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Masja [62]
3 years ago
15

The period 4 alkaline-earth metal has the name_______ . An isotope of this element having 20 neutrons has amass numberof _______

Chemistry
1 answer:
Cerrena [4.2K]3 years ago
6 0

Answer:

The period 4 alkaline-earth metal has the name Calcium. An isotope of this element having 20 neutrons has a mass number of 40.

Explanation:

Looking at the periodic table 4th row for the alkaline-earth metal, we can find Calcium which has an atomic number of 20 (or protons number, or z). The mass number is given by the sum of protons and neutrons. If the number of protons in this case is 20 and the number of neutrons is also 20, the mass number A = 40.

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3 Na2O(aq) + 2 Al(NO3)3(aq) ----> _ Compound A + _ Compound B
Olin [163]
3Na2O(at) + 2Al(NO3)3(aq) —> 6NaNO3(aq) + Al2O3(s)

This is a double replacement reaction and NaNO3 is aqueous because Na is an alkali metal, plus nitrate is in the solution. Both of these are soluble. Al2O3 is not soluble because it does not contain any element that is soluble and is hence the precipitate.

Hope this helped!
7 0
3 years ago
What is the word equation for 2Mg+O2=2 MgO
yarga [219]

Answer:

magnesium + oxygen ----> magnesium oxide

8 0
3 years ago
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The standard free energy of activation of one reaction A is 95.00 kJ mol–1 (22.71 kcal mol–1). The standard free energy of activ
diamong [38]

Answer:

The answer to the questions are as follows

Reaction B is 4426.28 times faster than reaction A

(b) Reaction B is faster.

Explanation:

To solve the question we are meant to compare both reactions to see which one is faster

The values of the given activation energies are as follows

For A

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for  B

Ea = 74.20 kJ mol–1 (17.73 kcal mol–1)

T is the same for both reactions and is equal to 298 k

Concentration of both reaction = 1M

The Arrhenius Law is given by

k = Ae^{\frac{-E_{a} }{RT} }

Where

k = rate constant

Ea = activation energy

R = universal gas constant

T = temperature  (Kelvin )

A = Arrhenius factor

Therefore

For reaction A, the rate constant k₁ is given by k₁ = Ae^{\frac{-95000}{(8.314)(298)} }

And for B the rate constant k₂ is given by k₂ = Ae^{\frac{-74200 }{(8.314)(298)} }

k₁ = A×2.225×10⁻¹⁷

k₂ = A×9.850×10⁻¹⁴

As seen from the above Reaction B is faster than reaction A by (A×9.850×10⁻¹⁴)/(A×2.225×10⁻¹⁷) or 4426.28 times

3 0
3 years ago
What is the molecular geometry around each carbon atom in a saturated hydrocarbon?
Lelu [443]
Answer:
            <span>Molecular geometry around each carbon atom in a saturated hydrocarbon is Tetrahedral.

Explanation:
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7 0
3 years ago
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2. Potassium is a metal with one valence electron. With which other elements does it form bonds? a elements with one electron b.
Anika [276]

Answer:

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Explanation:

6 0
3 years ago
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