How much energy has your body used, in joules, if your health indicates the 450 Calories were burned during your workout? How many Calories are in a dinner containing 3.5 x 106 joules?

Answer:

33600 J

Explanation:

From the question,

ΔH = cm(t₂-t₁)..................... Equation 1

Where, ΔH = Enthalpy change of water, c = specific heat capacity of water, m = mass of water, t₂ = Final temperature of water, t₁ = Initial temperature of water

Given: c = 4200 J/kg.°C, m = 100 g = 0.1 kg, t₂ = 50°C, t₁ = -30°C

Substitute these values into equation 1

ΔH = 4200(0.1)(50+30)

ΔH = 420(80)

ΔH = 33600 J

Answer:

13.44 dm³ of hydrogen is needed for the reaction.

(D) is correct option

Explanation:

Given that,

Mass of  copper(II) oxide = 47.7 g

We know that,

Molar mass of CuO = 63.5 + 16 = 79.5 g/mol

We need to calculate the number of moles in 47.7g of copper(II) oxide,

Using formula of moles

[tex]mole=\dfrac{mass}{molar\ mass}[/tex]

Put the value into the formula

[tex]moles=\dfrac{47.7}{79.5}[/tex]

[tex]moles=0.6\ mole[/tex]

Now, we write the balanced equation for the reaction

[tex]CuO+H_{2}\Rightarrow Cu+H_{2}O[/tex]

Here, one mole of CuO reacted with one mole of hydrogen to produce one mole of Cu and one mole of water.

We need to calculate the number of moles of hydrogen needed to react  with 0.6 mole of copper(II) oxide

Using the balanced equation,

1 mole of CuO reacted with 1 mole of Hydrogen.

Therefore, 0.6 mole of CuO will also react with 0.6 mole of hydrogen.

We need to calculate the volume of  occupied by 0.6 mole of H2 at STP

Using formula of volume

[tex]n=\dfrac{V}{V'}[/tex]

Where, n = mole of hydrogen

V = occupied volume

V'= volume at STP

Put the value into the formula

[tex]0.6=\dfrac{V}{22.4}[/tex]

[tex]V=0.6\times22.4[/tex]

[tex]V=13.44\ dm^3[/tex]

Hence, 13.44 dm³ of hydrogen is needed for the reaction.

Answer:

NH3

Explanation:

A hydrogen bond donor is the supplier of the hydrogen atom that is involved in the hydrogen bonding interaction.

A hydrogen bond acceptor is the electronegative atom that 'accepts' the hydrogen in the hydrogen bond. Such electronegative atoms usually possess an unshared pair of electrons such as nitrogen.

We can see from the above definitions that NH3 is able to act in the capacity of a hydrogen bond donor(due to the presence of three N-H bonds) or as a hydrogen bond donor due to presence of an unshared pair on nitrogen atom.

Answer:

a. O₂ is limiting reactant

b. 5.68g P₄O₁₀ are produced

c. 5.83g P₄O₆ are left in the reaction container

Explanation:

Based in the first reaction,

P₄ + 3O₂ → P₄O₆

1 mole of P₄ reacts with 3 moles of oxygen

Initial moles of P₄ and O₂ are:

Moles P₄ (Molar mass: 124g/mol):

5.77g P₄ * (1mol / 124g) = 0.0465 moles P₄

Moles O₂ (32g/mol):

5.77g O₂ * (1mol / 32g) = 0.180 moles O₂

For a complete reaction of 0.0465 moles P₄ are required:

0.0465 moles P₄ * (3 moles O₂ / 1 mol P₄) = 0.140 moles of O₂

That means will remain 0.040 moles of O₂ and there are produced 0.0465 moles of P₄O₆

For the second reaction:

P₄O₆ + 2O₂ → P₄O₁₀

2 moles of oxygen reacts per mole of P₄O₆

For a complete reaction of P₄O₆ are required:

0.0465 moles P₄O₆ * (2 moles O₂ / 1mol P₄O₆) = 0.093 moles of O₂. As there are just 0.040 moles of O₂,

b. There are produced:

0.040 moles O₂ * (1 mole P₄O₁₀ / 2 moles O₂) = 0.020 moles P₄O₁₀

In mass (Molar mass: 284g/mol):

0.020 moles * (284g / mol) =

c. Also, 0.020 moles P₄O₆ are reacting and will remain:

0.0465 mol - 0.020 mol = 0.0265 moles P₄O₆

In mass (Molar mass: 220g/mol):

0.0265 moles P₄O₆ * (220g / mol) =

Answer:

The water/alcohol solvent caused the dots to move the most. The oil solvent

Explanation:

Answer:

Coarse and fine adjustment The coarse adjustment knob should only be used with the lowest powerobjective lens. Once it is in focus, you will only need to use the fine focus. Using the coarse focus withhigher lenses may result in crashing the lens into the slide.

Answer:

If Jerome is swinging on a rope and transferring energy from gravitational potential energy to kinetic energy,work is being done. Work is said to be done when it transforms energy from one form to another or from one place to another.

Explanation:

Answer:

Sounds great

Explanation:

Probably fake but you never know do you

Answer:

[See Below]

Explanation:

23 or 23.5 ml.

Answer:

105 mg

Explanation:

The following data were obtained from the question:

Original amount (N₀) = 420 mg

Half life (t½) =20 days

Time (t) = 40 days

Amount remaining (N) =..?

Next, we shall determine the rate constant K, for the disintegration.

This can be obtained as follow:

Half life (t½) =20 days

Rate constant (K) =?

K = 0.693/ t½

K = 0.693/20

K = 0.03465 /day

Finally, we shall determine the amount remaining after 40 days as follow:

Original amount (N₀) = 420 mg

Rate constant (K) = 0.03465 /day

Time (t) = 40 days

Amount remaining (N) =..?

Log(N₀/N) = kt/2.3

Log (420/N) = (0.03465 x 40)/2.3

Log (420/N) = 1.386/2.3

Log (420/N) = 0.6026

420/N = antilog (0.6026)

420/N = 4

Cross multiply

420 = N x 4

Divide both side by 4

N = 420/4

N = 105 mg

Therefore, the amount remaining after 40 days is 105 mg.

Answer:

trigonal pyramidal

Explanation:

There are two characteristics of molecules, one is geometry and other is shape. Shape is excluding lone pair surrounding the central element and geometry is including the lone pair. Therefore, the  word or two-word phrase best describes the shape of the phosphorus trifluoride ( PF[tex]_3[/tex]) molecule is trigonal pyramidal.

VSEPR stands for valence shell electron pair repulsions. VSEPR theory is used to predict the shape and geometry of molecules on the basis of valence electrons pairs that are present around the central element of the molecule.

According to VSEPR theory, Lone pair lone pair repulsion is greater than bond pair bond pair repulsion. There are so many limitations of VSEPR theory. There is a repulsion between bond pair electrons and lone pairs present on the central element. The  word or two-word phrase best describes the shape of the phosphorus trifluoride ( PF[tex]_3[/tex]) molecule is trigonal pyramidal.

Therefore, the  word or two-word phrase best describes the shape of the phosphorus trifluoride ( PF[tex]_3[/tex]) molecule is trigonal pyramidal.

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Answer:

A They are attracted to a magnet

Answer:

not sure but I think it's c

Answer:

Metaphase - this is when the chromosomes align

During Metaphase of mitosis, the chomosomes align at the middle part of the cell. Henc ethe correct option is (C).

In cell biology, mitosis is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei.

Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintained. Therefore, mitosis is also known as equational division.

During metaphase, the nucleus dissolves and the cell's chromosomes condense and move together, aligning in the center of the dividing cell.

At this stage, the chromosomes are distinguishable when viewed through a microscope.

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Explanation:

A gas has a temperature of 273.15 K and a pressure of 101.325 kPa. It can be concluded that this gas has reached standard temperature and pressure.

Standard temperature is zero degree celcius which corresponds to 273.15 degree kelvin.

Standard pressure is 760 mmHg which corresponds to 101.325 kPa.

Answer:

a. it has reached standard temperature and pressure

Explanation:

edge 2021

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Answer:

True

Explanation:

The correct option is; True.

Unimolecular elementary steps in a reaction requires only one reactants, they are usually decomposition reactions. They take the general form;

A --> B + C

Answer:

Uranium must be purified before it is used as a fuel source

Explanation:

The purer the uranium sample, the more the concentration of uranium in the fuel is.

Whenever uranium is extracted from nature, it contains a lot of impurities. Only a few special nuclear reactors can utilize uranium in this raw state. most of the others have to get uranium to become about 3% pure before they begin using it.

To do this, uranium has to be passed through a series of chemical reactions all with the aim of extracting the other compounds that may be present in the fuel.

Answer:

[tex]pH=3.95[/tex]

Explanation:

Hello,

In this case, by using the Henderson-Hasselbach equation we can compute the pH as follows:

[tex]pH=pKa+log(\frac{[base]}{[acid]} )[/tex]

Whereas the concentration of the acid (HCNO) and the base (NaCNO) are computed by considering the given volume:

[tex][base]=\frac{0.410mol}{2.0L}=0.205M[/tex]

[tex][acid]=\frac{0.130mol}{2.0L}=0.065M[/tex]

Therefore, the pH turns out:

[tex]pH=-log(3.5x10^{-4})+log(\frac{0.205M}{0.065M} )\\\\pH=3.95[/tex]

Regards.

Explanation:

a) Corrosive and b) Reacts with certain metals

Answer:

The answer to your question is "Displacement " reaction. Here in the reach Zn +HCl ⇒ZnCl2 + H2 zinc replaces the hydrogen to make the zinc chloride and hydrogen gas is produced as the result and liberated.

The question is incomplete, the complete question is;

Which is most closely associated with the Lewis dot diagrams for molecules that contain atoms of elements from the boron family, Group 13 (Group IIIA)?

a. elements shown as 3+ ions

b. expanded octets of electrons

c. incomplete octets of electrons

d. odd number of valence electrons

e. kernel electrons promoted to the valance shell

Answer:

incomplete octets of electrons

Explanation:

A Lewis dot structure is a representation of a molecule based on the number of valence electrons on its valence shell. These electrons are shown as dots hence Lewis structures are also called dot electron structures.

For elements of group 13, they mostly form dimeric compounds due to the fact that their compounds possess an incomplete octet of electrons. This is common to group 13 elements, hence the answer above.

Answer:

Explanation:

The composition of the vapor in mass percent.

According to Dalton's law,

where  is the partial pressure of the gas j,  is the mole fraction of the gas j in the gas mixture and  is the total pressure.

To know the composition of the vapor we must first calculate the molar fractions of the components of the mixture in the vapor:

→  

 →  

If we consider 1 mole of solution then we will have 0.56 mol of benzene and 0.44 mol of toluene in the vapor. In this way, the number of grams of each component in the vapor will be,

The percentage by mass of each component in the vapor will be,

% benzene = (g benzene / g total) x 100% = (43.7 g / (43.7 g + 40.6 g)) x 100% → % benzene = 51.8 %

% toluene = 100 % - % benzene → % toluene = 41.2%

So, the composition of the vapor in mass percent is 51.8 % benzene and 41.2% toluene.

Why is the composition of the vapor different from the composition of the solution?

The composition of the vapor will be different from that of the solution, since the more volatile compound will have a larger molar fraction in the vapor phase than in the liquid phase.

In a mixture with different volatile components the compound that volatilizes more easily is the one that will have greater capacity to escape from the solution in the form of vapor and, therefore, will be in a greater composition in the vapor above the solution.

We can measure this by means of vapor pressure, which is a measure of the volatility of a substance, that is, the capacity of the substance to pass from a liquid to a gaseous state. In the question, benzene is in greater proportion than toluene in the vapor mixture since it has a higher vapor pressure (94.2 torr) than toluene (28.4 torr).

Answer:

The answer is Option A = CCl2F2

The chemical formula for an organic molecule is CCl2F2. The correct option is A.

An organic molecule is a complicated compound that is chiefly comprised of carbon atoms bonded with other elements and another carbon atoms.

All lifeforms on Earth are comprised of organic molecules. A molecule is a cluster of atoms which are basically bonded together.

Molecules other than organic molecules is referred to as inorganic molecule. These are basically simple and are not usually encountered in living things.

Although all organic substances encompasses carbon, some substances containing carbon, such as diamonds, are taken as inorganic.

Organic compounds as well as inorganic compounds develops the basis of chemistry.

The chief distinction between organic and inorganic compounds is that organic compounds always contain carbon while most inorganic compounds do not encompass carbon.

Also, perhaps all organic compounds contain carbon-hydrogen or C-H bonds.

Thus, the correct option is A.

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Answer:

See explanation

Explanation:

XeF4 has a square planar structure. There are six electron pairs on the valence shell of the central atom. This gives rise to an octahedral geometry based on valence shell electron pair repulsion theory.

There are two lone pairs of electrons present on the central atom, hence the four bond pairs are found to occupy the corners of a square thereby giving a square planar compound. The two lone pairs are found above and blow the plane of the square.

Answer:

Hey!

39 / 24.2 = 943.8

Explanation:

943.8 to 2 s.f (best option for rounding)

= 940

ANSWER = 940

HOPE THIS HELPS!

Answer:

148.04 kJ/mol

Explanation:

Let's consider the following thermochemical equation.

NO(g) + 1/2 O₂(g) → NO₂(g)      ΔH°rxn = -114.14 kJ/mol

We can find the standard enthalpy of formation (ΔH°f) of NO(g) using the following expression.

ΔH°rxn = 1 mol × ΔH°f(NO₂(g)) - 1 mol × ΔH°f(NO(g)) - 1/2 mol × ΔH°f(O₂(g))

ΔH°f(NO(g)) = 1 mol × ΔH°f(NO₂(g)) - ΔH°rxn - 1/2 mol × ΔH°f(O₂(g)) / 1 mol

ΔH°f(NO(g)) = 1 mol × 33.90 kJ/mol - (-114.14 kJ) - 1/2 mol × 0 kJ/mol / 1 mol

ΔH°f(NO(g)) = 148.04 kJ/mol

Answer:

pH = 7.73

Explanation:

The pKa of the HOCl/KOCl buffer is 7.46. To determine the pH of this buffer we can use H-H equation:

pH = pKa + log [A⁻] / [HA]

pH = 7.46 + log [KOCl] / [HOCl]

Where [] is molarity -or moles- of each compound

Initial moles of HClO and NaClO:

HOCl: 0.500L * (0.12mol / L) = 0.06 moles HOCl

KOCl: 0.500L * (0.080mol / L) = 0.04 moles KOCl

Now, HOCl reacts with KOH producing KOCl:

HOCl + KOH → KOCl + H₂O

The moles of KOH in the reaction are:

2.5x10⁻³L * (10mol /L) = 0.025 moles KOH

That means after the reaction, 0.025 moles of HOCl are consumed and 0.025 moles of KOCl are produced.

And after the reaction, moles are:

Final moles:

HOCl: 0.06mol - 0.025mol = 0.035 mol

KOCl: 0.04mol + 0.025mol = 0.065 mol

Replaing in H-H equation:

pH = 7.46 + log [0.065mol] / [0.035mol]

Answer:

Explanation:

mass = 8.37 grams

volume = 23.1 - 20.0 = 3.1 mL

density = mass / volume

density = 8.37 / 3.10 = 2.70

Be sure and add the 0 in your answer. You have 3 places of significant digits.

Answer:

0.000399316  g

Explanation:

We can start with the molar fraction for each isotope:

We can say that the abudandance of [tex]^2^3Na[/tex] is an unknow value "X" and the molar fraction of [tex]^2^2Na[/tex] is "Y". We have to keep in mind that the molar fractions can be added:

Y + X = 1

So, we can put the molar fraction of [tex]^2^2Na[/tex] in terms of [tex]^2^3Na[/tex], so:

Y=1-X

So, we will have the molar fraction of each isotope:

[tex]^2^2Na[/tex]: X-1

[tex]^2^3Na[/tex]: X

And the atomic mass:

[tex]^2^2Na[/tex]: 21.9944

[tex]^2^3Na[/tex]: 22.9898

If we multiply the molar mass by the each atomic mass of each isotope we will have:

[tex] 22.9898*(X)~+~21.9944*(X-1)~=~22.9785[/tex]

Now we can solve for "X" :

[tex]22.9898X~+~21.9944X~-21.9944~=~22.9785[/tex]

[tex]44.9842X-21.9944~=~22.9785[/tex]

[tex]44.9842X~=~22.9785~+~21.9944 [/tex]

[tex]44.9842X~=~44.9729 [/tex]

[tex]X~=~\frac{44.9729}{44.9842}[/tex]

[tex]X~=~0.999749 [/tex]

The molar fraction of [tex]^2^3Na[/tex] is 0.999749. Now we can calculate the molar fraction of [tex]^2^2Na[/tex], so:

[tex]Y~=~1-0.999749~=~0.000251 [/tex]

Now, if we multiply the molar fraction by the mass we can find the mass of [tex]^2^2Na[/tex], so:

[tex]mass~of~^2^2Na~=~1.5909~g*0.000251~=~0.000399316~ g[/tex]

The mass of [tex]^2^2Na[/tex] is 0.000399316  g

I hope it helps!

Answer:the answer is hypothesis

Explanation: that’s the answer

Answer:

The volume of the rectangular prism is 77.616 cm³

Explanation:

Here is the remaining part of the question:

Part B:

What value should you use as the area of the base when calculating the answer to Part C.

Part C:

Using the correct answer from Part B, calculate the volume of a rectangular prism with a length of 5.6 cm , a width of 2.1 cm , and a height of 6.6 cm Part B answer: 11.76 cm^2

Explanation:

The volume of a rectangular prism is given by:

V = l×w×h

Where V is the volume of the rectangular prism

l is the length of the rectangular prism

and w is the width of the rectangular prism

Recall that the Area (A) of the base of the rectangular prism can be calculated by using

A = l × w

Hence, the volume of the rectangular prism can also be calculated by substituting this into the equation to give

V = A × h

From the question, the correct answer from part B for the area of the base is 11.76 cm^2; and the height (h) is 6.6 cm

Hence, the volume of the rectangular prism is

V = A × h

V = 11.76 cm² × 6.6 cm

V = 77.616 cm³