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4 years ago

Someone plz hello me ASAP it would be appreciated on question 9 btw

Chemistry

1 answer:

Otrada [13]4 years ago

7 0

Answer:

Explanation:

The water is being stored for the time being, and potential energy is, essentially, defined like that. Once the energy is utilized, it will turn into kinetic energy.

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The reaction between ethyne (acetylene, C 2 H 2 ) and hydrogen. The product is ethane (C 2 H 6 ). Which is the limiting reactant

serious [3.7K]

Answer:

Three possible cases:

- If amount are equal for each reactant (for example 1 mol each), the limiting is the hydrogen and the excess reagent is the acetylene.

- When moles of H₂ are greater than C₂H₂

The acetylene is the limiting reagent so the H₂ is the excess

- When moles of C₂H₂ are greater than H₂

For this case, H₂ is the limiting reactant and the excess is the C₂H₂

Explanation:

First of all we determine the reaction:

Reactants, acetylene and hydrogen

Products are ethane

Then, the balanced reaction is: C₂H₂ + 2H₂ → C₂H₆

1 mol of acetylene reacts with 2 moles of hydrogen ir order to produce 1 mol of ethane.

If amount are equal for each reactant, the limiting is the hydrogen,

For example, 1 mol each

For 1 mol of acetylene I need 2 moles of H₂. I've only got 1 mol, so I do not have enough H₂. The excess reagent is the acetylene.

- When moles of H₂ are greater than C₂H₂

For example, 3 moles of H₂ and 0.5 mol of C₂H₂

2moles of H₂ need 1 mol of C₂H₂ for the reaction

Then 3 moles of H₂ will need (3 . 1) / 2 = 1.5 moles

We have 0.5 moles, so the acetylene is the limiting reagent, again.

- When moles of C₂H₂ are greater than H₂

For example 1 mol of C₂H₂ and 0.001 moles of H₂

If I have 1 mol of C₂H₂, I definetly need the double of moles of hydrogen, so in this case, H₂ is the limiting reactant and the excess is the C₂H₂

If we have 1 mol of H₂ and 0.5 mol of C₂H₂, notice that moles of acetylene are lower than hydrogen

1 mol of C₂H₂ needs 2 moles of H₂

So 0.5 moles of C₂H₂ will need 1 mol of H₂ (it's ok because we have 1 mol)

2 moles of H₂ need 1 mol of C₂H₂ for reaction

Then, 1 mol of H₂ will need 0.5 moles of C₂H₂ (it's ok because we have that amount)

In this case, there is no excess neither limiting. That's why we can choose any of them to determine the moles (or mass) for the product

7 0

3 years ago

Having done the experiment, explain briefly how the mass of zinc not equal the mass of lead gained (hint: the periodic table)

masya89 [10]

Answer:

Due to the difference in the relative atomic masses and therefore, the molecular masses of Zn and Pb, one mole of Zn is about 3.2 times lighter than one mole of Pb

Explanation:

From the periodic table, we have;

The atomic number of zinc, Zn = 30

The atomic mass of zinc, Zn = 65.38 amu

The molar mass of zinc, Zn = 65.38 g/mol

The atomic number of lead, Pb = 82

The atomic mass of lead, Pb = 207.2 amu

The molar mass of lead, Pb = 207.2 g/mol

Therefore, whereby equal number of moles of Zn is lost and Pb is gained, we have;

Mass of 1 mole of Zn = 65.38 grams

Therefore, 1 gram of Zn = 1/65.38 moles = 0.0153 moles

0.12 grams of Zn = 0.12×0.0153 = 0.00184 moles of Zn

Given that equal number of moles of Zn and Pb are involved in the reaction, the number of moles of Pb gained = 0.00184 moles

The mass of Pb gained = Number of moles of Pb gained × Molar mass of Pb

The mass of Pb gained = 0.00184 × 207.2 = 0.38 g ≈ 0.4 g.

Amount of Pb gained = 0.43 g ≈ 0.4 g

4 0

3 years ago

261 nm to millimeters

Komok [63]

The answer is <span>0.000261 millimeters</span>

5 0

3 years ago

How much heat is absorbed by a 112.5 g sample of water when it is heated from 12.5 °C to 92.1 °C? (Specific heat capacity of wat

Alborosie

Answer:

$\boxed {\boxed {\sf37,467.72 \ Joules }}$

Explanation:

We are asked to find how much heat a sample of water absorbed. Since we are given the mass, temperature, and specific heat, we will use the following formula.

$q=mc \Delta T$

The mass (m) of the sample is 112.5 grams. The specific heat capacity of water (c) is 4.184 Joules per gram degree Celsius. The difference in temperature (ΔT) is found by subtracting the initial temperature from the final temperature.