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3 years ago

Which of the following best describes alternating current? ________

Chemistry

2 answers:

Alenkasestr [34]3 years ago

7 0

B. Current in which charges change direction

Natali [406]3 years ago

3 0

B. A current in charges change direction

Explanation: an electric current that reverses its direction many times a second at regular intervals, typically used in power supplies.

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Which of the following are isotopes, choose all that apply.

Juliette [100K]

Answer:

Element X with atomic number 10 and atomic mass 21

Element Z with atomic number 10 and atomic mass 22

Explanation:

Isotopy is the existence of two or more atoms of the same element having the same atomic number but different mass numbers due to the differences in the number of neutrons in their various nuclei.

Isotopes of an element have the same electronic configuration.
They share the same chemical properties
They only differ in their masses.

So, Element X and Z with atomic number 10 which is their number of electrons are isotopes. Their mass number, 21 and 22 differs.

4 0

3 years ago

What is the volume of ammonia produced at 243 K at a pressure of 1.38 atm by the unbalanced reaction on the left if 5740 moles o

Neporo4naja [7]

Answer:

49671 L is the produced volume of ammonia

Explanation:

We think the reaction of ammonia 's production:

N₂(g) + 3H₂(g) → 2NH₃ (g)

We have the moles of each reactant so let's determine the limiting reactant:

Ratio is 1:3. 1 mol of nitrogen reacts with 3 moles of H₂

Then, 1720 moles of N₂ will react with (1720 .3) /1 = 5160 moles of H₂

We have 5740 moles of hydrogen, so we have enough hydrogen. This is the excess reagent, so the limiting is the N₂

1 mol of N₂ can produce 2 moles of ammonia

Therefore 1720 moles of N₂ will produce (1720 . 2) /1 = 3440 moles of NH₃

We apply now, the Ideal Gases Law → P . V = n . R .T

V = (n . R . T) /P → V = (3440 mol . 0.082 L.atm/mol.K . 243K) / 1.38 atm

V = 49671 L

We confirm that the nitrogen was the limiting reactant

3 moles of H₂ need 1 mol of nitrogen to react

Therefore, 5740 moles of H₂ will react with (5740 . 1) /3 = 1913 moles of N₂

It was ok to say, that N₂ was the limiting reactant because we need 1913 moles in the reaction, and we only have 1720 moles

6 0

3 years ago

How many moles are there in 13g of KMnO4?

Hoochie [10]

Answer:

0.08 moles

Explanation:

Relative atomic mass of KMnO4 = K + Mn + O4 = 39 + 55 + 16 x 4 = 158

=> Moles in 13g of KMnO4 = $\frac{Mass}{Relative-atomic-mass}$ = $\frac{13}{158}$ = 0.082278.. = 0.08 moles

3 0

3 years ago

Read 2 more answers

What does AS> O mean?

Vlad1618 [11]

Answer:

ΔS> 0 means Letter A

Explanation:

Processes that involve an increase in entropy of the system (ΔS > 0) are very often spontaneous; however, examples to the contrary are plentiful. By expanding consideration of entropy changes to include the surroundings, we may reach a significant conclusion regarding the relation between this property and spontaneity. In thermodynamic models, the system and surroundings comprise everything, that is, the universe, and so the following is true:

\displaystyle \Delta {S}_{\text{univ}}=\Delta {S}_{\text{sys}}+\Delta {S}_{\text{surr}}

5 0

3 years ago

What compound is formed when methyloxirane (1,2-epoxypropane) is reacted with ethylmagnesium bromide followed by treatment with

Pavlova-9 [17]

Answer:

Pentan-2-ol

Explanation:

On this reaction, we have a Grignard reagent (ethylmagnesium bromide), therefore we will have the production of a carbanion (step 1). Then this carbanion can attack the least substituted carbon in the epoxide in this case carbon 1 (step 2). In this step, the epoxide is open and a negative charge is generated in the oxygen. The next step, is the treatment with aqueous acid, when we add acid the hydronium ion ( $H^+$ ) would be produced, so in the reaction mechanism, we can put the hydronium ion. This ion would be attacked by the negative charge produced in the second step to produce the final molecule: "Pentan-2-ol".

See figure 1

I hope it helps!

5 0

3 years ago