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2 years ago

A pure gold bar is made of 19.55 mol of gold. What is the mass of the bar in grams

Chemistry

2 answers:

Bogdan [553]2 years ago

8 0

19.55 x 196.97 =
3850.76

Law Incorporation [45]2 years ago

4 0

(19.55 mol Au) / ( 1 ) x (196.97 g Au) / ( 1 mol Au) =
19.55 x 196.97 =
3850.76 g Au

I hope this helps you and have a great day!! :)

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a carbon-12 atom has a mass defect of 0.9564 amu. what is its nuclear binding energy? round to 3 significant figures.

emmasim [6.3K]

Answer:

Explanation:

A carbon-12 atom has a mass defect of 0.09564 amu. What is its nuclear binding energy? Round to 3 significant figures. x 10 J per carbon-12 atom

First use the formula;

1 amu =934 MeV

therefore 0.09564 will have

934 x 934

= 89.3 MeV

7 0

2 years ago

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For each of the following substituents, indicate whether it withdraws electrons inductively, donates electrons by hyperconjugati

AveGali [126]

Answer:

a. withdraws electrons inductively

b. donates electrons by hyperconjugation

c. donates electrons by resonance

d. withdraws electrons inductively

Explanation:

a. The bromide ion is a highly electronegative ion (in the halide series). Electronegative substituents on acids increase the acidity by inductive electron withdrawal method. The higher the electronegativity of a substance, the greater the acidity. The halogens have this order of electronegativity:

F > Cl > Br>I

b. The carboxyl groups have a stabilization of the sigma and pi bonds. This is achieved through a special delocalization of electrons. Because of the delocalization, hyperconjugation is the result effect.

c. The NHCH₃ group has a highly electonegative nitrogen atom that pulls the electron cloud towards itself. In this case, it withdraws electrons inductively. As a result, it donates electrons by resonance.

d. The OCH₃ group has a highly electonegative oxygen atom. This oxygen atom withdraws electron cloud towards itself. As a result, it withdraws electrons inductively.

3 0

2 years ago

A 0.25 m solution of the sugar sucrose (c12h22o11) in water is tested for conductivity using the type of apparatus shown. Bulb w

Anvisha [2.4K]

Sucrose is a non ionic compound. It does liberates ion when dissolved in water unlike NaCl or other salts which dissolve in water and produce respective cations and anions.

Thus if any amount of sucrose is dissolved in water, it will form non ionic aqueous solution (it will dissolve completely). Thus sucrose solution being non electrolytic will not conduct electricity in aqueous solution.

the bulb will not light up as sucrose will remain in molecular form only

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2 years ago

The reaction SO2(g)+2H2S(g)←→3S(s)+2H2O(g) is the basis of a suggested method for removal of SO2 from power-plant stack gases. T

kifflom [539]

Answer : The equilibrium $SO_2$ pressure is, $3.93\times 10^{-5}torr$

Explanation :

The given balanced chemical reaction is,

$SO_2(g)+2H_2S(g)\rightleftharpoons 3S(s)+2H_2O(g)$

First we have to calculate the standard free energy of reaction $(\Delta G^o)$ .

$\Delta G^o=G_f_{product}-G_f_{reactant}$

$\Delta G^o=[n_{S(s)}\times \Delta G_f^0_{(S(s))}+n_{H_2O(g)}\times \Delta G_f^0_{(H_2O(g))}]-[n_{SO_2(g)}\times \Delta G_f^0_{(SO_2(g))}+n_{H_2S(g)}\times \Delta G_f^0_{(H_2S(g))}]$

where,

$\Delta G^o$ = standard free energy of reaction = ?

n = number of moles

Now put all the given values in this expression, we get:

$\Delta G^o=[3mole\times (0kJ/mol)+2mole\times (-228.57kJ/mol)]-[1mole\times (-300.4kJ/mol)+2mole\times (-33.01kJ/mol)]$

$\Delta G^o=-90.72kJ/mol$

Now we have to calculate the value of $K_p$

$\Delta G^o=-RT\ln K_p$

where,

$\Delta G_^o$ = standard Gibbs free energy = -90.72 kJ/mol

R = gas constant = 8.314 J/mole.K

T = temperature = 298 K

$K_p$ = equilibrium constant = ?

Now put all the given values in this expression, we get:

$-90.72kJ/mol=-(8.314J/mol.K)\times (298K) \ln K_p$

$K_p=7.98\times 10^{15}$

Now we have to calculate the value of $K_p$ .

The given balanced chemical reaction is,

$SO_2(g)+2H_2S(g)\rightleftharpoons 3S(s)+2H_2O(g)$

The expression for equilibrium constant will be :

$K_p=\frac{(p_{H_2O})^2}{(p_{H_2S})^2\times (p_{SO_2})}$

In this expression, only gaseous or aqueous states are includes and pure liquid or solid states are omitted.

Let the equilibrium $SO_2$ pressure be, x

Pressure of $SO_2$ = Pressure of $H_2S$ = x

Now put all the given values in this expression, we get

$7.98\times 10^{15}=\frac{(22)^2}{(x)^2\times (x)}$

$x=3.93\times 10^{-5}torr$

Thus, the equilibrium $SO_2$ pressure is, $3.93\times 10^{-5}torr$

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2 years ago

Which of the following statements is true about the following reaction?

MAVERICK [17]

The correct reaction equation is:

$3NaHCO_{3} (aq) + C_{6}H_{8}O_{7} (aq) \rightarrow 3CO_{2} (g) + 3H_{2}O (l) + Na_{3}C_{6}H_{5}O_{7} (aq)$

Answer:

b) 1 mole of water is produced for every mole of carbon dioxide produced.

Explanation: CONVERT EVERYTHING TO MOLES OR VOLUME, THEN COMPARE IT WITH THE COMPOUND'S STOICHIOMETRY IN CHEMICAL EQUATION.

a) 22.4 L of $CO_{2}$ gas is produced only when $\frac{22.4}{3}$ L of $C_{6}H_{8}O_{7}$ is reacted with 22.4 L of $NaHCO_{3}$ . So it is wrong.

b) Since in the chemical equation the stoichiometric coefficient of $CO_{2}$ and $H_{2}O$ are same so the number of moles or volume of each of them will be same whatever the amount of reactants taken. Therefore it is correct option.

c) $6.02\times 10^{23}$ molecules is equal 1 mole of $Na_{3}C_{6}H_{5}O_{7}$ if produced then 3 moles of $NaHCO_{3}$ is required, which is not given in the option. So it is wrong.

d) 54 g of water or 3 moles of $H_{2}O$ (Molecular Weight of water is 18 g) is produced when 3 moles of $NaHCO_{3}$ is used but in this option only one mole of $NaHCO_{3}$ is given. So it is wrong.

8 0

2 years ago

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