All categories

3 years ago

What is a chemical off of the periodic table that is sticky

Chemistry

2 answers:

Gre4nikov [31]3 years ago

5 0

maybe <em>BR..........................................................</em>

Alex73 [517]3 years ago

3 0

I think it’s the one that has a Br

You might be interested in

If 9.8g water is used in electrolysis, what is the percent yield if 5.6g of oxygen was

ANEK [815]

Answer:

Approximately $64\%$ .

Explanation:

$\displaystyle \text{Percentage Yield} = \frac{\text{Actual Yield}}{\text{Theoretical Yield}} \times 100\%$

The actual yield of $\rm O_2$ was given. The theoretical yield needs to be calculated from the quantity of the reactant.

Balance the equation for the hydrolysis of water:

$\rm 2\, H_2O \, (l) \to 2\, H_2\, (g) + O_2\, (g)$ .

Note the ratio between the coefficient of $\rm H_2O\, (g)$ and $\rm O_2\, (g)$ :

$\displaystyle \frac{n(\mathrm{O_2\, (g)})}{n(\mathrm{H_2O\, (aq)})} = \frac{1}{2}$ .

This ratio will be useful for finding the theoretical yield of $\rm O_2\, (g)$ .

Look up the relative atomic mass of hydrogen and oxygen on a modern periodic table.

$\rm H$ : $1.008$ .
$\rm O$ : $15.999$ .

Calculate the formula mass of $\rm H_2O$ and $\rm O_2$ :

$M(\mathrm{H_2O}) =2\times 1.008 + 15.999 = 18.015\; \rm g \cdot mol^{-1}$ .

$M(\mathrm{O_2}) =2\times 15.999 = 31.998\; \rm g \cdot mol^{-1}$ .

Calculate the number of moles of molecules in $9.8\; \rm g$ of $\rm H_2O$ :

$\displaystyle n(\mathrm{H_2O}) = \frac{m(\mathrm{H_2O})}{M(\mathrm{H_2O})} = \frac{9.8\; \rm g}{18.015\; \rm g \cdot mol^{-1}} \approx 0.543991\;\rm g \cdot mol^{-1}$ .

Make use of the ratio $\displaystyle \frac{n(\mathrm{O_2\, (g)})}{n(\mathrm{H_2O\, (aq)})} = \frac{1}{2}$ to find the theoretical yield of $\rm O_2$ (in terms of number of moles of molecules.)

$\begin{aligned} n(\mathrm{O_2}) &= \displaystyle \frac{n(\mathrm{O_2\, (g)})}{n(\mathrm{H_2O\, (aq)})} \cdot n(\mathrm{H_2O}) \\ &\approx \frac{1}{2} \times 0.543991\; \rm mol \approx 0.271996\; \rm mol \end{aligned}$ .

Calculate the mass of that approximately $0.271996\; \rm mol$ of $\rm O_2$ (theoretical yield.)

$\begin{aligned}m(\mathrm{O_2}) &= n(\mathrm{O_2}) \cdot M(\mathrm{O_2}) \\ &\approx 0.271996\; \rm mol \times 31.998\; \rm g \cdot mol^{-1} \approx 8.70331 \; \rm g \end{aligned}$ .

That would correspond to the theoretical yield of $\rm O_2$ (in term of the mass of the product.)

Given that the actual yield is $5.6\; \rm g$ , calculate the percentage yield:

$\begin{aligned}\text{Percentage Yield} &= \frac{\text{Actual Yield}}{\text{Theoretical Yield}} \times 100\% \\ &\approx \frac{5.6\; \rm g}{8.70331\; \rm g} \times 100\% \approx 64\%\end{aligned}$ .

4 0

2 years ago

Predict the sign of the entropy change of the system for each of the following reactions.

storchak [24]

Answer :

(a) The entropy change will also decreases.

(b) The entropy change will also increases.

(c) The entropy change will also decreases.

(d) The entropy change will also increases.

Explanation :

Entropy : It is defined as the measurement of randomness or disorderedness in a system.

The order of entropy will be,

As we are moving from solid state to liquid state to gaseous state, the entropy will be increases due to the increase in the disorderedness.

As we are moving from gaseous state to liquid state to solid state, the entropy will be decreases due to the decrease in the disorderedness.

(a) $N_2(g)+3H_2(g)\rightarrow 2NH_3(g)$

In this reaction, the randomness of reactant molecules are more and as we move towards the formation of product the randomness become less that means the degree of disorderedness decreases. So, the entropy change will also decreases.

(b) $CaCO_3(s)\rightarrow CaO(s)+CO_2(g)$

In this reaction, the randomness of reactant molecules are less and as we move towards the formation of product the randomness become more that means the degree of disorderedness increase. So, the entropy change will also increases.

(c) $3C_2H_2(g)\rightarrow C_6H_6(g)$

In this reaction, 3 mole of gaseous $C_2H_2$ react to give 1 mole of gaseous $C_6H_6$ that means randomness become less that means the degree of disorderedness decreases. So, the entropy change will also decreases.

(d) $Al_2O_3(s)+3H_2(g)\rightarrow 2Al(s)+3H_2O(g)$

In this reaction, the number of moles of gases are same on both side of the reaction but 1 mole of solid $Al_2O_3$ react to give 2 moles of solid aluminium that means randomness become more that means the degree of disorderedness increases. So, the entropy change will also increases.

5 0

3 years ago

Can someone please help me please

GaryK [48]

Liquids have more kinetic energy in their particles compared to solids. this allows the particles to move more freely, hence why they are fluids

Liquids diffuse from a region of high concentration to a region of low concentration, until equilibrium is reached

When heat is applied the particles gain more kinetic energy so they now have enough energy to overcome the bonds holding them in the liquid. this means they can evaporate off

8 0

3 years ago

How are physical and<br>chemical changes different?

astra-53 [7]

Physical changes happen when you do/mix something that can be reversed. Best example is ripping a paper, you can just tape it back together so it is just an observable thing that changes, which is a physical change. Chemical changes happen when you mix things and they make a new substance and can’t be reversed. The best example of this is the Statue of Liberty, which changed in color due to the chemical change between the oxygen and copper, which created a new substance (rust) which made it green instead of copper.
Sorry for the long answer but hope this helps!

5 0

3 years ago

Which of the following will dissociate into the largest number of ions in solution?

Svetlanka [38]

Answer:D

Explanation:

4 0

3 years ago