state the equation for the formation of ethane from its elements and ghen detwrmine the value for the standard enthalpy of formation of ethane
The standard enthalpy of formation of ethane is determined as -192.5 kJ/mol.
Reaction for the formation of ethaneThe reaction for the formation of ethane is given as;
2C + 3H₂ → C₂H₆
Where;
C is carbon (graphite)H is hydrogen C₂H₆ is ethaneStandard enthalpy of formation of ethaneThe standard enthalpy of formation of ethane is calculated as follows;
ΔH = ΔH₁ + ΔH₂ + ΔH₃
where;
ΔH₁ is heat of formation of graphite = -286 kJ/molΔH₂ is heat of formation of hydrogen = -393.5 kJ/molΔH₃ is heat of formation of ethane = 1560 kJ/mol2C + 3H₂ → C₂H₆
ΔH = 2(-286) + 3(-393.5) + 1(1560)
ΔH = -572 - 1180.5 + 1560
ΔH = -192.5 kJ/mol
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What determines an element's properties
Answer:
the atomic number
Explanation:
the atomic number/number of protons
7. What do all elements in the same period on the periodic table have in common?
They have the same number of orbitals.
They have the same number of neutrons.
They have the same number of electrons.
They have the same number of protons.
Answer:
they have same number of electrons
Which of the following is a combustion reaction?
a) 2KCIO3 → 2KCI + 302
b) 2 C4H10 + 13 O2 → 8 CO2 + 10 H2O
O
c) Fe + CuCl2 → FeCl2 + Cu
O
d) 4 Al + 3 O2 → 2 Al2O3
Answer:
D i guess..............
when a solid is dissolved in a liquid the vapor pressure of the liquid is blank because the surface area from which molecules can evaporate is reduced
when a solid is dissolved in a liquid the vapor pressure of the liquid is decreases because the surface area from which molecules can evaporate is reduced
What is Colligative properties of solution ?These are physical properties of solution that changes with the addition of solute , i.e. colligative properties are different for pure solvent and for solution which has solute .
those properties of a solution is a colligative property if it depends only on the ratio of the number of particles of solute and solvent in the solution, not the identity of the solute.
When a solute is added to the solvent, some of the solute molecules occupy the space near the surface of the liquid,
When a solute is dissolved in a solvent, the number of solvent molecules near the surface decreases, and the vapor pressure of the solvent decreases.
This has no effect on the rate at which solvent molecules in the gas phase condense to form a liquid.
But it decreases the rate at which the solvent molecules in the liquid can escape into the gas phase.
As a result, the vapor pressure of the solvent escaping from a solution should be smaller than the vapor pressure of the pure solvent.
Therefore when a solid is dissolved in a liquid the vapor pressure of the liquid is decreases because the surface area from which molecules can evaporate is reduced
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The table shows the results of a titration in which 25 cm3 of alkali were titrated with hydrochloric acid. Ignoring the anomalous result, calculate the mean volume of acid required to neutralise the alkali. Give your answer to 1 decimal place
Titration is used to describe a situation in which an acid is added slowly into a base to determine the amount of acid present.
What is titration?The term titration is used to describe a situation in which an acid is added slowly into a base and the amount of acid is determined from the volume of acid used.
We must note that the volume of acid is always the average volume of acid used and it can be used to compute the number of moles of acid. The question is incomplete as numerical values are not shown here.
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How to make slimy slime
Answer:
Combine shampoo and cornstarch in a bowl and mix well.
If desired, mix in 3-4 drops of food coloring.
Add in 1 tablespoon of water and stir. Stirring well after each, slowly add additional tablespoons of water.
Knead the slime for around 5 minutes.
Store in an airtight container.
Explanation:
1. To make slime at home, first place glue into a bowl, then add few drops of food coloring and stir until combined. Now add baking soda, stir it in.
2. After, knead or mix with a spoon for about 2-5 minutes until it turns into slime (patience is the key). Enjoy your homemade slime.
If a sealed, rigid container's pressure is doubled, what will happen to temperature?
Answer:
Temperature should double
Explanation:
Temperature and pressure are directly related given volume is held constant. If it's a rigid container, the volume is staying the same, thus increasing pressure will increase temperature.
I need a written report to explain how changing the conditions affects the rate of reaction. ( You may assume that an unnamed catalyst can be used in the reaction) Explain the factors affecting the rate of reaction.
Answer:
t4g35tgt
Explanation:
5yh45yh45
In an investigation, the atoms of a certain substance
lose energy during a change of state. Before the
change, the atoms are far apart and move constantly
at high speeds and in all directions. After the change,
the atoms are close together but are able to slide past
one another.
Use the diagram that shows changes of state between
solid, liquid, and gas to answer the question.
gas
M
M
zo
Z
Since the molecules tend to coalesce but still slide past one another, the substance was changed from gas to liquid.
What is a phase change?The term phase change refers to a change from one state of matter to another. Now we know that one of the effects of heat is a change of state.
Hence, when heat is withdrawn, the molecules tend to coalesce but still slide past one another. This implies that the substance was changed from gas to liquid.
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Answer: Choice 3: O
Explanation:
EDG FINAL
How do you know the correct number of significant figures to include in an answer?
Answer:
Explanation:
1 Non-zero digits are always significant.
2 Any zeros between two significant digits are significant.
3 A final zero or trailing zeros in the decimal portion ONLY are significant.
all the living and nonliving things in an specific area
Answer: An Ecosystem
Explanation:
One day while preparing dinner, Annie noticed something interesting. She
took two pots of water. In the first pot, she added one teaspoon of salt. In
the other pot, no salt was added. She set both pots on the stove and used a
thermometer to observe that the water with the salt boiled at a different
temperature than the water without the salt.
Given Annie's observation, write a possible hypothesis.
The water with the salt boiled at a higher temperature than the water without the salt.
What is elevation in boiling point?When we add any solute or other compound in any pure solvent then the boiling point of the solution will increases.
And elevation in boiling point will be expressed by the following equation:
ΔTb = (Kb)(m)(i), where
Kb = molal boiling point constantm = molalityi = Van't hoff factorSo the pot with salt will have higher boiling point then the simple water.
Hence, pot with salt has a higher boiling point.
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Ethanol is found to have a relative molecular mass of 46. If its molecular formula is C2HxOH. What is the value of X in the formula?
Answer:
The value of x in ethanol is 5
Explanation:
Given molar mass, you can subtract the molar masses of different elements present to find the missing amount of hydrogen; in other words:
Carbon*2 + Hydrogen*x + Oxygen*1 + Hydrogen*1 = 46
Molar mass carbon = 12.01
Molar mass hydrogen = 1
Molar mass oxygen = 16
12.01*2 g/mol + 1*x g/mol + 16*1 g/mol + 1*1 g/mol = 46 g/mol
Subtracting all knowns from the current molar mass gives
46 - 41.02 = 4.98
This means that x amounts of hydrogen has a molar mass of 4.98, or roughly just 5. Since each hydrogen has a molar mass of one, that means that there are 5 hydrogens missing and the complete molecular formula is C2H5OH
12) Which statement is not a component of the particle kinetic molecular theory of matter? A) Atoms of different elements are identical. B) Particles of matter have spaces between them. C) Particles of matter are constantly in motion. D) Atoms of the same element are essentially identical.
Answer:
c i got it right on usatestprep
Explanation:
............
Can you please help solve and explain the steps for the calculation?
The pH of a basic solution is 9.51, what is the [H+] ?
Answer:
The hydrogen ion concentration in a solution, [H+], in mol L-1, can be calculated if the pH of the solution is known.
pH is defined as the negative logarithm (to base 10) of the hydrogen ion concentration in mol L-1 pH = -log10[H+] ...
[H+] in mol L-1 can be calculated using the equation (formula): [H+] = 10-pH
Styrene glycol (C8H10O2) is a plasticizer. How many grams of styrene glycol must be dissolved in 98.7 g of benzene to raise the boiling point by 8.57 C? Kb for benzene is 2.67 C/m.
43.8 grams of styrene glycol must be dissolved in 98.7 g of benzene to raise the boiling point by 8.57 °C.
What is Boiling Point Elevation ?Boiling point elevation is the phenomenon that occurs when the boiling point of a liquid (a solvent) is increased when an another compound is added, such that the solution has a higher boiling point than the pure solvent.
Boiling point elevation occurs whenever a non-volatile solute is added to a pure solvent.
It can be calculated as
ΔT = i * [tex]K_{b}[/tex] * m
where m, Kb and i are the molality of solution, ebullioscopic constant and Van't Hoff factor respectively
The data given in the question is
ΔT = 8.57 °C
mass of solvent = 98.7 g
[tex]K_{b}[/tex] = 2.67 °C/m
Van't Hoff Factor for glycol is 1
Substituting the values in the above equation
8.57 = 1 * 2.67 * (moles of styrene glycol/mass of solvent in kg)
[tex]\rm \dfrac{8.57}{2.67} = \dfrac{moles}{98.7\;\times10^{-3} }\\\\\rmmoles \;of \;styrene\; glycol = \dfrac{8.57\times 98.7\times 10^{-3} }{2.67} \\\\\rm\dfrac{mass\; of\; styrene}{Molecular \;weight} = 0.3168\\\\\rmmass\; of\; styrene = 0.3168\times 138.2\\\\mass\; of\; styrene = 43.8 gm[/tex]
Therefore 43.8 grams of styrene glycol must be dissolved in 98.7 g of benzene to raise the boiling point by 8.57 °C.
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1. A gas having the following composition is burnt under a boiler with 50% excess air.
Component Mole%
CH4 70
C3H8 15
CO 15
What is the composition of the stack gas?
The composition of the stack gas are :
[tex]CH_4[/tex]= 0.8713
[tex]C_3H_8[/tex] = 0.0202
CO = 0.107
What is a mole fraction?The ratio of the number of moles of one component of a solution or other mixture to the total number of moles representing all of the components.
Assuming 100 g of the stack gas. Calculate the mass of each species in this sample according to their percentages.
Mass of [tex]CH_4[/tex] : 70% of 100 g = 70 g
Mass of [tex]C_3H_8[/tex] : 15% of 100 g = 15 g
Mass of CO : 15% of 100 g = 15 g
Now calculate the number of moles of each species:
Number of moles of [tex]CH_4[/tex] : [tex]\frac{70 g}{16.04 g/mol}[/tex] = 4.3 mole
Number of moles of [tex]C_3H_8[/tex]: [tex]\frac{15 g}{144.1 g/mol}[/tex] = 0.10 mole
Mass of CO : [tex]\frac{15 g}{28.01 g/mol}[/tex] = 0.53 mole
Now to calculate the mole fraction of each we use the formula:
Mole fraction of [tex]CH_4[/tex]: [tex]\frac{4.3}{4.935}[/tex] = 0.8713
Mole fraction of [tex]C_3H_8[/tex] : [tex]\frac{0.10}{4.935}[/tex] = 0.0202
Mole fraction of CO : [tex]\frac{0.53}{4.935}[/tex] = 0.107
Hence, composition of the stack gas are:
[tex]CH_4[/tex] = 0.8713
[tex]C_3H_8[/tex] = 0.0202
CO = 0.107
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How do molecular shape affect polarity
PLEASE HELP ME! do tectonic plates play a major or minor role in the ROCK CYCLE
i will choos e branliest
They react with water to form acidic solutions. HCI + H,O = HgO + C HF + H₂O H30* + F (i) Explain why water behaves as a base in both of these reactions?
Answer:
Explanation:
In both of these reactions, the water acts as an acceptor of hydrogen ions, and is thus a base.
What molarity should the stock solution be if you want to dilute 23.759 mL to 0.63 L and have the final concentration be 0.63 M?
M1.V1=M2V2
M1 x 23.759 = 0.63 x 0.63
M1 = 0.017 M
for the balanced equation: 2P + 3Br2 -> 2PBr2, how many moles of P reacted, if 0.175 moles of Br2 are produced
oxidation of Nitrogen in NO2
Explanation:
oxidation of Nitrogen in NO2 is +4
What is the volume of 300. g of mercury vapor at 822K and 0.900 atm?
Answer:
112.2L
Explanation:
Volume (V) = 300g
Temperature (T) = 822K
Pressure (P) = 0.9atm
using the ideal gas equation;
[tex]PV = nRT\\\\ V = \frac{nRT}{P}[/tex]
Molar gas constant (R) = [tex]0.0821L.atm/mol.K[/tex]
Mole (n) = [tex]\frac{Mass (m)}{Molar mass (M)}[/tex] Molar mass of Mercury = 200.59g/mol
[tex]n = \frac{300g}{200.59 g/mol} \\[/tex]
= 1.496mol
Now, the volume can be calculated;
V = [tex]\frac{1.496mol* 0.0821L.atm/mol.K*822K}{0.9atm}[/tex]
∴Volume of mercury = [tex]112.2L[/tex]
1. A recipe for s'mores calls for 2 graham crackers, 2 chocolate pieces and 1 marshmallow. If I
have 14 graham crackers, 20 chocolate pieces and 8 marshmallows. How many total s'mores can I
make? 2. Referring to question 57, how many ingredients of each type are leftover?
Please answer these 2 questions
Answer:
1. 7 , 2. 0 crackers, 6 choc pieces and 1 marshmallow
Explanatio
What is the main disadvantage to using overhead sprinklers, trench (furrow) irrigation, & flood
irrigation?
I will mark brainliest
Answer:
1. sovent
2. solute
3. solutability
Explanation:
A student hits a nail with a hammer. During the collision, there is _____.
Group of answer choices
a force on the hammer but not on the nail
a force on the nail but not on the hammer
a force on the nail and also on the hammer
no force on either object in the collision
Question 6
2 pts
The illustration shows all the forces in Newtons (N) acting on a box. The sum of all the
forces acting on the box results in a force acting on the box
5N
5N
O NF= 10 N balanced
O NF= 5N to the right
O NF= 0 Balanced
NF= 5N to the left
Answer:
Im pretty sure that 5N to the Right is correct answer
