I need help with this question please!!

How many liters of oxygen gas (O2) are needed to produce 100 kJ of energy at STP? 2C6H6(I) + 1502(g) —> 12CO2(g)+6H2O(g)+3909

makkiz [27]

Answer: 8.59 L of oxygen gas are needed to produce 100 kJ of energy at STP

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number $6.023\times 10^{23}$ of particles.

Standard condition of temperature (STP) is 273 K and atmospheric pressure is 1 atmosphere respectively.

1 mole of every gas occupy volume at STP = 22.4 L

The balanced chemical reaction is:

$2C_6H_6(I)+15O_2(g)\rightarrow 12CO_2(g)+6H_2O(g)$

3909.9 kJ of of energy is produced by = $15\times 22.4=336L$

100 kJ of oxygen gas are needed to produce = $\frac{336}{3909.9}\times 100=8.59L$

7 0

2 years ago

Calculate the freezing point (in degrees C) of a solution made by dissolving 7.99 g of anthracene{C14H10} in 79 g of benzene. Th

mario62 [17]

<u>Answer:</u> The freezing point of solution is 2.6°C

<u>Explanation:</u>

To calculate the depression in freezing point, we use the equation:

$\Delta T_f=iK_fm$

Or,

$\Delta T_f=i\times K_f\times \frac{m_{solute}\times 1000}{M_{solute}\times W_{solvent}\text{ in grams}}$

where,

$\Delta T_f$ = $\text{Freezing point of pure solution}-\text{Freezing point of solution}$

Freezing point of pure solution = 5.5°C

i = Vant hoff factor = 1 (For non-electrolytes)

$K_f$ = molal freezing point depression constant = 5.12 K/m = 5.12 °C/m

$m_{solute}$ = Given mass of solute (anthracene) = 7.99 g

$M_{solute}$ = Molar mass of solute (anthracene) = 178.23 g/mol

$W_{solvent}$ = Mass of solvent (benzene) = 79 g

Putting values in above equation, we get:

$5.5-\text{Freezing point of solution}=1\times 5.12^oC/m\times \frac{7.99\times 1000}{178.23g/mol\times 79}\\\\\text{Freezing point of solution}=2.6^oC$

Hence, the freezing point of solution is 2.6°C

8 0

2 years ago

A box of jello has a mass of 250 g. How many boxes must be bought to have 1 Kg of jello? *

zhuklara [117]

Answer:

Number of boxes = 4

Explanation:

Given:

Mass of one box of jello = 250 grams

Total quantity want to purchase = 1 kg = 1 × 1,000 gram = 1,000 grams

Find:

Number of boxes in 1,000 grams = ?

Computation:

Number of boxes = Total quantity want to purchase / Mass of one box of jello

Number of boxes = 1,000 / 250

Number of boxes = 4

Therefore, 4 boxes of jello must be purchase to get 1 kg of Jello.

8 0

2 years ago

Assume that a point mutation changes the codon AUU to AUC. Why is this a neutral mutation

lukranit [14]

I used the genetic code table. mRNA codon ===> amino acid

1st base 2nd base 3rd base
A U U ===> Isoleucine
A U C ===> Isoleucine

The point mutation of codon AUU to AUC is a neutral mutation because it neither benefits nor deter the ability of the organism to survive and reproduce.

As you can see, Both codons result to the Isoleucine amino acid.

Another codon that will still result to the Isoleucin amino acid is AUA.

3 0

2 years ago

A 0.1326 g sample of magnesium was burned in an oxygen bomb calorimeter. the total heat capacity of the calorimeter plus water w

Sladkaya [172]

Answer: Th enthalpy of combustion for the given reaction is 594.244 kJ/mol

Explanation: Enthalpy of combustion is defined as the decomposition of a substance in the presence of oxygen gas.

W are given a chemical reaction:

$Mg(s)+\frac{1}{2}O_2(g)\rightarrow MgO(s)$

$c=5760J/^oC$

$\Delta T=0.570^oC$

To calculate the enthalpy change, we use the formula:

$\Delta H=c\Delta T\\\\\Delta H=5760J/^oC\times 0.570^oC=3283.2J$

This is the amount of energy released when 0.1326 grams of sample was burned.

So, energy released when 1 gram of sample was burned is = $\frac{3283.2J}{0.1326g}=24760.181J/g$

Energy 1 mole of magnesium is being combusted, so to calculate the energy released when 1 mole of magnesium ( that is 24 g/mol of magnesium) is being combusted will be:

$\Delta H=24760.181J/g\times 24g/mol\\\\\Delta H=594244.3J/mol\\\\\Delta H=594.244kJ/mol$

4 0

2 years ago