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3 years ago

How do the first ionization energies of main group elements vary across a period and down a group?

1 answer:

meriva3 years ago

8 0

They increase across each period, decrease down a group. As you go across a period the number of protons and increases. The positive nucleus then has a stronger attractive force on the electrons so it takes a larger amount of energy to remove an electron. As you go down a group the atoms are larger so the attractive force is weaker and it takes less energy to remove an electron.

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What is the difference between soluble and insoluble

klemol [59]

Soluble means it can be dissolved

Insoluble means it can't be dissolved

5 0

2 years ago

I NEED HELP PLEASE !!!!!

Jobisdone [24]

Answer: My opinion is the second one because a lot of humans uses technology and technilogy replaces a lot of stuff.

Explanation:

3 0

2 years ago

Read 2 more answers

Iron is biologically important in the transport of oxygen by red blood cells from the lungs to the various organs of the body. I

Aneli [31]

Answer : The number of iron atoms present in each red blood cell are, $1.077\times 10^9$

Explanation :

First we have to calculate the moles of iron.

$\text{Moles of iron}=\frac{\text{Mass of iron}}{\text{Molar mass of iron}}=\frac{2.90g}{55.85g/mole}=0.0519moles$

Now we have to calculate the number of iron atoms.

As, 1 mole of iron contains $6.022\times 10^{23}$ number of iron atoms

So, 0.0519 mole of iron contains $0.0519\times 6.022\times 10^{23}=3.125\times 10^{22}$ number of iron atoms

Now we have to calculate the number of iron atoms are present in each red blood cell.

Number of iron atoms are present in each red blood cell = $\frac{\text{Number of iron atoms}}{\text{Total number of red blood cells}}$

Number of iron atoms are present in each red blood cell = $\frac{3.125\times 10^{22}}{2.90\times 10^{13}}$

Number of iron atoms are present in each red blood cell = $1.077\times 10^9$

Therefore, the number of iron atoms present in each red blood cell are, $1.077\times 10^9$

6 0

2 years ago

Using the following equation: 3H2SO4+ 2Fe -> Fe2(SO4)3+ 3H2

Mariana [72]

Answer:

H₂SO₄

Explanation:

Given data:

Number of moles of H₂SO₄ = 15 mol

Number of moles of Fe = 13 mol

Which reactant is limiting reactant = ?

Solution:

Chemical equation:

3H₂SO₄ + 2Fe → Fe₂(SO₄)₃ + 3H₂

now we will compare the moles reactant with product.

H₂SO₄ : Fe₂(SO₄)₃

3 : 1

15 : 1/3×15 = 5

H₂SO₄ : H₂

3 : 3

15 : 15

Fe : Fe₂(SO₄)₃

2 : 1

13 : 1/2×13 = 6.5

Fe : H₂

2 : 3

13 : 3/2×13 = 19.5

Number of moles of product formed by H₂SO₄ are less thus it will act as limiting reactant.

8 0

3 years ago

At what height above the earth surface will the gravitational acceleration be 5m

slamgirl [31]

Answer: -

The acceleration due to gravity at height r = a = GM/r²

Rearranging

r² = GM /a

= (6.674 x 10⁻¹¹ x 5.972 x 10²⁴ ) / 5

r = 8.917 x 10⁶ m

r = 8917 Km

Now Radius of earth = 6371 Km

So height = 8917 - 6371 = 2546 Km

8 0

2 years ago