What do you need to measure the amount of energy in food

Answer:

3.011 × 10²³

Explanation:

Given data:

Mass of oxygen produced = 8.05 g

Molecules of water decomposed = ?

Solution:

Balance chemical equation:

2H₂O   →   2H₂  + O₂

Number of moles of oxygen produced:

Number of moles = mass/molar mass

Number of moles = 8.05 g/ 32 g/mol

Number of moles = 0.25 mol

Now we will compare the moles of water with oxygen.

              O₂             :             H₂O

               1               :               2

              0.25         :            2×0.25 =0.5 mol

0.5 moles of water were decomposed.

Molecules of water decomposed:

1 mole = 6.022× 10²³ molecules of water

0.5 mol ×6.022× 10²³ molecules of water/ 1mol

3.011 × 10²³ molecules of water

Answer:

Heat needed to increase the temperature by 50°C is 94 j.

Explanation:

Given data:

Specific heat of silver = 0.235 j/g.°C

Heat needed to increase temperature = ?

Mass of silver = 8 g

Temperature difference = ΔT= 50°C

Solution:

Formula:

q = mcΔT

c = specific heat capacity of substance

Now we will put the values i formula.

q = 8 g× 0.235 J/g.°C× 50°C

q = 94 J

Heat needed to increase the temperature by 50°C is 94 j.

Answer:

Explanation:

Silk and wool

Answer:

silk and wool fibers are obtained from animals ​

Explanation:

good luck :)

Answer:

D

Explanation:

Because i just added all of numbers up

C. 24 if the zero after the 6H, is supposed to be a zero however if it wasnt and u were trying to say h2o it'd be 36

Answer:

second energy level

Explanation:

Valence electrons are those electrons which are present in outer most orbital of the atom.

This can be easily found through the electronic configuration of atom.

Electronic configuration of F:

F₉ = 1s² 2s² 2p⁵

We can see that the valence electrons are present in second energy level of F atom.

There are seven valence electrons of fluorine.

It is called halogens.

Halogens are very reactive these elements can not be found free in nature. Their boiling points also increases down the group which changes their physical states. i.e fluorine is gas while iodine is solid.

Fluorine:

1. it is yellow in color.

2. it is flammable gas.

3. it is highly corrosive.

4. fluorine has pungent smell.

5. its reactions with all other elements are very vigorous except neon, oxygen, krypton and helium.  

Answer:

5

Explanation:

According to this question, the chemical reaction is between Cobalt chloride (CoCl2) and sodium carbonate (Na2CO3) to produce Cobalt carbonate (CoCO3) and sodium chloride (NaCl).

The chemical equation is as follows:

CoCl2 + Na2CO3 ---> CoCO3 + NaCl

However, this equation is not balanced and needs to be with the use of coefficients. The balanced equation is:

CoCl2 + Na2CO3 ---> CoCO3 + 2NaCl

The sum of coefficients on the reactants side is 2 while the sum of coefficients on the product side is 3, hence, the total sum of all products and reactants is 5

In the balanced equation of the reaction of cobalt chloride and sodium carbonate reacting to form cobalt carbonate and sodium chloride, the sum of the coefficients for all the products and reactants is equal to 5.

A balanced equation is an equation for a chemical reaction in which the number of atoms for each element in the reaction and the total charge is the same for both the reactants and the products.

We will balance it using the trial and error method.

CoCl₂ + Na₂CO₃ ⇒ CoCO₃ + NaCl

We have 2 Cl atoms on the left and 1 Cl atom on the right. The same happens for Na. Thus, we can get the balanced equation by multiplying NaCl by 2.

CoCl₂ + Na₂CO₃ ⇒ CoCO₃ + 2 NaCl

The sum of the coefficients for all the products and reactants is:

1 + 1 + 1 + 2 = 5

In the balanced equation of the reaction of cobalt chloride and sodium carbonate reacting to form cobalt carbonate and sodium chloride, the sum of the coefficients for all the products and reactants is equal to 5.

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Answer:

5 cm³.

Explanation:

The following data were obtained from the question:

Volume of water = 35 mL

Volume of water + Rock = 40 mL

Volume of rock =.?

The volume of the rock can be obtained as follow:

Volume of rock = (Volume of water + Rock) – (Volume of water)

Volume of rock = 40 – 35

Volume of rock = 5 mL

Finally, we shall convert 5 mL to cm³. This can be obtained as illustrated below:

1 mL = 1 cm³

Therefore,

5 mL = 5 cm³

Thus, the volume of the rock is 5 cm³.

Answer:

C. Milk boils at about 212F

Explanation:

The principal constituents of milk are water, fat, proteins, lactose (milk sugar) and minerals (salts). Milk also contains trace amounts of other substances such as pigments, enzymes, vitamins, phospholipids (substances with fatlike properties), and gases.

Answer:The anwser is 5

Explanation:

Answer:

In carbon dioxide, on the right, there is 2.666 g of oxygen for every gram of carbon. So the ratio of oxygen in the two compounds is 1:2, a small whole number ratio

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Answer:

I need more context. Maybe add a picture.

Explanation:

Answer:

Crown B

Explanation:

because the density of gold is 19.3 and the density of the crown is 19.29.   

Answer:

Explanation:

H₂ , HCl , CH₃Cl , CH₂Cl₂ ----   Yes

CH₄  ------  No .

Symmetric molecules do not have rotational microwave absorption spectrum because they do not possess permanent dipole moment so they lack polarisability .

The pure rotational microwave absorption spectrum has been possessed by HCl and [tex]\rm \bold{CH_3Cl}[/tex].

Pure rotational microwave absorption has been consisted of the molecules having dipole and polarizability. The molecules that show the spectrum and dipole are diatomic molecules, linear molecules, spherical molecules.

(i) The hydrogen has been a diatomic molecule with symmetry thus not showing a pure rotational microwave absorption spectrum.

(ii) The HCl being a linear molecule possesses a pure rotational microwave absorption spectrum.

(iii) [tex]\rm CH_4[/tex] molecule has symmetry, thus will not possess a  pure rotational microwave absorption spectrum.

(iv) [tex]\rm CH_3Cl[/tex] molecule has no symmetry, and thus possesses a  pure rotational microwave absorption spectrum.

(v) [tex]\rm CH_2Cl_2[/tex] molecule with the presence of symmetry, thus lacks a pure rotational microwave absorption spectrum.

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Explanation:

It can be a demanding undertaking to reach adulthood as the offspring of mothers who immigrated to america. In the u.s, something many see as a land of opportunities relative to the world they left behind, parents frequently place heavy pressure on their kids to excel.

These same relatives can know only conjectural English, whereas their offspring rapidly become fluent, requiring the children to take on adult roles as parents need to connect with outside the environment of the family.

Answer:

[tex]m_{Cd(OH)_2}=36.6 gCd(OH)_2[/tex]

Explanation:

Hello.

In this case, for the given chemical reaction, in order to compute the grams of cadmium hydroxide that would be yielded, we must first identify the limiting reactant by computing the yielded moles of that same product, by 20.0 grams of NaOH (molar mass = 40 g/mol) and by 0.750 L of the 1.00-M solution of cadmium nitrate as shown below considering the 1:2:1 mole ratios respectively:

[tex]n_{Cd(OH)_2}^{by\ NaOH}=20.0gNaOH*\frac{1molNaOH}{40gNaOH} *\frac{1molCd(OH)_2}{2molNaOH} =0.25molCd(OH)_2\\\\n_{Cd(OH)_2}^{by\ Cd(NO_3)_2}=0.750L*1.00\frac{molCd(NO_3)_2}{L}*\frac{1molCd(OH)_2}{1molCd(NO_3)_2} =0.75molCd(OH)_2[/tex]

Thus, since 20.0 grams of NaOH yielded less of moles of cadmium hydroxide, NaOH is the limiting reactant, therefore the mass of cadmium hydroxide (molar mass = 146.4 g/mol) is:

[tex]m_{Cd(OH)_2}=0.25molCd(OH)_2*\frac{146.4gCd(OH)_2}{1molCd(OH)_2} \\\\m_{Cd(OH)_2}=36.6 gCd(OH)_2[/tex]

Best regards.

The mass of  Cd(OH)₂ that would be formed is 36.6 g

From the question,

We are to determine the mass of Cd(OH)₂ that would be formed

The given balanced chemical equation for the reaction is  

2NaOH(aq) + Cd(NO₃)₂(aq) → Cd(OH)₂ (s) + 2NaNO₃(aq)

This means

2 moles of NaOH reacts with 1 mole of Cd(NO₃)₂ to produce 1 mole of Cd(OH)₂ and 2 moles of NaNO₃

Now, we will determine the number of moles of each reactant present

Mass = 20.0 g

Molar mass = 39.997 g/mol

From the formula

[tex]Number\ of\ moles = \frac{Mass}{Molar\ mass}[/tex]

Number of moles of NaOH present = [tex]\frac{20.0}{39.997 }[/tex]

Number of moles of NaOH present = 0.50 mole

Volume = 0.750 L

Concentration = 1.00 M

From the formula

Number of moles = Concentration × Volume

∴ Number of moles of Cd(NO₃)₂ present = 1.00 × 0.750

Number of moles of Cd(NO₃)₂ present = 0.750 mole

Since,

2 moles of NaOH reacts with 1 mole of Cd(NO₃)₂

Then,

0.5 mole of NaOH will react with 0.25 mole of Cd(NO₃)₂

∴ The number of moles of Cd(NO₃)₂ that reacted is 0.25 mole

Now,

From the balanced chemical reaction

2 moles of NaOH reacts with 1 mole of Cd(NO₃)₂ to produce 1 mole of Cd(OH)₂

Then,

0.5 mole of NaOH will react with 0.25 mole of Cd(NO₃)₂ to produce 0.25 mole of Cd(OH)₂

∴ Number of moles of Cd(OH)₂ formed is 0.25 mole

Now, for the mass of Cd(OH)₂ that would be formed

From the formula

Mass = Number of moles × Molar mass

Molar mass of Cd(OH)₂ = 146.43 g/mol

∴Mass of Cd(OH)₂ formed = 0.25 × 146.43

Mass of Cd(OH)₂ formed = 36.6075 g

Mass of Cd(OH)₂ formed≅ 36.6 g

Hence, the mass of  Cd(OH)₂ that would be formed is 36.6 g

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Answer:

Explanation:

Half life of radioactive materials do not depend upon the mass of the material . It only depends upon the nature of radioactive materials . The half life of 20 g is 232 seconds . That means 20 gram will be reduced to 10 gram in 232 seconds .

Half life of 80 gram is also 232 seconds . So , 80 gram will be reduced to 40 gram in 232 second .

Answer:

A=element

B=compond

C=solution

Answer:

The elements in each group have the same number of electrons in the outer orbital. Those outer electrons are also called valence electrons. They are the electrons involved in chemical bonds with other elements. Every element in the first column (group one) has one electron in its outer shell.

Explanation:

I'm not really sure what the question is but I hope this helps.

Answer:

See explanation

Explanation:

A popular experiment that describes the effect of heat on the position of equilibrum is the change of colour when copper II chloride is heated.

As the solution is heated, it's colour changes from blue to green, this implies the the colour change (blue to green) is an endothermic process (equilibrum position shifts to the right with increase in temperature)

The equilibrum is represented by the equation;

[Cu(H2O)6]^2+(aq) + 4Cl^-(aq)<------>[CuCl4]^2-(aq) + 6H2O(l) ∆H=positive

The equilibrium mixture undergoing cooling or heating have colour changes. The temperature affects the colour of the products formed and the forward reaction is endothermic.

In the reaction copper (II) chloride or [tex]\rm CuCl_{4}[/tex] is the main species. The heat or the temperature affects the colour formation of copper (II) chloride as the equilibrium change affects the colouration of the product.

The heating of the solution affects the colour change from blue to the green of the reactant to products and the forward reaction shifts the equilibrium towards the right when the temperature is increased and is an endothermic reaction.

The reaction at the equilibrium can be shown as,

[tex]\rm [Cu(H_{2}O)_{6}]^{2+} (aq) + 4Cl^{-} (aq) \Leftrightarrow [CuCl_{4}]^{2-}(aq) + 6H_{2}O(l), \Delta H=positive[/tex]

Therefore, temperature changes the colouration and the forward reaction is an endothermic reaction.

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Answer:

F - O - S - Mg - Ba

Explanation:

as you move left to right on the periodic table the number of electrons increase.

The correct lists of the five atoms in order of increasing size smallest to

largest is :

D) F - O - S - Mg - Ba

The correct lists of the five atoms in order of increasing size smallest to

largest is F - O - S - Mg - Ba.

The atomic radius of a chemical element may be a degree of the measure of its molecule, as a rule the mean or commonplace remove from the center of the core to the furthest isolated electron.

The arrange will be:

As you move cleared out to right on the periodic table the number of electrons increment.

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Answer:

Explanation:

Molecular weight of barium sulphide = 169

500 mL of .192 M barium sulfide = .5 x .192 moles of barium sulphide

= .096 moles of barium sulfide

= .096 x 169 gram of barium sulfide

= 16.22 grams of barium sulfide .

We shall have to add 16.22 gram .

Answer:

Sulfur is characterized as a non-metal because it is consistent with the 3 physical properties listed for nonmetals. It is a poor conductor of heat and electricity because the electrons are not free to move.

Explanation:

2. Chemical formulas are used to describe the types of atoms and their numbers in an element or compound. The atoms of each element are represented by one or two different letters. When more than one atom of a specific element is found in a molecule, a subscript is used to indicate this in the chemical formula.

3. The main difference between monatomic and polyatomic ions is that monatomic ions are composed of single atoms whereas polyatomic ions are composed of two or more atoms per ion.

4. These are nonmetal elements which have accepted extra electrons. These ions are relatively few in number and are listed below. Monatomic anions are named by taking the root of the element name and applying an -ide ending. Other important simple anions.

5. This is indicated by assigning a Roman numeral after the metal. The Roman numeral denotes the charge and the oxidation state of the transition metal ion. For example, iron can form two common ions, Fe2+ and Fe3+. To distinguish the difference, Fe2+ would be named iron (II) and Fe3+ would be named iron (III).

Answer:

the answer to this question is c 140

Answer:

C. molten rock below Earth’s surface

Explanation:

Answer:

1.3x10⁻⁸ mol/L

Explanation:

0.0013μmol, Calculate concentration in mol/L

To obtain concentration in mol/L we need to convert the μmoles to moles and mL to liters:

Moles silver(II) oxide:

0.0013μmol × (1mol / 1x10⁶μmol) = 1.3x10⁻⁹ moles

Liters solution:

100mL * (1L / 1000mL) = 0.1L

That means concentration in mol/L is:

1.3x10⁻⁹ moles / 0.1L =

C=4

D=-19

Explanation:

2exp-25/5exp-7= 4exp-19

Answer:

3.48 x 1013 N2 molecules

step-by-step explanation:

Lets set up our equation first

P = 1.00 x 10-6 mm Hg T = 0.0° C + 273 = 273 K

We are given the V = 985 mL ,

R = 0.0821 L·atm/mol·K

Now use the ldeal gas law, but we are solving n, amount of substanvce

PV = nRT, we will change this equation to ;

n = PV/RT

n = 1.00 x 10-6 mm x 1 atm/760 mm x 985 mL x 1 L/103

mL/

(0.0821 L·atm/mol·K x 273 K) = 5.78 x 10-11 moles N2

nmolecules = 5.78 x 10-11 moles N2 x 6.02 x 1023 N2 molecules/1 mol N2