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3 years ago

Given the problem below, what would the first step be in solving it?

Chemistry

1 answer:

Hoochie [10]3 years ago

4 0

Answer:

First step would be convert to moles

Final Answer: 37.8 g of NaCl

Explanation:

The reaction is:

2Na + Cl₂ → 2NaCI

We convert the mass of each reactant to moles:

18 g . 1mol /23g = 0.783 moles of Na

23g . 1mol / 70.9g = 0.324 moles of chlorine

We use the mole ratio to determine the limiting reactant:

Ratio is 2:1. 2 moles of Na react to 1 mol of chlorine

Then, 0.783 moles of Na, may react to (0.783 . 1)/2 = 0.391 moles.

Excellent!. We need 0.391 moles of Cl₂ and we only have 0.324 moles available. That's why the Cl₂ is our limiting reactant.

We use the mole ratio again, with the product side. (1:2)

1 mol of Cl₂ can produce 2 moles of NaCl

Then, our 0.324 moles of gas, may produce (0.324 . 2)/1 = 0.648 moles

Finally, we convert the moles to grams:

0.648 mol . 58.45g/mol =

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Lithium reacts with bromine (Br2) in a synthesis reaction to produce lithium bromide. Determine the limiting reactant if 25.0 gr

Lunna [17]

Answer: Bromine is the limiting reactant

Explanation:

First of all let's generate a balanced equation for the reaction

2Li + Br2 —> 2LiBr

Molar Mass of Li = 7g/mol

Molar Mass of Br2 = 2x80 = 160g/mol

From the question given, were told that 25g of Li and 25g Br2 were present at the take-off of the reaction. Converting these Masses to mole, we have:

Number of mole of Li = 25/7 = 3.6moles

Number of mole of Br2 = 25/160 = 0.156mol.

To know which is the limiting reactant, we have to compare the ratio of the number of mole of experimental Li and Br2 to that of theoretical Li and Br2

For the experimental yield:

Li : Br2 = 3.6/ 0.156 = 23 : 1

For the theoretical yield:

Li : Br = 2 : 1

From the above, we see clear that Br2 is the limiting reactant because according to the equation( which gives the theoretical yield), for every 2moles of Li, 1mole of Br2 is used up. But this is not so from the experiment conducted as 23moles required 1mole of Br2.

4 0

3 years ago

Calculate the mass in grams of 7.88 mol of RbMnO4

vitfil [10]

Molar mass RbMnO₄ = 204.40 g/mol

1 mole ---------- 204.40 g
7.88 mole ------ ?

mass = 7.88 * 204.40 / 1

mass = 1610.672 g

hope this helps!

8 0

3 years ago

At 63.5 C the vapor pressure of H2O is 175 torr and that of ethanol is 400 torr. A solution is made by adding equal masses of H2

xxTIMURxx [149]

Answer:

Moel fraction of ethanol in the solution = 0.28

Vapor pressure of the solution = 238 torr

Mole fraction of ethanol in the vapor = 0.47

Explanation:

Let's use 100 g of each substance as a calculus basis. Knowing that the molar mass of water is 18 g/mol and the molar mass of ethanol is 46 g/mol, the number of moles (n = mass/molar mass) of each one is:

nw = 100/18 = 5.56 mol

ne= 100/46 = 2.17 mol

The total number of moles is 7.73 mol, so the mole fraction of ethanol is

2.17/7.73 = 0.28

The mole fraction of water must be 0.72, so if we assume that the solution is ideal, by the Raoult's law, the solution vapor pressure is the sum of the multiplication of the mole fraction by the vapor pressure of each substance, thus:

P = 0.28*400 + 0.72*175

P = 238 torr

The partial pressure of each substance can be found by the multiplication of the molar fraction by the vapor pressure, thus:

Pw = 0.72*175 = 126 torr

Pe = 0.28*400 = 112 torr

To know the number of moles that is vaporized above the solution, we may use the ideal gas law:

PV = nRT

P/n = RT/V

R is the gas constant, T is the temperature and V is the volume, so they are the same for both water and ethanol, thus

Pw/nw = Pe/ne

126/nw = 112/ne

ne = (112/126)*nw

ne = 0.89nw

So, the mole fraction of ethanol is:

ne/(ne + nw) = 0.89nw/(0.89nw + nw) = 0.89/1.89 = 0.47

4 0

3 years ago

Could the structures below undergo a Fischer esterification reaction? Reaction scheme of benzoic acid and thionyl chloride to fo

Romashka-Z-Leto [24]

Answer:

The correct answer is the first option. No, the structures above cannot undergo a Fischer esterification reaction to form an ester.

Explanation:

The reaction that will take place can be found in the attached file. The reaction does not require any catalyst and it cannot undergo a Fischer esterification reaction to form an ester.

4 0

3 years ago

WORTH 80 POINTS PLEASE HELP

Verdich [7]

The two bulges are called tidal bulges. There are two tidal bulges on opposite sides of Earth. One is beneath the moon and the other is opposite to that. The one below the moon is thought of as gravitational. It is produced by gravitational attraction between water molecules in the ocean and the moon.

<span>Now, about the other bulge. Think about inertia and what happens when masses rotate around a single point. Imagine yourself swinging a bucket of any liquid with your arm in a circular gesture. Even as the bucket goes over your head, the water is still held in the bucket and doesn't splash all over you. This rotation creates a centrifugal force. A similar event occurs during the lunar month as the earth/moon system rotates. The moon orbits the earth, but the rotation axis for this orbit isn't earth's center. Both the moon and Earth move during the roughly 28-day period it takes for the orbit, and because of this, water in the ocean is thrown to the outside, the same as the water in your bucket. The tidal bulge on the opposite side of Earth from the moon is produced by this inertial effect, referred to as centrifugal force.</span>

5 0

3 years ago

Read 2 more answers