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Fofino [41]
3 years ago
5

Which pair of properties describes the elements in Group 18?

Chemistry
1 answer:
olga55 [171]3 years ago
6 0

Answer

-12

Explanation:

Cs 22 is not close to -12

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GIVING BRAINLIEST One mole of hydrogen gas (H2), reacts with one mole of bromine Br2(g) to produce 2 moles of hydrogen bromide g
JulsSmile [24]

Answer:

The equation to show the the correct form to show the standard molar enthalpy of formation:

\frac{1}{2}H_2(g) +\frac{1}{2}Br_2(l)\rightarrow HBr(g) ,\Delta H_{f}^o= -36.29 kJ

Explanation:

The standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy during the formation of 1 mole of the substance from its constituent elements, with all substances in their standard states.

Given, that 1 mole of H_2 gas and 1 mole of Br_2 liquid gives 2 moles of HBr gas as a product.The reaction releases 72.58 kJ of heat.

H_2(g) + Br_2(l)\rightarrow 2HBr(g) ,\Delta H_{f}^o= -72.58kJ

Divide the equation by 2.

\frac{1}{2}H_2(g) +\frac{1}{2}Br_2(l)\rightarrow HBr(g) ,\Delta H_{f}^o= -36.29 kJ

The equation to show the the correct form to show the standard molar enthalpy of formation:

\frac{1}{2}H_2(g) +\frac{1}{2}Br_2(l)\rightarrow HBr(g) ,\Delta H_{f}^o= -36.29 kJ

4 0
3 years ago
If the solubility of sugar at 25ºC is 211 g/100 g H2O, what mass of sugar can be dissolved in 300 g of H2O?
ladessa [460]

Answer:

633 grams of sugar can be dissolved in 300 g of H₂O

Explanation:

Solubility is the measure of the ability of a certain substance to dissolve in another and form a homogeneous system.  Solubility is then the maximum amount of a solute that a solvent can receive and is expressed by concentration units.

The rule of three or is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them. That is, what is intended with it is to find the fourth term of a proportion knowing the other three. Remember that proportionality is a constant relationship or ratio between different magnitudes.

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied. To solve a direct rule of three, the following formula must be followed:

a ⇒ b

c ⇒ x

Then:

x=\frac{c*b}{a}

You can apply the rule of three as follows: if by definition of solubility in 100 grams of H₂O there are 211 grams of sugar, in 300 g of H₂O how much sugar is there?

sugar=\frac{300 grams of H_{2}O *211 grams of sugar}{100 grams of H_{2}O}

sugar= 633 grams

<u><em>633 grams of sugar can be dissolved in 300 g of H₂O</em></u>

7 0
2 years ago
Read 2 more answers
Assuming that all the energy given off in the reaction goes to heating up only the air in the house, determine the mass of metha
nirvana33 [79]

Answer:

0.92 kg

Explanation:

The volume occupied by the air is:

35.0m\times 35.0m \times 3.2m \times \frac{10^{3}L }{1m^{3} } =3.9 \times 10^{6} L

The moles of air are:

3.9 \times 10^{6} L \times \frac{1.00mol}{22.4L} =1.7 \times 10^{5}mol

The heat required to heat the air by 10.0 °C (or 10.0 K) is:

1.7 \times 10^{5}mol \times \frac{30J}{K.mol} \times 10.0 K = 5.1 \times 10^{7}J

Methane's heat of combustion is 55.5 MJ/kg. The mass of methane required to heat the air is:

5.1 \times 10^{7}J \times \frac{1kgCH_{4}}{55.5 \times 10^{6} J } =0.92kgCH_{4}

3 0
2 years ago
Mole Conversion: How many molecules are there in 6.70 moles of methane, CH4 ​
raketka [301]

Answer:

Explanation:

1 mol of methane = 6.02 * 10^23 molecules

6.70 mol of methane = x

Cross multiply

x = 6.70 * 6.02 * 10^23

x = 4.033 * 10^23 molecules.

8 0
3 years ago
Read 2 more answers
Is centigrams or grams bigger.<br> example: which unit is larger.<br> 35cg or 35 g
sp2606 [1]

Answer:

35g

Explanation:

5 0
2 years ago
Read 2 more answers
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