Number of atoms in 4.5 moles of Au?

Answer:

348.9 mL of the 60% solution and 251.1 mL of the 15% solution.

Explanation:

First, we calculate how many mililiters of pure carbonic acid are there in 650 mL of a 38% solution:

Then we can express the sum of both initial solutions as:

for the volume of carbonic acid; and

For the volume of the solutions.

We now have a system of two equations and two unknowns (x is the volume of the 60% solution and y is the volume of the 15% solution).

We express x in terms of y in equation 2):

And replace x in equation 1):

Finally we calculate x using equation 2):

Answer:

Explanation:

From the combustion of carbon, the reactions occurring in limited oxygen conditions are:

[tex]C(graphite) + \dfrac{1}{2}O_{2(g)} \to CO_{(g)}[/tex]  

[tex]C(graphite) + O_{2(g)} \to CO_{2(g)}[/tex]  

If it occurs in excess, then any leftover CO changes to CO2. i.e.

[tex]C(graphite) + O_{2(g)} \to CO_{2(g)}[/tex]   ---- (1)

[tex]CO_{(g)} + \dfrac{1}{2}O_{(g)} \to CO_{2(g)}[/tex]          ----- (2)

From (1), the enthalpy change is:

[tex]\Delta H_{rxn1} = \Delta H^0_{fCO_2(g)} - ( \Delta H^0_{f C(graphite)}+ \Delta H^0_{fCO_2(g)}[/tex]

[tex]\Delta H_{rxn1} =-393.5 \ kJ/mol -(0+0)[/tex]

[tex]\Delta H_{rxn1} =-393.5 \ kJ/mol[/tex]

From (2), the enthalpy change is:

[tex]\Delta_{rxn2} = \Delta H^0_{fCO_2(g)} - ( \Delta H^0_{fCO(g)} + \dfrac{1}{2} \Delta H^0_{fO_2(g)})[/tex]

[tex]\Delta_{rxn2} = -393.5 \ kJ/mol -(-110.5 + \dfrac{1}{2}(0))[/tex]

[tex]\Delta_{rxn2} = -283.0 \ kJ/mol[/tex]

Subtracting (2) from (1), we get:

[tex]C(graphite) + O_{2(g)} \to CO_{2(g)} \ \ \ \Delta H_{rxn} = -393.5 \ kJ/mol}[/tex]

[tex]CO_{(g)} + \dfrac{1}{2} O_2(g) \to CO_{2(g)}} \ \ \ \Delta H _{rxn2} = -283.0 \ kJ/mol[/tex]

[tex]C(graphite) + O_{2(g)} \to CO (g) + \dfrac{1}{2}O_{2(g)} \ \ \ \Delta H_{rxn} = -110.5 \ kJ/mol[/tex]

[tex]C(graphite) + \dfrac{1}{2} O_{2(g)} \to CO (g) \ \ \ \Delta H_{rxn} = -110.5 \ kJ/mol[/tex]

The enthalpy change ΔH of the reaction = -110.5 kJ/mol

Answer:

Mass

Explanation:

Answered this question multiple times and got it correct

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Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 9.033×10²³ is the number of molecules in 1.500 mole of H[tex]_2[/tex]O.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

Mathematically,

number of atoms/molecules=number of moles × 6.022×10²³(Avogadro number)

number of moles =1.500 mole

substituting all the given values in the above equation, we get

number of atoms/molecules=1.500  × 6.022×10²³(Avogadro number)

number of atoms/molecules =9.033×10²³molecules

Therefore, 9.033×10²³ is the number of molecules in 1.500 mole of H[tex]_2[/tex]O.

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Answer:

The coefficient of Z₂ is 1.

Explanation:

From the question given above:

X + ZY —> XY + Z₂

Next, we shall balance the equation to obtain the coefficient of Z₂. This can be obtained as follow:

X + ZY —> XY + Z₂

There is 1 atom of Z on the left side and 2 atoms on the right side. It can be balance by putting 2 in front of ZY as shown below:

X + 2ZY —> XY + Z₂

There are 2 atoms of Y on the left side and 1 atom on the right side. It can be balance by putting 2 in front of XY as shown below:

X + 2ZY —> 2XY + Z₂

Now, we have 1 atom of X on the left side and 2 atoms on the right side. It can be balance by putting 2 in front of X as shown below:

2X + 2ZY —> 2XY + Z₂

Now the equation is balanced.

Thus, the coefficient of Z₂ is 1.

The average atomic mass will be 3.70 amu

We have to obtain the average atomic mass by multiplying the mass of each isotope in amu by the relative abundance of the given isotope as contained in the data of the question.

Hence;

Average atomic mass;

(0.30 * 4) + (0.20 * 5) + (0.50 * 3)

= 1.20 + 1.00 + 1.50

= 3.70 amu

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Answer:

Two vectors are equal if they have the same magnitude and the same direction. Just like scalars which can have positive or negative values, vectors can also be positive or negative. A negative vector is a vector which points in the direction opposite to the reference positive direction.

Answer:

They are all mixture

Explanation:

last option

Answer:

Because the compound has a formula of M2O, the number of valence electrons of M should be 1. Therefore, (1) Group 1 is the correct answer because elements in group 1 have 1 valence electron.

Explanation:

Answer:

mass of HNO₃ = 0.378 g

Explanation:

Normality = Molarity * number of equivalents

Molarity = Normality/number of equivalents

normality of HNO₃ = 0.30 N, Volume = 20 mL

HNO₃ ionizes in the following way:

HNO₃(aq) ----> H⁺ + NO₃⁻

Therefore, number of equivalents for HNO₃ is 1

molarity of HNO₃ = 0.30/1 =0.30 mol/dm³

Using the formula, molarity = number of moles/volume in liters

number of moles = molarity * volume

Number of moles of HNO₃ = 0.30 mol/dm³ * 20ml * 1 dm³ /1000 mL

number of moles = 0.006 moles

From the formula, mass = number of moles * molar mass

molar mass of HNO₃ = 63.0 g/mol

mass = 0.006 * 63

mass of HNO₃ = 0.378 g

Answer:

6200 meters

Explanation:

To convert from km to m you have to multiply the number by a thousand

Answer:

6.2×10^3 m

Explanation:

6.20×1000=6200m

In scientific notation 6200 = 6.2×10^3

Answer:

The periodic law states “When elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties

Answer:

a. 1-fluoro-3,3,4-trimethyl-pentane.

b. 1-iodo-3-ethyl-2-methyl-hexane.

c. 1,3-dichloro-5-dimethyl-hexane.

d. 1-bromo-3-methyl-cyclopentane.

Explanation:

Hello!

In this case, according to the IUPAC rules for the listed alkyl halides, we first need to name the halogens (considering periodic order) then alkyl radicals and finally the parent chain; thus, the names are given below:

a. 1-fluoro-3,3,4-trimethyl-pentane.

b. 1-iodo-3-ethyl-2-methyl-hexane.

c. 1,3-dichloro-5-dimethyl-hexane.

d. 1-bromo-3-methyl-cyclopentane.

e. 5-chloro-1-bromo-1,1,5-trimethyl-pentane (radicals are not clear).

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Answer:

None have backbones

No cell walls

Multicellular

Includes radial or bilateral body symmetry.

Explanation:

Answer:

[tex]6K _{(s)} + N _{2(g)} = = > \:2K _{3} N _{(s)} [/tex]

Potassium nitride

Answer:

Non polar covlant

Explanation:

Answer: A chemical symbol is a one- or two-letter designation of an element. Compounds are combinations of two or more elements. A chemical formula is an expression that shows the elements in a compound and the relative proportions of those elements.

Answer and Explanation:

Since the compound sodium nitrate (NaNO₃) is a strong electrolyte, it dissociates completely into ions when is dissolved in water, as follows:

NaNO₃(s) → Na⁺(aq) + NO₃⁻(aq)

So, the solid compound produces the sodium cation (Na⁺) and the nitrate anion (NO₃-) in the aqueous medium.

Answer: metal and salt water

Explanation: salt starts to brake down metal and metal is everywhere in the ocean hope this helps

Answer:

baking a cake.

Explanation:

baking a cake is an example of a chemical reaction that happens daily because a new substance is forming when the cake is being baked. hope this helps! :)

Answer: The mole fraction of chloroform in this solution is 0.41

Explanation:

To calculate the moles, we use the equation:

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

a) moles of [tex]CHCl_3[/tex]

[tex]\text{Number of moles}=\frac{49g}{119g/mol}=0.41moles[/tex]

b) moles of [tex]CH_3COBr[/tex]

[tex]\text{Number of moles}=\frac{73g}{123g/mol}=0.59moles[/tex]

To calculate the mole fraction, we use the formula:

[tex]\text{Mole fraction of a component}=\frac{\text{Moles of the component}}{\text{total moles}}[/tex]

[tex]\text{Mole fraction of chloroform}=\frac{\text{Moles of chloroform}}{\text{total moles}}=\frac{0.41}{0.41+0.59}=0.41[/tex]

The mole fraction of chloroform in this solution is 0.41

Answer:

create a plan

the ways of of a student to set a goal

1. Write clear and measurable goals

2.Create a specific plan for each goal

3.Read your goals daily and visualize yourself accomplishing them

4. Reflect yourself to see if you are on target

5. Revise your action plans if needed.

1.)make a plan

2.)make a schedule

5.)pace him or herself

The question is incomplete, the complete question is;

The compound magnesium nitrate is a strong electrolyte. Write the reaction when magnesium nitrate is put into water:

Answer:

Mg(NO3)2(s)--------->Mg^2+(aq) + 2NO3^-(aq)

Explanation:

When we say that a compound is a strong electrolyte, we mean that that the compound dissociates completely in solution to form its ions.

This means that all strong electrolytes attain 100% dissociation of the solid in water according to its stoichiometric equation.

For magnesium nitrate, the reaction equation is;

Mg(NO3)2(s)--------->Mg^2+(aq) + 2NO3^-(aq)

Answer:

NO I DON'T ✌✌✌✌✌✌✌✌✌

When Silicone is altered with Phosphorus, 4 of its electrons form covalent bonding and the 5th electron becomes delocalized and thus it increases electrical conduction

Answer:

blue blah blue blah

Explanation:

Answer:

[tex]4.86\times10^{-7}\ \text{m}[/tex]

Explanation:

R = Rydberg constant = [tex]1.09677583\times 10^7\ \text{m}^{-1}[/tex]

[tex]n_1[/tex] = Principal quantum number of an energy level = 2

[tex]n_2[/tex] = Principal quantum number of an energy level for the atomic electron transition = 4

Wavelength is given by the Rydberg formula

[tex]\lambda^{-1}=R\left(\dfrac{1}{n_1^2}-\dfrac{1}{n_2^2}\right)\\\Rightarrow \lambda^{-1}=1.09677583\times 10^7\left(\dfrac{1}{2^2}-\dfrac{1}{4^2}\right)\\\Rightarrow \lambda=\left(1.09677583\times 10^7\left(\dfrac{1}{2^2}-\dfrac{1}{4^2}\right)\right)^{-1}\\\Rightarrow \lambda=4.86\times10^{-7}\ \text{m}[/tex]

The wavelength of the light emitted is [tex]4.86\times10^{-7}\ \text{m}[/tex].

The answer is A. The vibration caused by the waves through the air eventually weaken, which is why sound diminishes easily over distance.