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lora16 [44]
3 years ago
12

Calculate the enthalpy of the formation of butane, C4H10, using the balanced chemical equation and the standard value below:

Chemistry
1 answer:
zavuch27 [327]3 years ago
6 0

Answer:

+125.4 KJmol-1

Explanation:

∆H C4H10(g) = -2877.6kJ/mol

∆H C(s)=-393.5kJ/mol

∆H H2(g) = -285.8

∆H reaction= ∆Hproducts - ∆H reactants

∆H reaction= (-2877.6kJ/mol) - [4(-393.5kJ/mol) +5(-285.8)]

∆H reaction= +125.4 KJmol-1

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Bogdan [553]
Matter can only me transformed, but not created or destroyed.
8 0
3 years ago
Read 2 more answers
NEED HELP ASAP ITS DUE TODAY THESE QUESTIONS
beks73 [17]

1.

Density can be defined as the mass of the substance in unit volume.

Density = mass / volume

Hence, g/mL and kg/L can be used as the units of density.

Those units are interchangeable because when converting one unit into other one nothing will happen to the value.

That is because when converting the g into kg, you have to multiply the value by 1 x 10⁻³. When converting mL into L, you should again multiply the volume by 1 x 10⁻³. Then those 1 x 10⁻³ will cancel off and the original value will remain as same.

2.

Answer is 2.70 g/mL.

<em>Explanation;</em>

Mass of the block = 146 g

Volume of the block =  length x width x height

                                  = 6.0 cm x 3.0 cm x 3.0 cm

                                  = 54 cm³ = 54 mL

Density = mass / volume

            = 146 g / 54 mL

            = 2.70 g/mL

3.

Answer is  3.39 g/mL.

<em>Explanation;</em>

When immersing an object in a solution, the increased volume indicates the volume of that object.

Hence,

  Volume of the object = increased volume of water level

                                      = final volume - initial volume

                                      = 27.8 mL - 21.2 mL

                                      = 6.6 mL

Mass of the object = 22.4 g

Density = Mass / Volume

            = 22.4 g / 6.6 mL

            = 3.39 g/mL

4.

Accepted value is the value that scientists and community accept as true. This is a theoretical value.

But the measured value is the value that you obtain from doing experiments. This is the actual value.

If your measured value is more close to the accepted value, then your measured value is more precise. But, if your measured value is far away from accepted value means that your value is not precise and there may have some errors.

5.

Answers : Percent error is 9.11 %

                 The element which has 7.13 g/cm³ as density is Zinc (Zn).

<em>Explanation;</em>

Percent error can be calculated by using following formula.

% error = ( (measured value - accepted value) / accepted value ) x 100%

            = ( (7.78 g/cm³ - 7.13 g/cm³) / 7.13 g/cm³ ) x 100%

            = 9.11 %

6 0
3 years ago
For the following example, list the given and unknown information (including gratis or moles)
Setler79 [48]

Answer:

9.6 moles O2

Explanation:

I'll assume it is 345 grams, not gratis, of water.  Hydrogen's molar mass is 1.01, not 101.

The molar mass of water is 18.0 grams/mole.

Therefore:  (345g)/(18.0 g/mole) = 19.17 or 19.2 moles water (3 sig figs).

The balanced equation states that:  2H20 ⇒ 2H2 +02

It promises that we'll get 1 mole of oxygen for every 2 moles of H2O, a molar ratio of 1/2.

get (1 mole O2/2 moles H2O)*(19.2 moles H2O) or 9.6 moles O2

6 0
2 years ago
how do you know the state of a compound when writing out the equation. WILL MARK BRAINLIEST PLEASE HELP!!
tester [92]

Answer:

The state of matter of each compound or molecule is indicated in subscript next to the compound by an abbreviation in parentheses. For example, a compound in the gas state would be indicated by (g), solid (s), liquid (l), and aqueous (aq).

Explanation:

3 0
3 years ago
A solution is made by dissolving 0.0150 mol of HF in enough water to make 1.00 L of solution. At 26 °C, the osmotic pressure of
Alex777 [14]
Given:
M = 0.0150 mol/L HF solution
T = 26°C = 299.15 K
π = 0.449 atm

Required:
percent ionization

Solution:
First, we get the van't Hoff factor using this equation:
π = i MRT
0.449 atm = i (0.0150 mol/L) (0.08206 L atm / mol K) (299.15 K)
i = 1.219367

Next, calculate the concentration of the ions and the acid.
We let x = [H+] = [F-]
[HF] = 0.0150 - x

Adding all the concentration and equating to iM
x +x + 0.0150 - x = <span>1.219367 (0.0150)
x = 3.2905 x 10^-3

percent dissociation = (x/M) (100) = (3.2905 x 10-3/0.0150) (100) = 21.94%

Also,
percent dissociation = (i -1) (100) = (</span><span>1.219367 * 1) (100) = 21.94%</span>
7 0
3 years ago
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