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3 years ago

You combine 13 g of magnesium with 5 g of nitrogen to form a compound.

Chemistry

1 answer:

guapka [62]3 years ago

7 0

Answer:

$\large \boxed{28 \, \% }$

Explanation:

magnesium + nitrogen ⟶ Product

13 g 5 g

Mass of product = 13 g + 5 g = 18 g

The product contains 5 g of nitrogen .

$\text{Percent N} = \dfrac{\text{5 g}}{\text{18 g}} \times \, 100\% = \mathbf{28 \, \%}\\\text{The percent by mass of nitrogen is $\large \boxed{\mathbf{28 \, \% }}$}$

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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!

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3 years ago

What is the most appropriate unit of astronomical distance to represent the distance between an earth an orbiting space station

Reil [10]

Astronauts use "Astronomical Unit" to measure the distance between planets in our solar system "only". To measure long distances like between 2 galaxies, they use "light years". One Astronomical Unit = Average distance between sun and earth which is equal to 149.6 million kilometers. Ping me if you have any doubt.

4 0

3 years ago

Calculate the molecular weight of a substance. In which the solution of this substance in the water has a concentration of 7 per

Eduardwww [97]

Answer : The molecular weight of a substance is 157.3 g/mol

Explanation :

As we are given that 7 % by weight that means 7 grams of solute present in 100 grams of solution.

Mass of solute = 7 g

Mass of solution = 100 g

Mass of solvent = 100 - 7 = 93 g

Formula used :

$\Delta T_f=i\times K_f\times m\\\\T_f^o-T_f=k_f\times\frac{\text{Mass of substance(solute)}\times 1000}{\text{Molar mass of substance(solute)}\times \text{Mass of water(solvent)}}$

where,

$\Delta T_f$ = change in freezing point

$T_f^o$ = temperature of pure water = $0^oC$

$T_f$ = temperature of solution = $-0.89^oC$

$K_f$ = freezing point constant of water = $1.86^oC/m$

m = molality

Now put all the given values in this formula, we get

$(0-(-0.89))^oC=1.86^oC/m\times \frac{7g\times 1000}{\text{Molar mass of substance(solute)}\times 93g}$

$\text{Molar mass of substance(solute)}=157.3g/mol$

Therefore, the molecular weight of a substance is 157.3 g/mol

7 0

3 years ago

The half-life for the radioactive decay of ce−141 is 32.5 days. if a sample has an activity of 3.8 μci after 162.5 d have elapse

Umnica [9.8K]

Answer : 121.5 μCi

Explanation : We have Ce-141 half life given as 32.5 days so if the activity is 3.8 μci after 162.5 days of time elapsed we have to find the initial activity.

We can use this formula;

 $\frac{N}{ N_{0} } = e^{-( \frac{0.693 X T_{2} }{T_{1}})$

3.8 / $N_{0}$ = $e^$ ((0.693 X 162.5 ) / 32.5) = 121.5

On solving we get, The initial activity as 121.5 μci

5 0

3 years ago

Read 2 more answers

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:

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