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3 years ago

30PTS EASY QUESTION

Chemistry

2 answers:

dlinn [17]3 years ago

6 0

Answer:

Thermal, electrical, chemical, nuclear, and electromagnetic energy

Explanation:

irga5000 [103]3 years ago

4 0

Thermal, electrical, chemical, nuclear, and electromagnetic energy. (just gave you more than two just incase)

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A glucose solution that is prepared for a patient should have a concentration of 180 g/L. A nurse has 18 g of glucose. How

Irina-Kira [14]

<h3>Answer:</h3>

0.10 L

<h3>Explanation:</h3>

The concentration of glucose is given as 180 g/L

The mass of glucose is 18 g

Concentration in g/L is calculated by dividing mass of the solute by the volume of the solution.
When calculating molarity on the other hand, we divide number of moles of the solute by the volume of the solution.

Concentration in g/L = Mass of solute ÷ Volume

Rearranging the formula,

Volume = Mass of the solute ÷ concentration

= 18 g ÷ 180 g/L

= 0.10 L

Therefore, volume of water is 0.10 L

6 0

3 years ago

List a mixture that can be separated by fractional distillation

vivado [14]

Separation of components of crude oil

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3 years ago

Water is formed when two hydrogen atoms bond to an oxygen atom. The hydrogen and the oxygen in this example are different A) com

Nata [24]

Hydrogen and oxygen are elements.

8 0

3 years ago

A voltaic cell consists of a Zn>Zn2+ half-cell and a Ni>Ni2+ half-cell at 25 °C. The initial concentrations of Ni2+ and Zn

nlexa [21]

Answer :

(a) The initial cell potential is, 0.53 V

(b) The cell potential when the concentration of $Ni^{2+}$ has fallen to 0.500 M is, 0.52 V

(c) The concentrations of $Ni^{2+}$ and $Zn^{2+}$ when the cell potential falls to 0.45 V are, 0.01 M and 1.59 M

Explanation :

The values of standard reduction electrode potential of the cell are:

$E^0_{[Ni^{2+}/Ni]}=-0.23V$

$E^0_{[Zn^{2+}/Zn]}=-0.76V$

From this we conclude that, the zinc (Zn) undergoes oxidation by loss of electrons and thus act as anode. Nickel (Ni) undergoes reduction by gain of electrons and thus act as cathode.

The half reaction will be:

Reaction at anode (oxidation) : $Zn\rightarrow Zn^{2+}+2e^-$ $E^0_{[Zn^{2+}/Zn]}=-0.76V$

Reaction at cathode (reduction) : $Ni^{2+}+2e^-\rightarrow Ni$ $E^0_{[Ni^{2+}/Ni]}=-0.23V$

The balanced cell reaction will be,

$Zn(s)+Ni^{2+}(aq)\rightarrow Zn^{2+}(aq)+Ni(s)$

First we have to calculate the standard electrode potential of the cell.

$E^o=E^o_{cathode}-E^o_{anode}$

$E^o=E^o_{[Ni^{2+}/Ni]}-E^o_{[Zn^{2+}/Zn]}$

$E^o=(-0.23V)-(-0.76V)=0.53V$

(a) Now we have to calculate the cell potential.

Using Nernest equation :

$E_{cell}=E^o_{cell}-\frac{0.0592}{n}\log \frac{[Zn^{2+}]}{[Ni^{2+}]}$

where,

n = number of electrons in oxidation-reduction reaction = 2

$E_{cell}$ = emf of the cell = ?

Now put all the given values in the above equation, we get:

$E_{cell}=0.53-\frac{0.0592}{2}\log \frac{(0.100)}{(1.50)}$

$E_{cell}=0.49V$

(b) Now we have to calculate the cell potential when the concentration of $Ni^{2+}$ has fallen to 0.500 M.

New concentration of $Ni^{2+}$ = 1.50 - x = 0.500

x = 1 M

New concentration of $Zn^{2+}$ = 0.100 + x = 0.100 + 1 = 1.1 M

Using Nernest equation :

$E_{cell}=E^o_{cell}-\frac{0.0592}{n}\log \frac{[Zn^{2+}]}{[Ni^{2+}]}$

Now put all the given values in the above equation, we get:

$E_{cell}=0.53-\frac{0.0592}{2}\log \frac{(1.1)}{(0.500)}$

$E_{cell}=0.52V$

(c) Now we have to calculate the concentrations of $Ni^{2+}$ and $Zn^{2+}$ when the cell potential falls to 0.45 V.

Using Nernest equation :

$E_{cell}=E^o_{cell}-\frac{0.0592}{n}\log \frac{[Zn^{2+}+x]}{[Ni^{2+}-x]}$

Now put all the given values in the above equation, we get:

$0.45=0.53-\frac{0.0592}{2}\log \frac{(0.100+x)}{(1.50-x)}$

$x=1.49M$

The concentration of $Ni^{2+}$ = 1.50 - x = 1.50 - 1.49 = 0.01 M

The concentration of $Zn^{2+}$ = 0.100 + x = 0.100 + 1.49 = 1.59 M

5 0

3 years ago

Ionic salts are used for melting ice on roads for two reasons: they are effective at lowering the freezing point when they disso

Anuta_ua [19.1K]

Answer:

CaCl2=1

KCl=3

Explanation:

CaCl2 has a very high heat of solution hence it is best at melting ice. It is better than all the other salts mentioned. Its dissolution in water produces a lot of heat which melts the ice.

3 0

3 years ago