What is always conserved in a chemical reaction? (3 points)

Which observations is the best evidence that unknown liquid X is a composed of only pure substance

Angelina_Jolie [31]

Answer:

A substance that is composed only of atoms having the same atomic number is ... 36 grams of an unknown liquid at its boiling point,.

4 0

2 years ago

Iron is obtained commercially by the reaction of hematite (Fe2O3) with carbon monoxide. How many grams of iron are produced if 1

kherson [118]

CO is the limiting reactant
( 25.0 x 3 = 75 moles of CO are required)

Moles Fe = 30.0 x 2 / 3 = 20.0
mass Fe = 20.0 x 55.847 g/mol=1117 g 

I'm just saying

5 0

3 years ago

What 2 properties make capillary action possible

Natali5045456 [20]

Cohesion and adhesion

7 0

2 years ago

What state of matter has a definite shape and volume.

anastassius [24]

Solids have a definite shape and volume. They are always the same shape no matter what they are contained in; their volume is also the same because they don't change unless you add or take away from it.

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Liquids have an indefinite shape but definite volume. They expand to fill out the space they are contained in, but their volume doesn't change unless you take out or add more of the liquid.

Gases have an indefinite shape and volume. Gases expand to fill out the space they are in and also don't have a clear shape because they are not always in one form.

3 0

2 years ago

Based on the sign of E cell, classify these reactions as spontaneous or non spontaneous as written.? assume standard conditions.

sammy [17]

A electrochemical reaction is said to be spontaneous, if $E^{0} cell is positive.$

Answer 1:
Consider reaction: Ni^2+ (aq) + S^2- (aq) ----> + Ni (s) + S (s)

The cell representation of above reaction is given by;
 $S^{2-}/S // Ni^{2+}/Ni$

Hence, $E^{0}cell = E^{0} Ni^{2+/Ni} - E^{0} S/S^{2-}$
we know that, ${E^{0} Ni^{2+}/Ni = -0.25 v$
and ${E^{0} S/ S^{2-} = -0.47 v$

Therefore, $E^{0} cell$ = - 0.25 - (-0.47) = 0.22 v

Since, $E^{0} cell$ is positive, hence cell reaction is spontaneous
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Answer 2:
Consider reaction: Pb^2+ (aq) +H2 (g) ----> Pb (s) +2H^+ (aq)

The cell representation of above reaction is given by;
 $H_{2} / H^{+} // Pb^{2+} /Pb$

Hence, $E^{0}cell = E^{0} Pb/Pb^{2+} - E^{0} H_{2}/H^{+}$
we know that, ${E^{0} Pb^{2+}/Pb = -0.126 v$
and ${E^{0} H_{2}/ H^{+} = -0 v$

Therefore, $E^{0} cell$ = - 0.126 - 0 = -0.126 v

Since, $E^{0} cell$ is negative, hence cell reaction is non-spontaneous.

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Answer 3:
Consider reaction: 2Ag^+ (aq) + Cr(s) ---> 2 Ag (s) +Cr^2+ (aq)

The cell representation of above reaction is given by;
 $Cr/Cr^{2+} // Ag^{+}/Ag$

Hence, $E^{0}cell = E^{0} Ag^{+}/Ag - E^{0} Cr/Cr^{2+}$
we know that, ${E^{0} Ag^{+}/Ag = -0.22 v$
and ${E^{0} Cr/ Cr^{2+} = -0.913 v$

Therefore, $E^{0} cell$ = - 0.22 - (-0.913) = 0.693 v

Since, $E^{0} cell$ is positive, hence cell reaction is spontaneous

8 0

3 years ago

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