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3 years ago

How many grams of mgo are produced during an enthalpy change of -231 kj ?

Chemistry

1 answer:

SCORPION-xisa [38]3 years ago

3 0

The reaction for the formation of MgO(s):

2 Mg (s) + O2(g) -à 2MgO(s) ΔH = -601.24 kJ/mol

The enthalpy information is taken from: http://webbook.nist.gov/cgi/inchi?ID=C1309484&Mask=2

From the equation and with an enthalpy change of -231 kJ:

-231 kJ * 2 mol Mg * (1/-601.24 kJ/mol) = 0.76841 mol Mg

Then, with the molar mass of MgO = 40.3,

0.76841 mol Mg *(2 mol MgO/2 mol Mg)* 40.3 g/mol MgO = 30.967 g MgO

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Suppose you have been given the task of distilling a mixture of hexane + toluene. Pure hexane has a refractive index of 1.375 an

rosijanka [135]

Answer:

Mole fraction of hexane in your sample is 0,746

Explanation:

Based on the information you can write the following equations:

X + Y = 1 (1)

Where X is mole fraction of hecane and Y is mole fraction of toluene

Also, based on the assumption that the refractive index of the hexane + toluene mixture varies linearly with mole fraction you can write:

1,375X + 1497Y = 1406 (2)

Replacing (1) in (2):

1,375X + 1,497(1-X) = 1,406

1,375X - 1,497X + 1,497 = 1,406

-0,122X = -0,091

X = -0,091/-0,122

X = 0,746

Thus, the mole fraction of hexane in your sample is 0,746

Also you can know the mole fraction of toluene replacing this value in (1):

0,746 - Y = 1

Y = 1-0,746

Y = 0,254

I hope it helps!

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3 years ago

the buret is dirty and drops of NaOH cling to the side walls of the buret as it drained. How does this affect the result for NaO

kykrilka [37]

Since this has to do with titration, the measured volume of NaOH used would be less than the actual volume used because some of the unused NaOH would cling to the sides of the buret and therefore wouldn't factor into the measurement

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4 years ago

Four states or phases of matter

Pie

Answer:

Solid, Liquid, Gas and, Plasma

Explanation:

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Why does salt dissolve in water?

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3 years ago

1 Clouds are formed when millions of drops of water become suspended in the air. Which

ioda

Answer:

C Condensation of water vapor

Explanation:

One of the components of the atmosphere is water vapour. Water vapour is always present in air.

This water vapour may combine with particles of dust and smoke and condense around them to form clouds.

As more water vapour condenses and coalesces, the clouds become thicker and precipitation eventually follows.

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