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3 years ago

By using the following reactions, calculate the heat of combustion of pentane:

1 answer:

6 0

To answer this problem, we use Hess' Law to calculate the overall enthalpy of the reactions. The goal is to add all the reactions such that the final reaction is C<span>5H12 (g) + 8O2 (g) → 5CO2 (g) + 6H2O (l) through cancellation adn multiplication. The first equation is multiplied by 5, the second one is multiplied by 6 and the third one is reversed. The final answer is -3538 J or -3.54 x10^3 kJ.</span>

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4 molecules of glucose has how many carbon hydrogen and oxygen

gavmur [86]

Answer:

24 carbons

48 hydrogens

24 oxygen

Explanation:

7 0

3 years ago

3. All the following steps need to be followed when naming alkanes, except A. locating the longest carbon chain. B. using prefix

gulaghasi [49]

Answer:

D. beginning numbering at the end farther from the first branch.

Explanation:

In naming alkanes, the longest continuous chain in the compound is first considered and this gives the name of the compound intended. The name of the substituent on the compound are also arranged in alphabetical order when naming the compound.

The carbon atoms are numbered in the parent chain or ring to indicate where branching or substitution takes place. The direction of numbering is chosen such that the lowest numbers possible is given to the branches or substituents. If we begin the numbering at the end farther from the first branch, we won't give the lowest numbers possible to the branches.

8 0

3 years ago

Aqueous concentrated nitric acid is 69% hno3 by weight and has a density of 1.42 g/ml.

OleMash [197]

Answer: -

15.55 M

35.325 molal

Explanation: -

Let the volume of the solution be 1000 mL.

Density of nitric acid = 1.42 g/ mL

Total Mass of nitric acid Solution = Volume of nitric acid x Density of nitric acid

= 1000 mL x 1.42 g/ mL

= 1420 g.

Percentage of HNO₃ = 69%

Amount of HNO₃ = $\frac{69} {100} x 1420 g$

= 979.8 g

Molar mass of HNO₃ = 1 x 1 + 14 x 1 + 16 x 3 = 63 g /mol

Number of moles of HNO₃ = $\frac{979.8 g}{63 g/ mol}$

= 15.55 mol

Molarity is defined as number of moles per 1000 mL

We had taken 1000 mL as volume and found it to contain 15.55 moles.

Molarity of HNO₃ = 15.55 M

Mass of water = Total mass of nitric acid solution - mass of nitric acid

= 1420 - 979.8

= 440.2 g

So we see that 440.2 g of water contains 15.55 moles of HNO₃

Molality is defined as number of moles of HNO₃ present per 1000 g of water.

Molality of HNO₃ = $\frac{15.55 x 1000}{440.2}$

= 35.325 molal

3 0

3 years ago

The space shuttle heats up during reentry. Which term best describes what is causing

Korvikt [17]

The answer is Velocity .

6 0

3 years ago

Each glucose molecule consists only of carbon, hydrogen, and oxygen atoms. If each molecule contains 53.3% oxygen and 6.7% hydro

MAVERICK [17]

53.3% + 6.7% = 60%, 100% - 60% = 40%. 40% of glucose is made of carbon. Since there are only three types of atoms in glucose, and the amount of hydrogen and oxygen is already given, this means that whatever percentage is left (40%) has to be carbon.

8 0

4 years ago