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3 years ago

Plz answerrrr I dunnoooo

Chemistry

2 answers:

Hitman42 [59]3 years ago

5 0

The correct answer is around noon as the sun is overhead so the shadow is shortest at this point

aleksley [76]3 years ago

3 0

Midnight is your answer.

plz mark as brainliest. i really need it ;-;.

Just ask if you need more help

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A 15.0-L scuba diving tank contains a helium-oxygen (heliox) mixture made up of 23.0 g of He and 4.14 g of O2 at 298 K. Calculat

EleoNora [17]

Answer: The mole fraction of Helium is 0.978 and that of oxygen gas is 0.022

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For helium:

Given mass of helium = 23 g

Molar mass of helium = 4 g/mol

Putting values in equation 1, we get:

$\text{Moles of helium}=\frac{23g}{4g/mol}=5.75mol$

For oxygen gas:

Given mass of oxygen gas = 4.14 g

Molar mass of oxygen gas = 32 g/mol

Putting values in equation 1, we get:

$\text{Moles of oxygen gas}=\frac{4.14g}{32g/mol}=0.129mol$

Mole fraction of a substance is given by:

$\chi_A=\frac{n_A}{n_A+n_B}$

For helium:

Moles of helium = 5.75 moles

Total moles = [5.75 + 0.129] = 5.879 moles

Putting values in above equation, we get:

$\chi_{(He)}=\frac{5.75}{5.879}=0.978$

For oxygen gas:

Moles of oxygen gas = 0.129 moles

Total moles = [5.75 + 0.129] = 5.879 moles

Putting values in above equation, we get:

$\chi_{(O_2)}=\frac{0.129}{5.879}=0.022$

Hence, the mole fraction of Helium is 0.978 and that of oxygen gas is 0.022

3 0

3 years ago

Identify bohrs model of the atom. His model described the reactivity of an element based on its number of valence electrons.

4vir4ik [10]

E is Bohrs model the dots on the rings represent the valence electrons

6 0

3 years ago

Read 2 more answers

Which of these pairs of elements have the same number of valence electrons?

ElenaW [278]

The correct answer is the second option; sodium (Na) and potassium (K.)
Both sodium and potassium have the same number of valence electrons.

6 0

3 years ago

At what temperature will 2.50 moles of ideal

Sever21 [200]

Answer: 1,218K

Explanation:

7 0

2 years ago

Copper sulfate can crystalize as an anhydrate (no water in the crystal) or as three different hydrates (varying amounts of water

Maurinko [17]

Answer:

Two factors that might have a affect of which copper sulphate mineral will occur at a given location is:

A. Copper sulphate high solubility in water

B. Also it binds nicely with the sediments or the crystal.

Explanation:

As it is mentioned here that copper sulphate can be crystallized as an anhydrate which means that their is no waterin those crystals or can be as of those three different hydrates whose crystal structure varies with the amount of water present in it.

The four forms are also given of the copper sulphate are:

Bonatite
Boothite
Chalcanthite
Chalcocyanite

So, the two factors that might give an affect which type of copper sulphate mineral willoccur at a given location is:

A. The copper sulphate high solubility in water.

B. It binds extremely nicely with the sediments or say to the crystal. It is also regulated by plants.

8 0

2 years ago