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2 years ago

You are asked to make 500 mL of a 0. 250 M sodium chloride (NaCl) solution.

Chemistry

1 answer:

nignag [31]2 years ago

3 0

Answer:

a. .125 mol b. 7.25g

Explanation:

a. To get the moles multiply the volume by the molarity.

.5L*.25M=.125mol NaCl

b. The molar mass is provided so multiply the moles by the molar mass to get the amount of grams of nacl.

.125mol*58molar mass=7.25g nacl to make the solution

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This reaction is sometimes used to inflate life rafts, weather balloons, and the like, where a simple, compact means of generati

tia_tia [17]

Answer: 10.2 grams

Explanation:

The balanced chemical reaction is :

$CaH_2(s)+2H_2O(l)\rightarrow Ca(OH)_2(aq)+2H_2(g)$

According to the ideal gas equation:

$PV=nRT$

P = Pressure of the gas = 740 torr = 0.97 atm (760torr=1atm)

V= Volume of the gas = 12.0 L

T= Temperature of the gas = 19°C = 292 K $0^0C=273K$

R= Gas constant = 0.0821 atmL/K mol

n= moles of gas

$n=\frac{PV}{RT}=\frac{0.97\times 12.0}{0.0821\times 292}$

$n=0.48$

According to stoichiometry:

2 moles of hydrogen are generated by = 1 mole of $CaH_2$

Thus 0.48 moles of hydrogen are generated by = $\frac{1}{2}\times 0.48=0.24$ moles of $CaH_2$

Mass of $CaH_2=moles\times {\text {Molar mass}}=0.24mol\times 42g/mol=10.2g$

Thus 10.2 grams of $CaH_2$ are needed to generate 12.0 L of hydrogen gas if the pressure of hydrogen is 740. torr at 19°C

5 0

3 years ago

Consider 5.00 L of a gas at 365 mmHg and 20. ∘C . If the container is compressed to 2.50 L and the temperature is increased to 3

pickupchik [31]

First convert celcius to Kelvin.

20 + 273 = 293K

31 + 273 = 304K

Now we can set up an equation based on the information we have.

V1 = 5

P1 = 365

T1 = 293

V2 = 5

P1 = x

T2 = 304

The equation be: $\frac{(5)(365)}{293} = \frac{5x}{304}$

Now just solve.

1825/293 = 5x/304

Cross multiply.

554800 = 1465x

Divide both sides by 1465

x = 378.7030717 which can then be rounded to 378.7 mmHg

4 0

3 years ago

A chemical reaction was carried out three times. The mass of the product was 8.93 g for the first trial, 8.94 g for the second t

joja [24]

The three mass value measure are precise mass

<u>explanation</u>

precise mass is term use to describe data from experiment that have been repeated several times. An experiment that yield tightly grouped set of data it has a high precision. 8.93 , 8.94 and 8.92 are precise mass since they have repeated severally

6 0

4 years ago

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Bumek [7]

Answer:

Converted to renewable ones

exhausted or depleted

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3 years ago

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Anton [14]

Answer:

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Explanation:

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3 years ago