if the heat of combustion of hydrogen is -285.8KJ,what is the heat of formation of water​

Answers

Answer 1

Answer:

The heat of formation of H2O(g) is likely to be-242,8KJ.

Explanation:

The heat of formation of H2O(g) will be slightly lower than the heat of formation of H2O(1)as some energy is released during condensation of water vapour to liquid water.


Related Questions

intrusive igneous rock forms when the cooling of magma takes place fast on the top of the Earth's surface. A. True B. False

Answers

Answer:

A

Explanation:

True igneous rock forms cooling of magma fast on the top

Answer:

The answer is A. True

Explanation:

A balloon takes up 625 L at 0°C. If it is heated to 80°C, what will its new volume be?

Answers

Answer:

Me gusta tu corte G

Explanation:

A sample of gas has a volume of 2.0 liters at a pressure of
1.0 atmosphere. When the volume increases to 4.0 liters, at constant temperature, the pressure will be


a. 0.50 atm
b. 2.0 atm
c. 0.25 atm
d. 1.0 atm

Answers

x= 2.0atm when u substitute for V1P1=V2P2

HELP ASAP!!!
can someone help be determine the formulas for reactants and products as well as balance the equation, and what type of reaction is presented!!!!
I will make you the brain list!!!

Answers

Answer: owa owa

Explanation: owa owa owa owa

Pls, Answer ASAP!!!! I have to turn in my HW in 20 mins!!
In the rocket fuel formulation for NASA, 325 grams of solid aluminum (Al) particles are heated with 211 grams of solid iron III oxide (Fe2O3). Show all work and units. Include significant figures in your final answer.

a) Write the balanced equation
b) Calculate the mass of iron produced from the reaction
c) Identify the limiting reagent
d) Determine the amount of excess reactant leftover

Show all work and units. Include significant figures in your final answer.

Answers

Answer:

B. Calculate the mass of iron produced from the reaction

Explanation:

Sana makatulong mark me as a brainliest

The boiling point of a liquid is the temperature at which its ____________ _____________ is equal to ____________ ____________.(atmospheric pressure, vapor pressure

Answers

Answer:

vapor pressure, atmospheric pressure

Explanation:

the boiling point of a liquid is the temperature at which its vapor pressure is equal to the pressure of the gas above it.

(I'm not too sure if this is right but I think it is)

What phase change occurs when a solid changes into a gas?

Answers

Answer:

Sublimation

Explanation:

Sublimation is the term used to describe when a solid "skips" the liquid phase and turns directly into a gas from solid form. Dry ice demonstrates sublimation when exposed to room temperature air.

during the combustion of methane (CH4), one mole of methane gas combines with two moles of oxygen gas (O2) to produce one mole of carbon dioxide gas (CO2) and two moles of water vapor. Which of the following chemical equations correctly represents the combustion of methane described above?
a)CH4(g) + 2O(g) ↔ CO2(g) + 2H2O(g)
b)CH4(g) + 2O(g) ↔ CO(g) + 2H2O(l)
c)CH4(g) + 2O2(g) ↔ CO2(g) + 2H2O(g)
d)CH4(g) + 2O2(g) ↔ CO(g) + 2H2O(l)

Answers

Answer:

a) cH4(g) +2O(g)__ CO2(g) +2H2O(g)

I hope this help

Radiation from which type of decay has the least energy?
A. Electromagnetic decay
B. Beta decay
C. Alpha decay
D. Gamma decay
SUBMIT

Answers

Radiation from alpha decay has the least energy.

Alpha decay is the name for the nuclear process that releases alpha particles. Two protons that were lost by the uranium atom are present in the alpha particle. Additionally, the two protons have a +2 charge. The particle's mass, or the sum of its protons and neutrons, is represented by the top number, 4, in this case. Alpha particles must also have two neutrons because they have two protons, making a total of four protons and neutrons. Two protons and two neutrons are the constant components of alpha particles.

A nuclear process known as "alpha decay" releases a particle made up of two protons and two neutrons when an unstable nucleus transforms to another element. The helium nucleus that is being ejected is known as an alpha particle.

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Answer:

C) Alpha decay

Explanation:

Alpha decay, beta decay, electromagnetic decay, Gamma decay

its least to greatest

Identify the product(s) of the following reaction:
H
2
​2
​​ CO
3
​3
​​ → H
2
​2
​​ O + CO
2
​2
​​
A
H
2
​2
​​ CO
3
​3
​​
B
H
2
​2
​​ and O
3
​3
​​
C
H
2
​2
​​ O and CO
2
​2
​​
D
O and O
2
​2
​​

Answers

Answer:

H20

Explanation:

means water but might not help

What molecules would you expect to find in air

Answers

Answer:

The air in the atmosphere consists of nitrogen, oxygen, which is the life-sustaining substance for animals and humans, carbon dioxide, water vapour and small amounts of other elements (argon, neon, etc.). Higher in the atmosphere air also contains ozone, helium and hydrogen.

Explanation:

Answer:

nitrogen, oxygen, carbon dioxide, water vapour, ozone, helium, and hydrogen.

Explanation:

science question. Can you also tell me what weight has to do with the acceleration?

Answers

Box B will have a high acceleration. The less mass = more speed

which particle has the least mass
a. electron
b. proton
c. neutron
d. all have the same mass

Answers

Answer:

b. proton

Explanation:

The mass of an electron is only about 1/2000 the mass of a proton or neutron, so electrons contribute virtually nothing to the total mass of an atom. Electrons have an electric charge of −1, which is equal but opposite to the charge of a proton, which is +1.

How many particles are in 5.00 grams of nitric acid?

Answers

Answer:

0.0500

Explanation:

WHAT IS THE CHEMICAL REACTION

Answers

Answer:

hi

Explanation:

Chemical reactions are an integral part of technology, of culture, and indeed of life itself. Burning fuels, smelting iron, making glass and pottery, brewing beer, and making wine and cheese are among many examples of activities incorporating chemical reactions that have been known and used for thousands of years. Chemical reactions abound in the geology of Earth, in the atmosphere and oceans, and in a vast array of complicated processes that occur in all living systems.

-facts

write importance of magnesium metal​

Answers

Answer:

can be used in fireworks, flares and sparklers

Explanation:

as it burns in air it ignites with bright light

2 spaceships are in deep space. The distance between the centers of mass of the two spaceships is 300 m, and the force between them is 5.51×10^-7N. If one spaceship has a mass of 24,000 kg, what is the mass of the other spaceship?

Answers

Answer:

Mass of the second spaceship is 3.10 × 10⁴ kg 0r 31000 kg

Explanation:

From Newton's law of universal gravitation, the force of attraction , F, between two bodies is directly proportional to the product of their masses and inversely proportional to the square root of the distance between them.

F = Gm₁m₂/d²

m₁ = 24000 kg

m₂ = ?

d = 300 m

F = 5.51 × 10⁻⁷ N

Gravitational constant,  G = 6.67 × 10⁻¹¹ N.m²/kg²

Making m₂ subject of the formula : m₂ = F × d² / G × m₁

m₂ = 5.51 x 10⁻⁷ × 300 × 300 / 6.67 × 10⁻¹¹ × 24000

m₂ = 3.1 × 10⁴ kg

Therefore, Mass of the second spaceship is 31000 kg

If the energy of a photon of light is 3.37 x 10–19 J, what is the frequency of the light? A. 1.12 x 10–27 s –1 B. 8.90 x 1026 s –1 C. 5.09 x 1014 s –1 D. 6.70 x 10–44 s –1 E. 1.01 x 10–10 s –1

Answers

Answer:

The appropriate alternative is option C "[tex]5.09\times 10^{14} \ s[/tex]".

Explanation:

The given value is:

Energy of photon,

E = [tex]3.37\times 10^{-19} \ J[/tex]

As we know,

h = [tex]6.626\times 10^{-34} \ Js[/tex]

Now,

The frequency of the light will be:

⇒  [tex]E=hv[/tex]

On substituting the given values, we get

⇒  [tex]3.37\times 10^{-19}=6.626\times 10^{-34}\times v[/tex]

On solving, we get

⇒                    [tex]v=5.09\times 10^{14} \ s[/tex]

If the energy of a photon of light is 3.37 x 10⁻¹⁹ J, then the frequency of the light is 5.09 x 10¹⁴ per sec.

How we calculate frequency?

Frequency of light will be calculated by using the below formula:
E = hυ, where

E = energy of photon = 3.37 x 10⁻¹⁹ J

h = plank's constant = 6.626 × 10⁻³⁴ Js

Putting these values on the above equation and calculate for the frequency as:

υ = 3.37 x 10⁻¹⁹ J / 6.626 × 10⁻³⁴ Js = 5.09 x 10¹⁴ per sec

Hence, option (C) is correct i.e. 5.09 x 10¹⁴ per sec.

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5.25 ml of substance A has a mass of 3.9 g and 6.24 ml of substance B has a mass of 4.4 g. Which liquid is more dense?

Answers

Answer:

A is more dense

Explanation:

The is because you can find the density of anything by dividing the Mass by volume A is .7428 and B is .7051 . There fore A is denser .

What mitigation measures can communities do to reduce the damage and impact of sudden geologic hazards?

Answers

Explanation:

require an emergency support immediately

Which element is the first element in group 13 of the periodic table of elements?​

Answers

Answer:

Boron

Explanation:

Answer:

Boron

Explanation:

Boron is the first element of Group 13 and is the only metalloid of the group. Its chemical symbol is B, and it has an atomic number of 5. Boron has the electron configuration [He] 2s 2 2p 1 and prefers an oxidation state of +3. Boron has no natural elemental form; it forms compounds which are abundant in the Earth's crust.

if you help me, you are the best​

Answers

Answer:

The following numbers are true for protons:

2.

5.

7.

Explanation:

I know for a fact that Protons have a positive charge

they are located inside of the nucleus

Go.ogle says that they aren't involved in bonding

And it says that it has a mass of one

I hope this helps chu <3

how many molecules are in 2.1 moles of carbon monoxide

Answers

Answer:

[tex]1.26*10^2^4[/tex]

Explanation:

To find molecules, we will need to multiply the number of moles of carbon monoxide by Avogadro's number. Avogadro's number is [tex]6.022*10^2^3[/tex].

So the equation would look like this:

[tex](2.1) * (6.022*10^2^3) = 1.26 *10^2^4[/tex]

How are the four kinds of DNA nucleotides different from each other?

Answers

Answer:

The sugar in DNA is deoxyribose. ... Nucleotides in DNA contain four different nitrogenous bases: Thymine, Cytosine, Adenine, or Guanine. There are two groups of bases: Pyrimidines: Cytosine and Thymine each have a single six-member ring.

Adenine, Cytosine, Thymine, and Guanine are the four nucleotides that make up DNA. The four nucleotides have different base structures, but they are all composed of a nitrogenous base, a deoxyribose sugar, and a phosphate group.

What are nucleotides ?

Nucleotides are organic compounds made up of a phosphate and a nucleoside. They function as monomeric units of the deoxyribonucleic acid and ribonucleic acid polymers, which are both crucial macromolecules for all kinds of life on Earth.

Adenine, Cytosine, Thymine, and Guanine are the four nucleotides that make up DNA. The four nucleotides have different base structures, but they are all composed of a nitrogenous base, a deoxyribose sugar, and a phosphate group.

The quantity of phosphate residues that a nucleotide has determined its name. Adenosine triphosphate, for instance, is the name of a nucleotide that consists of an adenine base and three phosphate residues (ATP). Adenosine diphosphate would be the nucleotide if it has two phosphates (ADP).

Thus, Adenine, Cytosine, Thymine, and Guanine are the four nucleotides that make up DNA.

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When a predator population increases what happens to the prey population? Increase Decrease Dies Stays the same

Answers

Answer: as the number of predators increases, more prey are captured. as a result the prey population starts to decrease.

How do gut bacteria help people?(1 point)
A
by making enzymes to break down food
B
by causing a variety of digestive disorders
C
by releasing compounds that kill harmful bacteria
D
by training other bacteria to treat infection

Answers

Answer: the answer would be B

I think It’s A hope this helps

A company that is concerned about the environment wants to encourage the use of their fuel cell cars, so they are putting
together information to help sell the cars. They want to be sure their material is accurate. Which piece of information is
true about fuel cell cars?
O Fuel cell cars are cheaper to buy. Fuel cell cars reduce use of non-renewable fossil fuels
Fuel cell cars are more powerful than gasoline-powered vehicles.
Fuel cell cars allow for the safe storage of hydrogen gas at filling stations.

Answers

Fossil cell cars reduce use of non renewable fossil fuels.

Answer:

B. Fuel cell cars reduce use of non-renewable fossil fuels

Explanation:

Select ALL that apply.
What factors affect wave height?
Lesson 2.14

Fetch

Strength of wind

Direction of the wind

Duration of wind

Answers

The factors affect wave height is the duration of the wind

Answer:

all answers are correct

Fetch

Strength of wind

Direction of the wind

Duration of wind

Explanation:

i took the quiz hope this helps!

If a 60-g object has a volume of 30cm3 what is its density

Answers

Answer:

2 g/cm3

Explanation:

Density is a measure of a substance's mass over its volume.

d = m/v

Therefore d = 60g/30cm3 = 2 g/cm3

What is the molality of a solution containing 30.0 g of napthalalene (C10H8) dissolved in 500.0 g of toulene? Please provide work. Thanks in advance!

Answers

Answer:

0.468 m

Explanation:

From the question given above, the following data were obtained:

Mass of napthalalene (C₁₀H₈) = 30 g

Mass of toulene = 500 g

Molality =?

Next, we shall determine the number of mole in 30 g of C₁₀H₈. This can be obtained as follow:

Mass of C₁₀H₈ = 30 g

Molar mass of C₁₀H₈ = (12×10) + (8×1)

= 120 + 8

= 128 g/mol

Mole of C₁₀H₈ =?

Mole = mass / molar mass

Mole of C₁₀H₈ = 30 / 128

Mole of C₁₀H₈ = 0.234 mole

Next, we shall convert 500.0 g of toulene to Kg. This can be obtained as follow:

1000 g = 1 Kg

Therefore,

500 g = 500 g × 1 Kg / 1000 g

500 g = 0.5 Kg

Finally, we shall determine the molality of the solution. This can be obtained as follow:

Mole of solute (C₁₀H₈) = 0.234 mole

Mass of solvent (toulene) = 0.5 Kg

Molality =?

Molality = mole of solute / Kg of solvent

Molality = 0.234 / 0.5

Molality = 0.468 m

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