkaline earth metal w/12 protons so following the periodic table to the halogen in the same period is

Cl: Chlorine

C) The Neutral noble has w/ 18 electrons is argon so the metal in the same row is

Na: Sodium

8 0

3 years ago