What does a negative AHf for a molecule mean?
A. Energy was added when the molecule changed phases.
B. Energy was added when the molecule was formed from its
elements.
C. Energy was released when the molecule was formed from its
elements.
O D. Energy was released when the molecule went through a phase
change.
SUBMIT

Answers

Answer 1

Option D I got it right

Answer 2

ANSWER: C (ENERGY WAS RELEASED WHEN THE MOLECULE WAS FORMED FROM ITS ELEMENTS.)

HOPE THE OTHER PERSON IS WRONG!


Related Questions

the movement of carbon between the atmosphere, land, and ocean is called what?

Answers

The answer is the carbon cycle

As the temperature of a gas is increased, the
average kinetic energy of its molecules
A decreases
B. increases
Cremains the name

Answers

Answer:

B- Increase

Explanation:

In the event that the temperature is increased, the normal speed and dynamic energy of the gas atoms increment. In the event that the volume is held steady, the sped up the gas particles brings about more incessant and more powerful crashes with the dividers of the compartment, hence expanding the pressing factor

What happens when Sulphuric acid is added to into Barium Chloride solution?​

Answers

Answer:

please give me brainlist and follow

Explanation:

When dilute sulphuric acid is added to barium chloride solution, barium sulphate is formed as a precipitate and hydrogen chloride is formed in aqueous solution.



MRI machines use extremely strong magnetic fields. These fields must be adjustable to produce high-quality images. What might these
machines use to generate such a field?
A
electromagnets
B
permanent magnets
C
induced current

Answers

..................................
A

i need helpppp



blank 1:


blank 2:


blank 3:


blank 4:

Answers

Answer:

Fe₂(SO₄)₃ + 6KOH —> 3K₂SO₄ + 2Fe(OH)₃

The coefficients are: 1, 6, 3, 2

Explanation:

__Fe₂(SO₄)₃ + __KOH —> __K₂SO₄ + __Fe(OH)₃

To determine the correct coefficients, we shall balance the equation. This can be obtained as follow:

Fe₂(SO₄)₃ + KOH —> K₂SO₄ + Fe(OH)₃

There are 2 atoms of Fe on the left side and 1 atom on the right side. It can be balance by writing 2 before Fe(OH)₃ as shown below:

Fe₂(SO₄)₃ + KOH —> K₂SO₄ + 2Fe(OH)₃

There are 6 atoms of OH on the right side and 1 atom on the left side. It can be balance by writing 6 before KOH as shown below:

Fe₂(SO₄)₃ + 6KOH —> K₂SO₄ + 2Fe(OH)₃

There are 6 atoms of K on the left side and 2 atoms on the right side. It can be balance by writing 3 before K₂SO₄ as shown below:

Fe₂(SO₄)₃ + 6KOH —> 3K₂SO₄ + 2Fe(OH)₃

Now, the equation is balanced.

Therefore, the coefficients are: 1, 6, 3, 2

an equation thats shows how an objects acceleration relates to its mass

Answers

Answer:

Newton's second law of motion

F = ma

How do river systems, watersheds, and divides interact?

Answers

Answer:

They all end up in the oceon

Explanation:

Answer:

ok

Explanation:

i think they will all end up in ocean

Complete each nuclear reaction equation.

Superscript 14 subscript 7 upper N plus superscript 4 subscript 2 upper H e right arrow superscript question mark subscript 8 upper O plus superscript 1 subscript question upper H.

Nitrogen transmutes to form an isotope of oxygen. The superscript for oxygen is?

The subscript for hydrogen is?

Superscript 59 subscript question mark upper C o plus superscript 1 subscript 0 n right arrow superscript 60 subscript 27 upper C o.

Cobalt-59 accepts a neutron to form a new isotope. The subscript for cobalt is?

Answers

Nitrogen transmutes to form an isotope of oxygen. The superscript for oxygen is 17

The subscript for hydrogen is 1

Cobalt-59 accepts a neutron to form a new isotope. The subscript for cobalt is 27

Answer:

Oxygen = 17

Hydrogen = 1

Cobalt = 27

Explanation:

what types of chemical reactions are needed to make the perfect s'more?

Answers

Answer:

sorry i never learned this

Explanation:

Why or how, do electrons receive a positive charge during beta decay?

Answers

Answer: Beta decay occurs when a nucleus is unstable because it has too many or too few neutrons relative to protons. The nucleus emits a beta particle and energy.  In beta-minus decay, a neutron breaks down to a proton and an electron, and the electron is emitted from the nucleus.

Explanation:

Can someone please help me. Like right now please

Answers

Answer:

3rd law

Explanation:

when two objects interact, they apply forces to each other of equal magnitude and opposite direction.

How many poles does a magnet have?

Answers

A magnet has 2 poles

I'll give 50 pts and brainliest
Briefly explain the different types of mining and the processes!!

Answers

Answer:

Response is below

Explanation:

The different types of mining are underground, surface, placer, and in-situ. Underground mining uses various materials to excavate resources from beneath the surface of the Earth. Surface mining is a category of mining that in which soil and rock overlying the mineral deposit are removed. Placer mining is the mining of stream bed deposits for minerals. In-situ mining is a mining process used to recover minerals such as copper and uranium through boreholes drilled into a deposit.

Calculate the frequency in hertz of electromagnetic radiation that has a wavelength of 645.0 nm. (c = 3.00 X 10⁸ m/s)

Answers

Answer:

1/wavelength

c=1/alpha

which of the following statement is not a property of ionic compounds?
A. they are formed because of electrostatic forces.
B. they conduct electricity when dissolve in water
C. they form crystals
D. they have low melting and boiling points

Answers

Answer:

I think it would be c

Explanation:

PLEASE HELP ME!!!!! ILL GIVE BRAINLIEST

Answers

It would be the same

The topic of stoichiometry includes all of these except

Answers

Answer:

B

Explanation:

The answr is B..........

please help! What is the empirical formula for a compound that has 1 mole of nitrogen and 2.5 moles of oxygen?

Answers

Answer:

[tex]N_{2}O_{5}[/tex]

Explanation:

usually, the first step is to calculate the moles but since that is already given in the question we can move onto the next step

least molar ratio:

N = [tex]\frac{1}{1}[/tex] = 1

O = [tex]\frac{2.5}{1}[/tex] = 2.5

when the answer is in decimals we will multiply it by an integer in order to make it a whole number (in this case 2)

O = 2.5(2) = 5

in order to balance, we will also multiply the atoms of N by the same integer

N = 1(2) = 2

thus, the empirical formula is [tex]N_{2}O_{5}[/tex]

What is the total volume of solution that was dispensed from this burette?
A. 32.3 ml
B. 32.9 ml
C. 0.6 ml
D. 32.6 ml
E. 65.2 ml

Answers

Answer:

it will a i did the quiz got it all right

Explanation:

Describe the energy in nuclear fuel and the way in which it’s converted to electrical energy. Write 50 to 100 words.

Answers

Explanation:

You will have to rewrite this in your own words please. Download the app Paraphrase and also download Plagiarism Checker. Go on Paraphrase first and write it out then go to Plagiarism second and it'll tell you if you still need to reword it.

Answer:

A nuclear reactor produces electricity in much the same way other power plants do. The chain reaction produces the energy, which turns water into steam. The pressure of the steam turns a generator, which produces electricity.

Explanation:

Nuclear energy originates from the splitting of uranium atoms a process called fission. In nuclear fission, atoms are split apart to form smaller atoms, releasing energy. Fission takes place inside the reactor of a nuclear power plant. At the center of the reactor is the core, which contains uranium fuel. The uranium fuel is formed into ceramic pellets. Inside each uranium fuel pellet, there are millions of uranium nuclei. When these nuclei are split, a huge amount of energy is released. Some of this energy is from radiation, but the biggest source is kinetic energy. This is the energy that produces heat inside a reactor. The heat produced during nuclear fission in the reactor core is used to boil water into steam, which turns the blades of a steam turbine. As the turbine blades turn, they drive generators that make electricity. Nuclear plants cool the steam back into water in a separate structure at the power plant called a cooling tower, or they use water from ponds, rivers, or the ocean. The cooled water is then reused to produce steam.

Sarah is running a race and is almost to the finish line. In the last 5 seconds, her velocity changes from 2m/s to 4m/s. What is her average acceleration during the last 5 seconds of the race?

Answers

Answer:

[tex]\boxed {\boxed {\sf a= \frac {2}{5} \ or \ 0.4 \ m/s^2}}[/tex]

Explanation:

Acceleration is found by dividing the change in velocity by the time. The formula is:

[tex]a= \frac {v_f-v_i}{t}[/tex]

where [tex]v_f[/tex] is the final velocity, [tex]v_i[/tex] is the initial or starting velocity, and [tex]t[/tex] is the time.

Her velocity changes from 2 meters per second to 4 meters per second in the 5 seconds. Therefore:

[tex]v_f= 4 \ m/s \\v_i= 2 \ m/s \\t=5 \ s[/tex]

Substitute the values into the formula.

[tex]a= \frac { 4 \ m/s- 2 \ m/s}{5 \ s}[/tex]

Solve the numerator and subtract.

[tex]a= \frac { 2 \ m/s}{5 \ s}[/tex]

Divide.

[tex]a= \frac{2}{5} \ m/s/s= \frac{2}{5} \ m/s^2[/tex]

This can also be written as a decimal.

[tex]a=0.4 \ m/s^2[/tex]

Her average acceleration during the last 5 seconds of the race is 2/5 or 0.4 meters per square second.

Answer:

Solution :-

Here

Initial velocity = 2 m/s

Final velocity = 4 m/s

Time = 5 sec

v = u + at

4 = 2 + a(5)

4 - 2 = a(5)

2 = 5a

2/5 = a

Hence, acceleration is 2/5 m/s²

Approximately how many formula units of NaCl are in 116.88g of table salt (NaCl), knowing that the molar mass of NaCl is 58.44g/mol?

Answers

Answer:

116.88g of table salt (NaCl) contains two formula units

Explanation:

Now,

We know that 1 formula unit of sodium chloride has a molar mass of 58.44g/mol

Hence;

Mass of 1 formula unit = 58.44g

Mass of x formula units = 116.88g

x = 116.88g * 1 formula unit/58.44g

x = 2 formula units

Therefore;

116.88g of table salt (NaCl) contains two formula units

Answer:

There are  1.2044 × 10²⁴ formula units of NaCl in 116.88 g of table salt (NaCl)

Explanation:

A formula unit is an empirical formula of the smallest collection or number of atoms in an ionic or covalent combination from which a compounds formula can be established and which are used to represent the compound stoichiometrically

Sodium chloride is an ionic compound and is represented by the formula unit NaCl as it composed of ions and is not therefoe represented by a molecular formula

The given mass of the table salt, NaCl = 116.88 g

The molar mass of NaCl = 58.44 g/mol = The mass of 1 mole of NaCl

1 mole of NaCl contains one Avogadro's number or 6.022 × 10²³ formula units of NaCl,

∴ 58.44 g of NaCl contains 6.022 × 10²³ formula units of NaCl

116.88 g of NaCl will have (116.88/58.44) × 6.022 × 10²³ = 1.2044 × 10²⁴ formula units of NaCl

The number of formula units of NaCl in 116.88 g of table salt (NaCl) =  1.2044 × 10²⁴ formula units of NaCl.

Can you help me out with gravity study!?
Awnser 4 questions only please!

Answers

Answer:

F

T

F

T

Explanation:

i hope these are right

If 1.00L of water is added to 3.00 L
of a 6.00M solution of HCl, what is the
new molarity of the acid solution?

Answers

Answer:

4.5M

Explanation:

Here is why:

Please Help me with number 4 I really need help please just tell me which letter is

Answers

Answer:

i believe it's D

Explanation:

Answer:

D

Explanation:

what do elements and atoms have in common

Answers

Answer:

what they have in common is consist of electrons, protons, and neutrons.

Explanation:

describe the process of testing the pH of an unknown solution

Answers

A pH meter will make short work of identifying the pH of your solution. These meters have a glass probe that measures a solution's ion concentration. To use a pH meter, place a small portion of your solution in a beaker or test tube, rinse the probe of the pH meter, and then place the probe into your solution.

Source:

https://sciencing.com/identify-solution-neutral-base-acidic-8346.html

pH depend on the temperature. At room temperature pH scale is between 0 to 14. pH of neutral solution is 7. pH meter is the only instrument to measure the pH of an unknown solution.

What is pH?

pH is a measurement of amount of hydronium ion H₃O⁺ in a given sample. More the value of hydronium ion concentration, more will be the solution acidic.

On subtracting pH from 14, we get pOH which measures the concentration of hydroxide ion in a given solution.

pH meter is used to measure the pH of an unknown solution. A glass probe is attached to pH meters, that measure the concentration of hydrogen ion in unknown solution. Take the unknown solution in the beaker and then put the washed, clean glass probe in the solution. Now wait for a second to take the reading.

Therefore, pH meter is the only instrument to measure the pH of the solution.

To learn more about pH, here:

https://brainly.com/question/27945512

#SPJ2

A shampoo has a pH of 8.59. What is the [H3O+] in the shampoo?
Answer in units of M.

(part 2) What is the [OH−] in the shampoo?
Answer in units of M.

Answers

Answer:

2.57 e-9

Explanation:

The formula is H3O=10^-Ph

10^-8.59=2.57 e-9

Does Water gives the body the ability to do work. True or false

Answers

Answer:

I think it's true

Explanation:

hey by the way

7. A certain hydrocarbon, CxHy, is burned (reacts with O2 gas) and produces 1.955 g of CO2 for every
1.000 g of H20. What is the empirical formula of this hydrocarbon?
CxHy + (X + y/4) O2 -> xCO2 + y/2 H2O

Answers

Answer:

The empirical formula of the hydrocarbon is C₂H₅

Explanation:

The formula for the hydrocarbon is [tex]C_xH_y[/tex]

The mass of CO₂ produced per 1,000 g of H₂O = 1,955 g

The equation for the chemical reaction is given as follows;

[tex]C_xH_y[/tex] + (x + y/4) O₂ → XCO₂ + y/2H₂O

From the given chemical equation, counting the number of atoms on both sides of the equation, we have;

The molar mass of CO₂ = 44.01 g/mol

The molar mass of H₂O = 18.01528 g/mol

The number of moles of H₂O in 1,000 g of H₂O = 1,000 g/(18.01528 g/mol) = 55.5084351 moles

The number of moles of CO₂ in 1,955 g of H₂O = 1,955 g/(44.01 g/mol) = 44.4217223 moles

Therefore, given that X moles of CO₂ is produced alongside Y/2 moles of H₂O. we have;

X = 44.4217223, Y/2 = 55.5084351

∴ Y = 2 × 55.5084351 = 111.0168702

The ratio of X to Y = X/Y = 44.4217223/111.0168702 = 0.40013488238

∴ The ratio of X to Y = X/Y ≈ 0.4 = 4/10

X/Y ≈ 4/10

The empirical formula is the representation of molecular formula in the smallest whole number ratio of the elements of the molecules

Therefore, when X = 4, Y = 10, from which we have the smallest ratio as;

When X = 2, Y = 5

The empirical formula of the hydrocarbon is therefore, [tex]C_xH_y[/tex] = C₂H₅

The given chemical equation becomes;

C₂H₅ + (2 + 5/4) O₂ → 2CO₂ + 5/2H₂O

C₂H₅ + 3.25 O₂ → 2CO₂ + 2.5 H₂O

We then have;

4C₂H₅ + 13 O₂ → 8CO₂ + 10 H₂O

The empirical formula of the hydrocarbon, [tex]C_xH_y[/tex] = C₂H₅.

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