Chemistry, 11.02.2021 22:30 maryforney

Why is bromine written as Bra in the following reaction?
Na + Br2 →

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Answer from: Quest

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.

Answer from: Quest

Hairy thick gross thing? idk

Answer from: Quest

option c: 1605.1 kj

the balanced chemical reaction for combustion of methane is as follows:

$ch_{4}+2o_{2}\rightarrow co_{2}+2h_{2}o$

here, enthalpy formation of $ch_{4}, o_{2}, co_{2} and h_{2}o$ is -74.7 kj/mol, 0 kj/mol, -393.5 kj/mol and -241.82 kj/mol respectively.

the heat released or $\delta h_{reaction}$ can be calculated as follow:

$\delta h_{reaction}=\delta h_{f}_{co_{2}}+2(\delta h_{f}_{h_{2}o} h_{f}_{ch_{4}}-2\delta h_{f}_{o_{2}})$

putting the values,

$\delta h_{reaction}=-393.5 kj/mol+(.82 kj/.6-(2)(0 kj/mol))=802.54 kj/mol$

thus, heat released by combustion of 1 mol of methane is 802.54 kj/mol. thus, for 2 mol, heat released will be:

$\delta h_{reaction}=(2 mol)(802.54 kj/mol)=1605.1 kj$

therefore, heat released by the combustion of 2 mol of methane is 1605.1 kj.

Answer from: Quest

Starsstars are giant balls of hot gases that can produce their own light. stars give out energy by converting hydrogen gas into helium in their cores. stars are gigantic in size and have immense gravitational attraction. the sun is a medium sized star that gives us energy and makes life on earth possible.planetsplanets are large (almost) spherical objects that revolve around the sun. planets move in fixed orbits around the sun. there are 8 planets in our solar system. planets may be made of rocks, metals, gases like hydrogen, nitrogen and methane. the earth is also a planet and is the only place in the universe that we know that supports life. planets that revolve around other stars are called exoplanets.satellitessatellites are objects that revolve around planets. they form the essential part of the celestial bodies. these may be of natural origin or sent by humans. the moon is a natural satellite of the earth and revolves around it because it is bound by the earth’s gravitational pull. man also has placed artificial or man-made satellites around the earth and other planets to study them and for communication purposes.i think this is correct not 100%