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3 years ago

How many neutrons do (k) potassium-39 and potassium-40 have, respectively?

1 answer:

7 0

Potassium’s atomic number in periodic table is 19, Potassium can only have a mass numbers of 41, 40 and 39. Potassium 39, 40, and 41 are all different isotopes of the element potassium. Each of the isotopes has 19 electrons and 19 protons but the number of neutrons vary. So, in your question Potassium-39 has twenty (20) neutrons, and potassium-40 has 21 neutrons.

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How do lawmakers make good environmental decisions??

Sliva [168]

<h2>Answer : By weighing the costs and benefits of an environmental issue </h2><h3> Explanation :</h3>

The law makers usually conduct many studies before a law is imposed. They try to explore many other options available to the current environmental issue and then come to a conclusion to make a law.

They also weigh the cost aspect along with the benefit of the ongoing environmental issue. They try to come up with something which appears to be cost effective and result bearing.

4 0

2 years ago

What is the mass of 2.5 mol of ca, which has a molar mass of g/mol

swat32

Atomic mass Ca = 40 a.m.u

1 mole Ca ----------- 40 g
2.5 mols Ca -------- ( mass Ca )

Mass Ca = 2.5 x 40 / 1

Mass Ca = 100 / 1

= 100 g of Ca

hope this helps!

3 0

3 years ago

Construct a three-step synthesis of trans-2-pentene from acetylene by dragging the appropriate formulas into the bins. Note that

adelina 88 [10]

Answer:

The three-step synthesis of trans-2-pentene from acetylene is as follows.

<u>Step -1:</u> Formation of higher order terminal alkyne on reaction with sodium acetylides with haloalkanes.

<u>Step -2:</u> Formation terminal alkyne to nonterminal alkynes.

<u>Step -3:</u> Formation of trans-pent - 2-pent-ene by reduction.

Explanation:

Synthesis of trans-pent-2-yne from ethyne takes place is mainly a three step synthesis which involves formation of higher order terminal alkyne on reaction with sodium acetylides with haloalkane. Second step involves the further alkylation of terminal alkynes to higher order nonterminal alkynes and the third step involves the formation of trans-2-ene by dissolving reduction method.

The chemical reaction of each step of chemical reactions is as follows.

8 0

3 years ago

For the reaction PC15 (8) PC13 (g) + Cl2 (g) K = 0.0454 at 261 °C. If a vessel is filled with these gases such that the initial

Fiesta28 [93]

Answer:

The correct answer is B.

The $K_{eq}$ is samller than $Q$ of the reaction . So,the reaction will shift towards the left i.e. towards the reactant side.

Explanation:

Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as $K_{eq}$

K is the constant of a certain reaction when it is in equilibrium, while Q is the quotient of activities of products and reactants at any stage other than equilibrium of a reaction.

For the given chemical reaction:

$PCl_5(g)\rightleftharpoons PCl_3(g)+Cl_2(g)$

The expression for $Q$ is written as:

$Q=\frac{[PCl_3][Cl_2]}{[[PCl_5]^1}$

$Q=\frac{0.20 M\times 2.5 M}{0.20 M}$

$Q=2.5$

Given : $K_{eq}$ = 0.0454

Thus as $K_{eq}$ , the reaction will shift towards the left i.e. towards the reactant side.

4 0

3 years ago

Read 2 more answers

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2mg(s) + o2(g) → 2mgo(s) how many moles of o2 are

Naddik [55]

Answer is: 0,275 moles of oxygen are consumed.
Chemical reaction: 2Mg + O₂ → 2MgO.
n(Mg) = 0,550 mol.
n(O₂) = ?
from chemical reaction: n(Mg) : n(O₂) = 2 : 1.
0,550 mol : n(O₂) = 2 : 1.
2n(O₂) = 0,550 mol.
n(O₂) = 0,275 mol.
n - amount of substance.

4 0

2 years ago

Read 2 more answers