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2 years ago

Question 14 of 25

2 answers:

5 0

A. Areas within an energy level that are occupied by electrons

There are different energy levels where electrons (probably) are, they are hanging out in the orbitals, or energy levels around the nucleus.

We know the other options are wrong because protons are in the nucleus of an atom, neutrons have a neutral charge, and although B sounds right, A is the more accurate choice

algol132 years ago

3 0

Answer:

describes properties characteristic of no more than two electrons in the vicinity of an atomic nucleus or of a system of nuclei as in a molecule

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How large is the observable universe

Norma-Jean [14]

Here goes the question with no exact answer, lol <3

Scientists tell us that the observable universe is about 90 light years but then I wonder how they calculated that because the universe is immense!

I'm sorry but I can't go deeper into explaining as that's a tough question.

7 0

2 years ago

photoshop1234 [79]

If the element have 39 protons, that means that his atomic number is 39, being Yttrium the element. And, the number of protons is the same of the number of electrons, so, 39 electrons.

6 0

3 years ago

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Trimix 10/50 is a gas mixture that contians 10% oxygen and 50% helium, and the rest is nitrogen. If a tank of trimix 10/50 has a

Marat540 [252]

Answer : The partial pressure of helium is, $1.815\times 10^4KPa$

Solution : Given,

Molar mass of $O_2$ = 32 g/mole

Molar mass of helium = 4 g/mole

Molar mass of $N_2$ = 28 g/mole

Total pressure of gas = $2.07\times 10^4KPa$

As we are given gases in percent, that means 10 g of oxygen gas, 50 g of helium gas and 40 g of nitrogen gas present in 100 g of mixture.

First we have to calculate the moles of oxygen, helium and nitrogen gas.

$\text{Moles of }O_2=\frac{\text{Mass of }O_2}{\text{Molar mass of }O_2}=\frac{10g}{32g/mole}=0.3125moles$

$\text{Moles of }He=\frac{\text{Mass of }He}{\text{Molar mass of }He}=\frac{50g}{4g/mole}=12.5moles$

$\text{Moles of }N_2=\frac{\text{Mass of }N_2}{\text{Molar mass of }N_2}=\frac{40g}{28g/mole}=1.428moles$

Now we have to calculate the total number of moles of gas mixture.

$\text{Total number of moles of gas}=\text{Moles of oxygen gas}+\text{Mole of helium gas}+\text{Moles of nitrogen gas}$

$\text{Total number of moles of gas}=0.3125+12.5+1.428=14.24moles$

Now we have to calculate the moles fraction of helium gas.

$\text{Mole fraction of He gas}=\frac{\text{Moles of He gas}}{\text{Total number of moles of gas}}=\frac{12.5}{14.25}=0.877$

Now we have to calculate the partial pressure of helium.

$p_{He}=X_{He}\times P_T$

where,

$p_{He}$ = partial pressure of helium

$P_T$ = total pressure

$X_{He}$ = mole fraction of helium

Now put all the given values in this formula, we get

$p_{He}=(0.877)\times (2.07\times 10^4KPa)=1.815\times 10^4KPa$

Therefore, the partial pressure of helium is, $1.815\times 10^4KPa$

8 0

3 years ago

A displacement reaction takes place when calcium is placed in a solution of zinc chloride. Which substances will most likely be

Karolina [17]

Hi!

The correct option would be A.

This is because the displacement reaction would take place as follows

Ca + ZnCl2 --> CaCl2 + Zn

A displacement reaction is one in which a substitution occurs, as the more reactive element in the mixture replaces one that is less reactive.

In the electrochemical series, we find Ca higher than Zn, which is indicative of Ca being more reactive, and having the capacity to displace Zn to form a compound.

Option D would be incorrect as no such substitution occurs.

Option B would be incorrect because again, there is no substitution occurring, and also because two metals alone (Ca and Zn in our case) can never react to form a compound.

Option C would be incorrect because it is not possible because CaCl and ZnCl are forms that are too unstable to exist due to an overall positive charge.

Hope this helps!

5 0

3 years ago

What is the IMA of the 1 st class lever in the graphic given?<br><br> 2<br> 3<br> 0.5

Zina [86]

Answer:

I believe the answer isT 2.

Explanation:

he formula for IMA of a first-class lever is effort-distance/resistance-distance.

6 0

3 years ago

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