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3 years ago

How many neutrons does X have if it’s atomic number is 28 and it’s mass number is 71

1 answer:

8 0

We know that the mass number is equal to the number of protons plus the number of neutrons. We also know that the atomic number is the same number as the number of protons. Therefore, we can solve for the number of neutrons with what we were given:

x + 28 = 71
x=43

There are 43 neutrons

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Given the following reaction:

fredd [130]

Answer:D. In order to restore equilibrium, the reaction shifts right, towards products

Explanation:

7 0

2 years ago

½H2(g) + ½I2(g) → HI(g), ΔH = +6.2 kcal/mole 21.0 kcal/mole + C(s) + 2S(s) → CS2(l) What type of reaction is represented by the

wlad13 [49]

Answer:

Exothermic Reaction are those reaction, in which energy is released while in endothermic reaction are those, in which energy is absorbed.

Explanation:

First Reaction:

As in this reaction, energy is released

½H2(g) + ½I2(g) → HI(g), ΔH = +6.2 kcal/mole

so it is exothermic reaction

Second reaction:

As in this reaction, energy is absorbed

21.0 kcal/mole + C(s) + 2S(s) → CS2(l)

so it is endothermic reactions.

7 0

3 years ago

Read 2 more answers

What concentrations of acetic acid (pKa = 4.76) and acetate would be required to prepare a 0.15 M buffer solution at pH 5.0? Not

Leni [432]

Answer:

Acetic acid 0,055M and acetate 0,095M.

Explanation:

It is possible to prepare a 0,15M buffer of acetic acid/acetate at pH 5,0 using Henderson-Hasselblach formula, thus:

pH = pka + log₁₀ [A⁻]/[HA] -Where A⁻ is acetate ion and HA is acetic acid-

Replacing:

5,0 = 4,76 + log₁₀ [A⁻]/[HA]

1,7378 = [A⁻]/[HA] (1)

As concentration of buffer is 0,15M, it is possible to write:

[A⁻] + [HA] = 0,15M (2)

Replacing (1) in (2):

1,7378[HA] + [HA] = 0,15M

2,7378[HA] = 0,15M

[HA] = 0,055M

Thus, [A⁻] = 0,095M

That means you need acetic acid 0,055M and acetate 0,095M to obtain the buffer you need.

i hope it helps!

7 0

3 years ago

Indicate which reaction will occur faster. explain your reasoning. select the single best answer. solvolysis of 1−chloro−2,2−dim

Radda [10]

The tert-butyl chloride in ethanol would surely react faster than the solvolysis of 1-chloro-2,2-dimethyl propane. It is known that both reactions are under the SN2 category so it would be hard for these reactions to occur. However, SN1 reactions are possible because of the ethanol which is a polar solvent. Both would form carbocations but tert-butyl chloride forms a more stable carbocation while the 1-chloro-2,2-dimethyl propane forms a primary carbocation only.

6 0

3 years ago

Put the following metric units in order from largest to smallest pL, mL, dL, kL

earnstyle [38]

Answer:

kL, dL, mL, pL

Explanation:

pL stands for picoliters. This is equal to 1 × 10⁻¹² (0.000000000001) liters.

mL stands for milliliters. This is equal to 1 × 10⁻³ (0.001) liters.

dL stands for deciliters. This is equal to 1 × 10⁻¹ (0.1) liters.

kL stands for kiloliters. This is equal to 1 × 10³ (1000) liters.

8 0

3 years ago