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3 years ago

How can you identify an element that is a metalloid?

1 answer:

7 0

On the periodic table, the elements colored yellow, which generally border the stair -step line , are considered to be metalloids

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The solubility of CO2 in water is 0.161 g/100 mL at 20oC and a partial pressure of CO2 of 760 mmHg. What partial pressure of CO2

Schach [20]

Answer: The partial pressure of carbon dioxide having solubility 0.886g/100mL is 4182.4 mmHg

Explanation:

Henry's law states that the amount of gas dissolved or molar solubility of gas is directly proportional to the partial pressure of the liquid.

The equation given by Henry's law is:

$C_{CO_2}=K_H\times p_{CO_2}$ ......(1)

where,

$C_{CO_2$ = solubility of carbon dioxide in water = 0.161 g/100 mL

$K_H$ = Henry's constant = ?

$p_{CO_2}$ = partial pressure of carbon dioxide = 760 mmHg

Putting values in equation 1, we get:

$760mmHg=K_H\times 0.161g/100mL\\\\K_H=\frac{760mmHg}{0.161g/100mL}=4720.5g.mmHg/100mL$

Now, calculating the pressure of carbon dioxide using equation 1, we get:

$C_{CO_2$ = solubility of carbon dioxide in water = 0.886 g/100 mL

$K_H$ = Henry's constant = 4720.5 g.mmHg/100 mL

$p_{CO_2}$ = partial pressure of carbon dioxide = ?

Putting values in equation 1, we get:

$p_{CO_2}=4720.5g.mmHg/100mL\times 0.886g/100mL=4182.4mmHg$

Hence, the partial pressure of carbon dioxide having solubility 0.886g/100mL is 4182.4 mmHg

4 0

3 years ago

Is helium a homogeneous or heterogeneous mixture or compound or element?

sattari [20]

Helium is a chemical ELEMENT of the family of noble gases. Its chemical symbol is 'He' which has an atomic number of 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table. Although it doesn't really react under normal conditions, it is the second most abundant element in the universe.

Elements are pure substances that cannot be broken down any further.

8 0

3 years ago

How does the magnetic field surrounding earth benefit humankind

Xelga [282]

C, it prevents the Earth from ultraviolet radiation and other harmful substances from space

5 0

4 years ago

Read 2 more answers

What is the mole to mole ratio of LiOH to HBr for the following reaction?

umka21 [38]

Explanation:

so moles = mass ÷ mr (1+ 79.9)

so 10.00g ÷ 80.9

which is 0.1236093943

so to 3 S.F is 0.124 moles

also there is 1 to 1 ratio for LiOH to HBr

hope this helps :)

8 0

3 years ago

A 100.00 ml of volume of 0.500 M HCl was mixed with 100.00 ml of 0.500 M KOH in a constant pressure calorimeter. The initial tem

Virty [35]

Answer:

The heat of the reaction = -1985 J = -1.985 kJ

The enthalpy of the reaction is -39.7 kJ/ mol

Explanation:

Step 1: Data given

Volume of HCl = 100 mL the heat of the reaction = 0.1 L

Molarity of HCl solution = 0.500 M

Volume of KOH = 100 mL = 0.1 L

Molarity of KOH solution = 0.500 M

Initial temperature = 23.0 °C

Final temperature = 25.5 °C

Specific heat of the solution = 3.97 J/°C *g

Density of the solution = 1g/ mL

Step 2: Calculate heat

Q = m*c*ΔT

with m = the mass of both solution : 100g + 100 g ( since density = 1g/mL) = 200 g

c = the specific heat = 3.97 J/°C*g

ΔT = T2 -T1 = 25.5 = 23 = 2.5 °C

Q = 200g *3.97 J/°C*g * 2.5°C = 1985 J (= -1985 J because it's exothermic)

Step 3: Calculate the number of moles

Number of moles = Molarity * Volume

Number of moles = 0.5 * 0.1 L = 0.05 moles

(Moles of the acid are equal to the moles of water produced.

Moles of solution = 0.05 moles)

Step 4: Calculate the enthalpy of the reaction

ΔH = heat change /Number of moles

= -1.985 kJ/ 0.05 moles

=- 39700 J/mol = -39.7 kJ/ mol

The enthalpy of the reaction is -39.7 kJ/ mol

The enthalpy of the reaction is negative, this means the reaction is exothermic ( which means the final temperature is higher than the initial temperature.)

7 0

4 years ago