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4 years ago

If 42.9 mL of rubbing alcohol is

Chemistry

1 answer:

lisov135 [29]4 years ago

3 0

Answer:

19.8 %

Explanation:

V% = ( V of solute \ 100 ml of solution ) ×100% =

the volume of the solute in 100ml solition = 20 ml

42.9 ml of solute ----------215 ml solution

× ----------- 100 ml solution

42.6 × 100 ml ÷ 215 ml

= 19.8 ml of solute

the V% = (19.8 ÷ 100) ×100% = 19.8%

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Commercial grade fuming nitric acid contains about 90.0% HNO3 by mass with a density of 1.50 g/mL, calculate the molarity of the

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Answer:

Since molarity is defined as moles of solute per liter of solution, we need to find the number of moles of nitric acid, and the volume of solution.

molar mass of nitric acid (HNO3) = 1 + 14 + (3x16) = 15 + 48 = 63 g/mole

1.50 g/ml x 1000 ml = 1500 g/liter

1500 g/liter x 0.90 = 1350 g/liter of pure HNO3 (the 0.9 is to correct for the fact that it is 90% pure)

1350 g/liter x 1 mole/63 g = 21.43 moles/liter = 21 Molar HNO3

= 21 Molar of HNO3

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3 years ago

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Determine the equilibrium constant, Keq, at 25°C for the reaction

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Explanation:

The given chemical reaction is:

$2Br^- (aq) + I_2(s) Br_2(l) + 2I^- (aq)$

$E^ocell=oxidation potential of anode + reduction potential of cathode\\$

The relation between Eo cell and Keq is shown below:

$deltaG=-RTlnK_e_q\\delta=-nFE^o cell\\=>nFE^o cell=RTlnK_e_q\\lnK_e_q=\frac{nF}{RT} E^o cell$

The value of Eo cell is:

Br- undergoes oxidation and I2 undergoes reduction.

Reduction takes place at cathode.

Oxidation takes place at anode.

Hence,

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F=96485 C/mol

n=2 mol

R=8.314 J.K-1.mol-1

T=298K

Substitute all these values in the above formula:

$ln K_e_q=\frac{2mol* 96485 C/mol}{8.314 J.K^-^1.mol^-^1x298K} \\\\lnK_e_q=77.8\\K_e_q=e^7^7^.^8\\=>K_e_q=6.13x10^3^3$

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Keq=6.13x10^33

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3 years ago

17 Which substance can not be broken down by a chemical change?(1) ammonia (3) propanal

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4 years ago

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How is kinetic energy related to the Kelvin scale?

IRINA_888 [86]

The Kelvin temperature of a substance is directly equal to the avg kinetic energy of particles of a substance. Hope that is what your looking for

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3 years ago

The bonds in the reactants of Figure 7-3 contained 372 kJ of chemical energy and the bonds in the products contained 350 kJ of c

satela [25.4K]

Answer: 22 kJ amount of energy is released in the following reaction.

Explanation: There are two types of reaction on the basis of amount of heat absorbed or released.

1. Endothermic reactions: These are the type of reactions in which reactants absorb heat to form the products. The energy of the reactants is less than the energy of the products.

2. Exothermic reactions: These are the type of reactions in which heat is released from the chemical reactions. The energy of the products is less than the reactants.

Sign convention for $\Delta H$ : This value is negative for exothermic reactions and positive for endothermic reactions.

For the given chemical reaction,

Energy of the products is less than the energy of the reactants, Hence, this reaction will be a type of exothermic reaction and energy will be released during this chemical change.

Amount of energy released = (350 - 372) kJ = -22kJ

Negative sign symbolizes the energy is being released. So, 22 kJ amount of energy is released in the following reaction.

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3 years ago