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3 years ago

I NEED HELP!!!!!!!!!!! PLEASEE!!!!!!!!!!!!!!!!!!!!!!!!!!!

Chemistry

1 answer:

olga_2 [115]3 years ago

7 0

Answer:

[Ar]4s²

Explanation:

The electronic configuration of calcium is given as follows;

1s²2s²2p⁶3s²3p⁶4s²

The electronic configuration of argon, Ar is 1s²2s²2p⁶3s²3p⁶

Given, that there is a similarity be tween the electronic configuration of all the shells of the an atoms of argon and an atom calcium, except for the added valence shell electrons in calcium, the electronic configuration of calcium can be represented by the symbol of an atom of argon, followed by the electonic configuration of the valence shell as follows

The electronic configuration of calcium with argon as base = [Ar]4s².

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how many moles of sodium are needed to react with sulfuric acid to produce 3.75 moles of sodium sulfate according to the followi

anastassius [24]

Hello!

You'll need to react 7,5 moles of Sodium with sulfuric acid to produce 3.75 moles of sodium sulfate

First of all, you need to balance the reaction. The balanced reaction is shown below (ensuring that the Law of Conservation of Mass is met on both sides):

2Na + H₂SO₄ → Na₂SO₄ + H₂

Now, all that you have to do is to use molar equivalences in this reaction applying the coefficients to calculate the moles of Sodium that you'll need:

$molesNa=3,75moles Na_{2} SO_4* \frac{2 moles Na}{1 mol Na_{2} SO_4} =7,5 moles Na$

Have a nice day!

5 0

3 years ago

The mass of an electron is 9.11× 10–31 kg. What is the uncertainty in the position of an electron moving at 2.00 × 106 m/s with

Kruka [31]

Just use the Heisenberg Uncertainty principle:

ΔpΔx = h/2*pi 

Δp = the uncertainty in momentum 
Δx = the uncertainty in position 
h = 6.626e-34 J s (plank's constant) 

Hint: 

to calculate Δp use the fact that the uncertainty in the momentum is 1% (0.01) so that 

Δp = mv*(0.01) 

m = mass of electron 
v = velocity of electron 

Solve for Δx 

Δx = h/(2*pi*Δp) 

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6 0

4 years ago

If you react 2.00 g of hydrogen completely using 15.87 g of oxygen to produce water, how much water (in grams) will you have?

leonid [27]

Answer:

The amount (mass) of water we will have is 17.869 grams

Explanation:

The molar mass of hydrogen gas H₂ = 2.016 grams/mole

The molar mass of oxygen gas = 31.999 g/mol

Therefore, 2.00 g of hydrogen will give;

2.00/2.016 = 0.9921 moles of H₂ gas and

15.87 g of O₂ will give;

15.87/31.999 = 0.49595 moles

The reaction is as follows;

2H₂ (g) + O₂ (g) → 2H₂O (l)

Two moles of H₂ react with one mole of O₂ to produce two moles of H₂O

Therefore 0.9921 moles of H₂ will react with 0.9921/2 or 0.49595 moles of O₂ to produce 0.9921 moles of H₂O

From the above we note that all the H₂ and O₂ are completely consumed to form 0.9921 moles of H₂O

Molar mass of H₂O = 18.01528 g/mol

Number of moles = Mass/(Molar mass)

∴ Mass of H₂O = (Molar mass) × (Number of moles)

= 18.01528 g/mol × 0.9921 moles = 17.869 grams

Therefore the amount (mass) of water we will have = 17.869 grams.

8 0

3 years ago

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Temka [501]

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3 years ago

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mixas84 [53]

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