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3 years ago

If 1.25 g of water is heated from 20.0 degrees Celsius to 45.0 degrees Celsius and has a specific

Chemistry

1 answer:

umka2103 [35]3 years ago

6 0

Answer: Heat energy contained by water is 130.625 J.

Explanation:

Given: Mass = 1.25 g

Specific heat = $4.18 J/g^{o}C$

Initial temperature = $20.0^{o}C$

Final temperature = $45.0^{o}C$

Formula used to calculate heat energy is as follows.

$q = m \times C \times (T_{2} - T_{1})$

where,

q = heat energy

m = mass of substance

$T_{1}$ = initial temperature

$T_{2}$ = final temperature

Substitute the values into above formula as follows.

$q = m \times C \times (T_{2} - T_{1})\\= 1.25 g \times 4.18 J/g^{o}C \times (45.0 - 20.0)^{o}C\\= 130.625 J$

Thus, we can conclude that heat energy contained by water is 130.625 J.

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A compound with the molecular formula C8H8O produces an IR spectrum with signals at 3063, 1686, and 1646 cm-1. The 1H NMR spectr

pantera1 [17]

Answer:

The data indicates towards a acetophenone molecule (SMILES CC(=O)c1ccccc1). (molecule image is also attached)

Explanation:

Let's first calculate the index of hydrogen deficiency (IHD) of the compound, which helps to determine the degree of unsaturation in a molecule. For hydrocarbons, It can be calculated as

$IHD=\frac{2x+2-y}{2}$

Here, x and y stands for number of carbon and hydrogen atoms respectively.

So,

$IHD=\frac{2\times8+2-8}{2}\\IHD=5$

The IR spectrum shows absorbance at 3063 cm⁻¹, this absorbance is associated with the stretching of C-H bond of the alkane group. Strong absorbance band at 1686 cm⁻¹ indicates the presence of conjugated ketone group. The last absorbance mentioned at 1646 cm⁻¹ is usually associated with the stretching of conjugated C=C bond.

The NMR spectrum shows a singlet at 2.6 ppm with the integration of three H atoms. This peak is attributed to the hydrogen of alpha carbon of carbonyl group. Another peak at 7.5 ppm with integration of 5 hydrogen atoms is a characteristic peak of the hydrogen atoms of the phenyl group.

So, all the data indicates towards a acetophenone molecule (SMILES CC(=O)c1ccccc1). IHD value of 5 satisfies a cyclic ring with three double bonds and a C=O bond. Conjugated ketone (1686 cm⁻¹) group is indicated by the IR spectrum and the phenyl group (7.5 ppm) is indicated by the NMR spectrum. The methyl group next to ketone is predicted by both NMR (2.6 ppm) and FTIR (3063, 1646 cm⁻¹) spectrum

5 0

3 years ago

A mixture of NH3 and N2H4 is placed in a sealed container at 300K. The total pressure is 0.50 atm. The container is heated to 12

kiruha [24]

Answer:

The percent of N2H4 in the original mixture is 25 %

Explanation:

Step 1: Data given

Temperature in the sealed container = 300K

The total pressure = 0.50 atm

The container is heated to 1200K

The total pressure at 1200K = 4.5 atm

Step 2: The balanced equation

2NH3 → N2 + 3H2

N2H4 → N2 + 2H2

Step 3: Calculate the initial moles

p*V = n*R*T

⇒ with p = the total pressure = 0.50 atm

⇒ with V = the volume of the gas

⇒ with n = the total moles of the gasses (n1 + n2)

⇒ with R = the gas constant = 0.08206 L*atm/mol*K

⇒ with T = the temperature in the container = 300

0.50*V= (n1+n2)*R*300

Step 4: after decmposition,

from 2 moles of NH3 we'll get 4 moles (n1 → 2n1)

from 1 moles of N2H4 we'll get 3 moles. (n2 → 3n2)

The total moles for mixture = 2n1 + 3n2

p*V= n*R*T

⇒ with p = the total pressure at 1200 K = 4.5 atm

⇒ V = The volume

⇒ with n = the number of moles

⇒ with R = the gas constant = 0.08206 L* atm/ K*mol

⇒ with T = the temperature = 1200 K

4.5*V = (2n1 + 3n2)*R*1200

0.50*V= (n1+n2)*R*300

Step 5: Calculate the percentage of N2H4

After dividing both equations we get:

n2/(n1+n2) = 1/4

n1 = 3 and n2 = 1

Percentage of N2H4 therfore is => 1*100/4 = 25%

and % of NH3 => 75%

The percent of N2H4 in the original mixture is 25 %

4 0

3 years ago

A solution contains 15 grams of salt per litter of solution. How many grams of salt are in 3.3 litters of solution?

Verizon [17]

49.5g

Explanation:

Mass of salt = 15g

Volume of solution = 1L

Volume of given solution = 3.3L

Unknown:

Mass of salt in the solution = ?

Solution:

Since we have been given the concentration of the salt in the solution, we can use it to solve the problem.

Concentration; 15g/L

Given;

In 1L of the solution we have 15g of salt,

In 3.3L of the solution we will have 3.3 x 15 = 49.5g

The salt is the solute and it represents the dissolved substances.

learn more:

Concentration brainly.com/question/4641902

#learnwithBrainly

7 0

3 years ago

PLEASE HELP !! ILL GIVE BRAINLIEST !! 100 POINTS<br> IF YOU KNOW CHEMISTRY OR BIOLOGY

lys-0071 [83]

I am 100% positive it is C. Have a ice day ( ^ω^ )

5 0

3 years ago

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What are the subatomic particles of an atom, and where are they located in the atom? Be specific.

garri49 [273]

Answer:

120

Explanation:

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3 0

3 years ago