Balance in basic solution: O2(g) + Cr³+ (aq) → H₂O2 (1) + Cr₂O7²- (aq)

Calculate the concentration imports per million ppm of DDT if a sample size of 5000 g contained 0.10 g DDT

nevsk [136]

Answer:

20ppm

Explanation:

parts per million are defined as the mass of solute in mg (In this case, mass of DDT) per kg of sample.

To solve this question we must find the mass of DDT in mg and the mass of sample in kg:

Mass DDT:

0.10g * (1000mg / 1g) = 100mg

Mass sample:

5000g * (1kg / 1000g) = 5kg

Parts per Million:

100mg / 5kg =

3 0

3 years ago

If a sample contains 70.0 % of the R enantiomer and 30.0 % of the S enantiomer, what is the enantiomeric excess of the mixture?

NeTakaya

Answer:

the enantiomeric excess of the mixture is 40%

Explanation:

The computation of the enantiomeric excess of the mixture is shown below:

As we know that

$= |\frac{R - S}{R + S} |\times 100\\\\= |\frac{70 - 30}{70 + 30}| \times 100\\\\= 40\%$

Hence, the enantiomeric excess of the mixture is 40%

3 0

3 years ago

In Haber’s process, 30 moles of hydrogen and 30 moles of nitrogen react to make ammonia. If the yield of the product is 50%, wha

devlian [24]

Answer:

Therewill be produced 170.6 grams NH3, there will remain 25 moles of N2, this is 700 grams

Explanation:

Step 1: Data given

Number of moles hydrogen = 30 moles

Number of moles nitrogen = 30 moles

Yield = 50 %

Molar mass of N2 = 28 g/mol

Molar mass of H2 = 2.02 g/mol

Molar mass of NH3 = 17.03 g/mol

Step 2: The balanced equation

N2 + 3H2 → 2NH3

Step 3: Calculate limiting reactant

For 1 mol of N2, we need 3 moles of H2 to produce 2 moles of NH3

Hydrogen is the limiting reactant.

The 30 moles will be completely be consumed.

N2 is in excess. There will react 30/3 =10 moles

There will remain 30 -10 = 20 moles (this in the case of a 100% yield)

In a 50 % yield, there will remain 20 + 0,5*10 = 25 moles. there will react 5 moles.

Step 4: Calculate moles of NH3

There will be produced, 30/ (3/2) = 20 moles of NH3 (In case of 100% yield)

For a 50% yield there will be produced, 10 moles of NH3

Step 5: Calculate the mass of NH3

Mass of NH3 = mol NH3 * Molar mass NH3

Mass of NH3 = 20 moles * 17.03

Mass of NH3 = 340.6 grams = theoretical yield ( 100% yield)

Step 6: Calculate actual mass

50% yield = actual mass / theoretical mass

actual mass = 0.5 * 340.6

actual mass = 170.3 grams

Step 7: The mass of nitrogen remaining

There remain 20 moles of nitrogen + 50% of 10 moles = 25 moles remain

Mass of nitrogen = 25 moles * 28 g/mol

Mass of nitrogen = 700 grams

6 0

4 years ago

Read 2 more answers

A 1.268 g sample of a metal carbonate, MCO₃, was treated 100.00 mL of 0.1083 M H₂SO₄, yielding CO₂ gas and an aqueous solution o

attashe74 [19]

Answer:

MCO3 is BaCO3

The mass of CO2 produced is 0.28g of CO2

Explanation:

The first step in solving the question is to put down the balanced reaction equations as shown in the image attached. Secondly, we obtain the relative number of moles acid and base as mentioned in the question. The balanced neutralization reaction equation is used to obtain the number of moles of excess acid involved in the neutralization reaction.

This is then subtracted from the total number of moles acid to give the number of moles of acid that reacted with MCO3. From here, the molar mass of MCO3 and identity of M can be found. Hence the mass of CO2 produced is calculated as shown.

6 0

3 years ago

10) Explain what arsenic had to do with preserving bodies in the past and how that related to Sylvester’s body. Tell me how the

Salsk061 [2.6K]

10) Arsenic is a chemical agent which was used in preserving dead bodies in the past. It is mainly a formaldehyde mixture with coloring agents to give a dead body the look of life. Sylvester was a third mummy that was embalmed with arsenic in the late 1800s and is now on exhibit at Ye Olde Curiosity Shop in Seattle, Washington. His mummified body showed an extremely unusual since the remains weighed approximately 80 lbs when a body is composed of 70-80% water, after dehydration, the weight should be about 20-30% the premortem weight. The solution was also used during Civil War to preserve dead bodies as the dead were being shipped home from the battlefield.

9) Research can yield dates when certain plants/animals became domesticated and entered the standard diets of people, meaning you would not see masses eating beef before the cow became domesticated. To further this you can look at when a specific food was introduced into the diets of people in the geographic area of the person you are studying.

5 0

4 years ago