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3 years ago

PLEASE HELP FAST!! I need someone to see if my answers are correct!

Chemistry

1 answer:

11111nata11111 [884]3 years ago

5 0

Explanation:

1. The given statement is true.

Colligative properties are properties of the ideal solution which depends upon the amount or particles of solute dissolved in fixed amount of solvent. These properties do not depend upon the nature of the solute.

2. Ammonia when dissolves in water gives two particles:

$NH_3+H_2O\rightarrow NH_{4}^++OH^-$

3. Hexane is an non polar molecule. when dissolved in water its structural unit gives only 1 particle.

4. At higher altitudes atmospheric pressure decreases.Vapor pressure of a liquid and atmospheric pressure directly linked to each other which means that liquid will boil at lower temperature than it normal boiling temperature when boiled in higher altitudes.

So, water will boil at temperature lower than 100° C.

5. $Al(NO_3)_3$ is ionic compounds which dissociated into 4 particles when dissolved in water.

$Al(NO_3)_3+H_2O\rightarrow Al^{3+}+3NO_{3}^-$

6. $BaBr_2$ is ionic compounds which dissociated into 3 particles when dissolved in water.

$BaBr_2+H_2O\rightarrow Ba^{2+}+2Br^-$

7. The correct answer is option A.

$\Delta T_b=i\times K_b\times molality$

i = van't Hoff Factor

$\Delta T_b\propto i$

Larger value i more will be elevation in boiling point of the solvent.

1 molecule of Ammonium phosphate dissociate into 4 particles when dissolved in water.

$(NH_4)_3PO_4+H_2O\rightarrow 3NH_{4}^++PO_{4}^{3-}$

8.The correct answer is option B.

$\Delta T_f=i\times K_f\times molality$

i = van't Hoff Factor

$\Delta T_f\propto i$

Larger value i more will be depression in freezing point of the solvent.

1 molecule of potassium sulfate dissociates into 3 particles when dissolved in water.

$K_2SO_4+H_2O\rightarrow 2K^{+}+SO_{4}^{2-}$

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Using the following standard reduction potentials, Fe3+(aq) + e- → Fe2+(aq) E° = +0.77 V Ni2+(aq) + 2 e- → Ni(s) E° = -0.23 V ca

lina2011 [118]

<u>Answer:</u> The above reaction is non-spontaneous.

<u>Explanation:</u>

For the given chemical reaction:

$Ni^{2+}(aq.)+2Fe^{2+}(aq.)\rightarrow 2Fe^{3+}(aq.)+Ni(s)$

Here, nickel is getting reduced because it is gaining electrons and iron is getting oxidized because it is loosing electrons.

We know that:

$E^o_{(Fe^{3+}/Fe^{2+})}=0.77V\\E^o_{(Ni^{2+}/Ni)}=-0.23V$

Substance getting oxidized always act as anode and the one getting reduced always act as cathode.

To calculate the $E^o_{cell}$ of the reaction, we use the equation:

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

$E^o_{cell}=-0.23-0.77=-1.0V$

Relationship between standard Gibbs free energy and standard electrode potential follows:

$\Delta G^o=-nFE^o_{cell}$

As, the standard electrode potential of the cell is coming out to be negative for the above cell. Thus, the standard Gibbs free energy change of the reaction will become positive making the reaction non-spontaneous.

Hence, the above reaction is non-spontaneous.

3 0

3 years ago

I need help please ASAP

Yuliya22 [10]

Answer:

the name for NO is nitrogen monoxide

6 0

3 years ago

What is the composition, in atom percent, of an alloy that consists of a) 5.5 wt% Pb and b) 94.5 wt% of Sn? Assume that the atom

Anastaziya [24]

Answer : The percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.

Explanation :

First we have to calculate the number of atoms in 5.5 wt% Pb and 94.5 wt% of Sn.

As, 207.2 g of lead contains $6.022\times 10^{23}$ atoms

So, 5.5 g of lead contains $\frac{5.5}{207.2}\times 6.022\times 10^{23}=1.59\times 10^{22}$ atoms

and,

As, 118.71 g of lead contains $6.022\times 10^{23}$ atoms

So, 94.5 g of lead contains $\frac{94.5}{118.71}\times 6.022\times 10^{23}=4.79\times 10^{23}$ atoms

Now we have to calculate the percent composition of Pb and Sn in atom.

$\% \text{Composition of Pb}=\frac{\text{Atoms of Pb}}{\text{Atoms of Pb}+\text{Atoms of Sn}}\times 100$

$\% \text{Composition of Pb}=\frac{1.59\times 10^{22}}{(1.59\times 10^{22})+(4.79\times 10^{23})}\times 100=3.21\%$

and,

$\% \text{Composition of Sn}=\frac{\text{Atoms of Sn}}{\text{Atoms of Pb}+\text{Atoms of Sn}}\times 100$

$\% \text{Composition of Sn}=\frac{4.79\times 10^{23}}{(1.59\times 10^{22})+(4.79\times 10^{23})}\times 100=96.8\%$

Thus, the percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.

6 0

3 years ago

Please help me and thank you

Alex17521 [72]

Answer:

The physical and chemical properties of the product do not match the properties of the reactant.

Explanation:

Chemical change:

The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.

These changes are irreversible

These changes occur due to chemical reactions

These may not be observed with naked eye

Example:

Combustion of fuel or wood: that oil or wood convert into energy, CO2 and ash in case of wood

Boiling of egg: that change the chemical composition of protein in the egg .

The reaction of Hydrogen and oxygen:

H 2 (g) + O 2 (g) -------------------------------------> 2H 2O (l)

The reaction between sugar and oxygen form a product which is different from the reactant that's why it indicate the occurrence of chemical reaction.

While in case of physical changes just state of matter are changed. Properties remain same.

6 0

3 years ago

1 point

yawa3891 [41]

No one can read that

5 0

2 years ago