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2 years ago

11

Im about to take first year chemistry for engineering. Should i review or will this be done in class? If yes what are some conce

pts i should review. It would help if you could provide a list of key concepts/definitions/properties.
P.S.: I remember little to nothing.

1 answer:

sashaice [31]2 years ago

6 0

You should always study. you can be above your class. thats what i do.. search google for ur course. they can tell u some key points for it. u should even study what you know and want to know as well.

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Need help fast please

fenix001 [56]

Explanation:

When the reaction takes place,2 grams of carbon dioxide will be made but vaporized into air.

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2 years ago

what pressure is generated when 5 mol of ethane is stored in a volume of 8 dm 3 at 25°C? Base calculations on each of the follow

Goshia [24]

Answer:

a) 40,75 atm

b) 30,11 atm

Explanation:

The Ideal Gas Equation is an equation that describes the behavior of the ideal gases:

PV = nRT

where:

P = pressure [atm]
V = volume [L]
n = number of mole of gas [n]
R= gas constant = 0,08205 [atm.L/mol.°K]
T=absolute temperature [°K]

<em>Note: We can express this values with other units, but we must ensure that the units used are the same as those used in the gas constant.</em>

The truncated virial equation of state, is an equation used to model the behavior of real gases. In this, unlike the ideal gas equation, other parameters of the gases are considered as the <u>intermolecular forces</u> and the <u>space occupied</u> by the gas

$\frac{Pv}{RT} = 1 + \frac{B}{v}$

where:

v is the molar volume [L/mol]
B is the second virial coefficient [L/mol]
P the pressure [atm]
R the gas constant = 0,08205 [atm.L/mol.°K]

a) Ideal gas equation:

We convert our data to the adecuate units:

n = 5 moles

V = 3 dm3 = 3 L

T = 25°C = 298°K

We clear pressure of the idea gas equation and replace the data:

PV = nRT ..... P = nRT/V = 5 * 0,08205 * 298/3 =40,75 atm

b) Truncated virial equation:

We convert our data to the adecuate units:

n = 5 moles

V = 3 dm3 = 3 L

T = 25°C = 298°K

B = -156,7*10^-6 m3/mol = -156,7*10^-3 L/mol

We clear pressure of the idea gas equation and replace the data:

$\frac{Pv}{RT} = 1 + \frac{B}{v} ...... P = (1 + \frac{B}{v}) \frac{RT}{v}$

and v = 3 L/5 moles = 0,6 L/mol

$P = (1 + \frac{-156,7*10^{-3} }{0,6} ) \frac{0,08205*298}{0,6} = 30,11 atm$

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3 years ago

Sodium oxide contains Na+ ions and O2- ions.<br> Give the formula of sodium oxide

mixer [17]

To be honest, I learned this in school so I'll tell you XD

The formula of sodium oxide is Na2O

8 0

2 years ago

Measurements include

Keith_Richards [23]

There’s lots of measurements. (m, kg, s, mol, cm, in, mm) etc

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3 years ago

What would be the composition and ph of an ideal buffer prepared from lactic acid (ch3chohco2h), where the hydrogen atom highlig

Mashutka [201]

Answer:

$P_H =2.86$

$c=1.4\times 10^{-4}$

Explanation:

first write the equilibrium equaion ,

$C_3H_6O_3$ ⇄ $C_3H_5O_3^{-} +H^{+}$

assuming degree of dissociation $\alpha$ =1/10;

and initial concentraion of $C_3H_6O_3$ =c;

At equlibrium ;

concentration of $C_3H_6O_3 = c-c\alpha$

$[C_3H_5O_3^{-} ]= c\alpha$

$[H^{+}] = c\alpha$

$K_a = \frac{c\alpha \times c\alpha}{c-c\alpha}$

$\alpha$ is very small so $1-\alpha$ can be neglected

and equation is;

$K_a = {c\alpha \times \alpha}$

$[H^{+}] = c\alpha$ = $\frac{K_a}{\alpha}$

$P_H =- log[H^{+} ]$

$P_H =-logK_a + log\alpha$

$K_a =1.38\times10^{-4}$

$\alpha = \frac{1}{10}$

$P_H= 3.86-1$

$P_H =2.86$

composiion ;

$c=\frac{1}{\alpha} \times [H^{+}]$

$[H^{+}] =antilog(-P_H)$

$[H^{+} ] =0.0014$

$c=0.0014\times \frac{1}{10}$

$c=1.4\times 10^{-4}$

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3 years ago