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densk [106]
3 years ago
8

Calculate the approximate enthalpy change, ΔHrxn, for the combustion of methane:

Chemistry
2 answers:
VashaNatasha [74]3 years ago
6 0
<span>We subtract the enthalpies of the products by the enthalpies of the reactants, taking into account their stoichiometric coefficients:
</span>2ΔH(H2O) + ΔH(CO2) - ΔH(CH4) - ΔH(2O2)= 2(928) + 1598 - 1656 - 2(498)= 802 kJ / 1 mol methane






Alekssandra [29.7K]3 years ago
5 0
<span>The heat of combustion is obtained by getting the difference between the summation of enthalpies of the products and the enthalpies of the reactants. Hence the equation is enthalpy change= 1598 kJ+2*928 kJ-1656 kJ-498 kJ. The answer is 1300 kJ.</span>
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Answer:

240 seconds

Explanation:

Data Given:

Distance Radio travel to earth = 7.19 ×10⁷ km

Speed of this radio signal = 3.00 ×10⁸ m/s

Solution:

First convert Km to m

1 km = 1000 m

7.19 ×10⁷ km = 7.19 ×10⁷ x 1000 = 7.19 × 10¹⁰m

Formula used to calculate time

            Speed (S) = distance (d) / time (t)

rearrange above equation for time

            time (t) = distance (d) / Speed (S) . . . . . . . . .(1)

Put values in equation 1

            time (t) = 7.19 × 10¹⁰/ 3.00 ×10⁸ m/s

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So 240 seconds it take for the signal to reach the earth

6 0
4 years ago
The pressure of a sample of helium in a 200. ml container is 2.0 atm. If the helium is compressed to a pressure of 40. atm witho
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Answer:

V_2=10mL

Explanation:

Hello there!

In this case, according to the given information, it will be possible for us to solve this problem by using the Boyle's law as an inversely proportional relationship between pressure and volume:

P_2V_2=P_1V_1

In such a way, we solve for the final volume, V2, and plug in the initial volume and pressure and final pressure to obtain:

V_2=\frac{P_1V_1}{P_2} \\\\V_2=\frac{2.0atm*200.mL}{40.atm}\\\\V_2=10mL

Regards!

5 0
3 years ago
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amm1812

Answer:

When melted or dissolved in water.

Explanation:

Potassium bromide in its solid form contains ions, which are charged atoms. Through the heating process, the melted potassium bromide becomes an ionic liquid. If solid potassium bromide is dissolved, for example in water, the resulting release of ions allows it to conduct electricity.

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