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3 years ago

What is the total number of electrons in a Mg2+ ion?(1) 10 (3) 14 (2) 12 (4) 24

1 answer:

Citrus2011 [14]3 years ago

5 0

The answer is (1) 10. The protons of Mg atom is 12. So the Mg atom has 12 electrons. The Mg2+ ion has lost two electrons so it has two positive charge. Then the answer is 10 electrons.

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Practice Problem: True Stress and Strain A cylindrical specimen of a metal alloy 49.7 mm long and 9.72 mm in diameter is stresse

amm1812

Answer:

The true stress required = 379 MPa

Explanation:

True Stress is the ratio of the internal resistive force to the instantaneous cross-sectional area of the specimen. True Strain is the natural log to the extended length after which load applied to the original length. The cold working stress – strain curve relation is as follows,

σ(t) = K (ε(t))ⁿ, σ(t) is the true stress, ε(t) is the true strain, K is the strength coefficient and n is the strain hardening exponent

True strain is given by

Epsilon t =㏑ (l/l₀)

Substitute㏑(l/l₀) for ε(t)

σ(t) = K(㏑(l/l₀))ⁿ

Given values l₀ = 49.7mm, l =51.7mm , n =0.2 , σ(t) =379Mpa

379 x 10⁶ = K (㏑(51.7/49.7))^0.2

K = 379 x 10⁶/(㏑(51.7/49.7))^0.2

K = 723.48 MPa

Knowing the constant value would be same as the same material is being used in the second test, we can find out the true stress using the above formula replacing the value of the constant.

σ(t) = K(㏑(l/l₀))ⁿ

l₀ = 49.7mm, l = 51.7mm, n = 0.2, K = 723.48Mpa

σ(t) = 723.48 x 106 x (㏑(51.7/49.7))^0.2

σ(t) = 379 MPa

The true stress necessary to plastically elongate the specimen is 379 MPa.

6 0

3 years ago

Read 2 more answers

How many grams of aluminum is produced when 82.4 grams of aluminum chloride

yKpoI14uk [10]

Answer:

16.6 g of Al are produced in the reaction of 82.4 g of AlCl₃

Explanation:

Let's see the decomposition reaction:

2AlCl₃ → 2Al + 3Cl₂

2 moles of aluminum chloride decompose to 2 moles of solid Al and 3 moles of chlorine gas.

We determine the moles of salt:

82.4 g . 1mol/ 133.34g = 0.618 moles

Ratio is 2:2. 2 moles of salt, can produce 2 moles of Al

Then, 0.618 moles of salt must produce 0.618 moles of Al.

Let's convert the moles to mass → 0.618 mol . 26.98g /mol = 16.6 g

6 0

3 years ago

All the substances listed below are fertilizers that contribute nitrogen to the soil.

kvv77 [185]

Answer:

Ammonia is the richest source of nitrogen on a mass percentage basis because it has 82.35% of nitrogen by mass.

Explanation:

Percentage of element in compound :

$=\frac{\text{number of atoms}\times text{Atomic mass}}{\text{molar mas of compound}}\times 100$

(a) Urea, $(NH_2)_2CO$

Molar mass of urea = 60 g/mol

Atomic mass of nitrogen = 14 g/mol

Number of nitrogen atoms = 2

$N\%=\frac{2\times 14 g/mol}{60 g/mol}\times 100=46.67\%$

(b) Ammonium nitrate, $NH_4NO_3$

Molar mass of ammonium nitrate = 80 g/mol

Atomic mass of nitrogen = 14 g/mol

Number of nitrogen atoms = 2

$N\%=\frac{2\times 14 g/mol}{80 g/mol}\times 100=35.00\%$

(c) Nitric oxide, NO

Molar mass of nitric oxide = 30 g/mol

Atomic mass of nitrogen = 14 g/mol

Number of nitrogen atoms = 1

$N\%=\frac{1\times 14 g/mol}{30 g/mol}\times 100=46.67\%$

(d) Ammonia, $NH_3$

Molar mass of ammona = 17 g/mol

Atomic mass of nitrogen = 14 g/mol

Number of nitrogen atoms = 1

$N\%=\frac{1\times 14 g/mol}{17 g/mol}\times 100=82.35\%$

Ammonia is the richest source of nitrogen on a mass percentage basis because it has 82.35% of nitrogen by mass.

4 0

3 years ago

What ions represent an acid? What ions represent a base?

ira [324]

Answer:

Acid: H^+ Base: OH^- Have a great day.....

Explanation:

3 0

3 years ago

2. Define and describe a mixture using examples.

netineya [11]

A mixture is a substance made by combining two or more different materials in such a way that no chemical reaction occurs.

A mixture can usually be separated back into its original components. Some examples of mixtures are a tossed salad, salt water and a mixed bag of M&M's candy.

5 0

3 years ago