Ask question

Ask question

All categories

3 years ago

11

1. What is the theoretical  yield of C6H5Br in this reaction when 30.0 g of C6H6 reacts with excess Br2? If the  actual yield of

C6H5Br was 56.7  g,  what  is  the  percent  yield?

1 answer:

Rudiy273 years ago

5 0

Answer:

The theoretical yield in grams is 60.292 grams, and in moles the theoretical yield is 0.384. The percent yield is 94%.

Explanation:

You might be interested in

Please help last assignment of the day

Andrej [43]

In this qn, you use the mole formula,

amount (mol) = mass (g) ÷ molar mass

(molar mass is the mass number of an element, which u can find by referring to the periodic table)

so by subbing in the values given to you, you can find the answer

5. amount of Cu = 55.9 ÷ 63.5 = 0.880mol (3sf)

6. amount of N2 = 340 ÷ 2(14.0) = 12.1mol (3sf)

(note: you multiply the molar mass of N by 2 as there are 2 N atoms)

for qn 7 and 8, youre finding the mass and not the amount. By bringing the molar mass over to the other side of the formula, you get

mass = amount (mol) × molar mass

thus,

7. mass of Fe = 0.063 × 55.8 = 3.52g (3sf)

8. mass of H2 = 94.7 × 2(1.0) = 47.4g (3sf)

extra things to take note of:

- likewise, you can also find the molar mass of an element by using

molar mass = mass(g) ÷ amount(mol)

^^ this is commonly only needed when you need to find the molar mass of an isotope. the question will give you the amount and mass of the element, and you just need to factor them in to find your answer.

- typically, you use 3 sf in your final answer and 5sf in your working. remember to write (3sf) at the end of your number statement when necessary.

- when you get an answer of (eg.) 0.6mol, you still need to write it in 3sf, so your answer would be 0.600mol

3 0

3 years ago

hich statement is true? A. An acid with a large pKa will be a better conductor of electricity than one with a smaller pKa. B. An

xz_007 [3.2K]

Answer:

$\boxed{\text{B is correct}}$

Explanation:

Kₐ and pKₐ are measures of the strength of an acid. For example,

HX + H₂O ⇌ H₃O⁺ + X⁻; Kₐ = 10¹⁰, pKₐ = -10

HA + H₂O ⇌ H₃O⁺ + A⁻; Kₐ = 10⁻¹⁰, pKₐ = 10

HX is a strong acid, because it has a larger Kₐ, that is, the position of equilibrium lies far to the right.

However, pKₐ is the negative logarithm of Kₐ, so HX has the smaller pKₐ.

Similarly, Ha is a weak acid, but it has the larger pKₐ.

Strong acid: Large Kₐ ⇔ Low pKₐ

Weak acid: Small Kₐ ⇔ High pKₐ

A is wrong. HA is a weak acid, so it produces only a few hydronium ions.

B is correct. The rate of corrosion depends on the concentration of hydronium ions. HA is a weak acid, so it is less corrosive than an acid with a small pKₐ.

C is wrong. HX is a strong acid, so there are more ions to carry the current. HX will be a good conductor of electricity.

D is wrong. HX is a strong acid, so it provides more hydronium ions and is more corrosive.

E is wrong. HX is a strong acid, so it provides more hydronium ions to stimulate the taste buds.

$\boxed{\textbf{B is correct}}$

7 0

3 years ago

Which is not a form of potential energy?<br><br> gravitational<br> chemical<br> elastic<br> thermal

Elena L [17]

Answer:Thermal Energy is not a form of potential energy

Explanation:

4 0

3 years ago

Aluminum reacts with chlorine gas to form aluminum chloride via the following reaction: 2Al(s)+3Cl2(g)→2AlCl3(s) What is the max

jolli1 [7]

<u>Answer:</u> The mass of aluminium chloride that can be formed are 46.3 g

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ....(1)

<u>For Aluminium:</u>

Given mass of aluminium = 32 g

Molar mass of aluminium = 26.98 g/mol

Putting values in above equation, we get:

$\text{Moles of aluminium}=\frac{32g}{26.98g/mol}=1.186mol$

<u>For Chlorine:</u>

Given mass of chlorine = 37 g

Molar mass of chlorine = 71 g/mol

Putting values in above equation, we get:

$\text{Moles of chlorine gas}=\frac{37g}{71g/mol}=0.521mol$

For the given chemical equation:

$2Al(s)+3Cl_2(g)\rightarrow 2AlCl_3(s)$

By Stoichiometry of the reaction:

3 moles of chlorine gas is reacting with 2 moles of aluminium.

So, 0.521 moles of chlorine gas will react with = $\frac{2}{3}\times 0.521=0.347moles$ of aluminium.

As, given amount of aluminium is more than the required amount. Thus, it is considered as an excess reagent.

So, chlorine gas is considered as a limiting reagent because it limits the formation of products.

By Stoichiometry of the reaction:

3 moles of chlorine gas is producing 2 moles of aluminium chloride

So, 0.521 moles of chlorine gas will react with = $\frac{2}{3}\times 0.521=0.347moles$ of aluminium chloride.

Now, calculating the mass of aluminium chloride by using equation 1, we get:

Moles of aluminium chloride = 0.347 moles

Molar mass of aluminium chloride = 133.34 g/mol

Putting all the values in equation 1, we get:

$0.347mol=\frac{\text{Mass of aluminium chloride}}{133.34g/mol}\\\\\text{Mass of aluminium chloride}=46.3g$

Hence, the mass of aluminium chloride that can be formed are 46.3 g

7 0

4 years ago

In this lab, you will do experiments to identify types of changes. Using the question format you learned (shown above), write an

Vlad1618 [11]

Answer:

How can you distinguish a physical change from a chemical change?

Explanation:

4 0

3 years ago