Which element is a noble gas? A. W B. Ar C. N D. Er

Which of the following is altered by a catalyst?

Vika [28.1K]

In chemistry, a catalyst can speed up the reaction (or make it initiate easier) by altering the activation energy, lowering it enough to allow the reactants to react more easily. Some negative catalysts or inhibitors can do the same by increasing the activation energy.

4 0

2 years ago

Consider the reaction. 2 Pb ( s ) + O 2 ( g ) ⟶ 2 PbO ( s ) An excess of oxygen reacts with 451.4 g of lead, forming 367.5 g of

Art [367]

Answer : The percent yield of the reaction is, 75.6 %

Solution : Given,

Mass of Pb = 451.4 g

Molar mass of Pb = 207 g/mole

Molar mass of PbO = 223 g/mole

First we have to calculate the moles of Pb.

$\text{ Moles of }Pb=\frac{\text{ Mass of }Pb}{\text{ Molar mass of }Pb}=\frac{451.4g}{207g/mole}=2.18moles$

Now we have to calculate the moles of $PbO$

The balanced chemical reaction is,

$2Pb(s)+O_2(g)\rightarrow 2PbO(s)$

From the reaction, we conclude that

As, 2 mole of $Pb$ react to give 2 mole of $PbO$

So, 2.18 mole of $Pb$ react to give 2.18 mole of $PbO$

Now we have to calculate the mass of $PbO$

$\text{ Mass of }PbO=\text{ Moles of }PbO\times \text{ Molar mass of }PbO$

$\text{ Mass of }PbO=(2.18moles)\times (223g/mole)=486.1g$

Theoretical yield of $PbO$ = 486.1 g

Experimental yield of $PbO$ = 367.5 g

Now we have to calculate the percent yield of the reaction.

$\% \text{ yield of the reaction}=\frac{\text{ Experimental yield of }PbO}{\text{ Theoretical yield of }PbO}\times 100$

$\% \text{ yield of the reaction}=\frac{367.5g}{486.1g}\times 100=75.6\%$

Therefore, the percent yield of the reaction is, 75.6 %

3 0

3 years ago

For each of the following compounds, write the symbols of the ions in the compound, and the number of each ion in the molecule o

Kay [80]

Ca^2+ and I^-
Na+ and Co3^2-
Ga^3+ and ClO3
Cu^2+ and F-
NH4^- and PO4^3-
Fe2+ and (SO4)^2-
Mg2+ and NO3^-
NH4^+ and NO2^-
K^+ and (C2H3O2)^- {C2H3O2 is acetate}
Na^+ and Cr2O7^2-

8 0

2 years ago

Select the statements that correctly describe a buffer. a) An acid added to the buffer solution reacts with the weak base of the

Tom [10]

Answer:

(B.) The pH of a buffer solution is determined by the ratio of the concentration of conjugate base to the concentration of strong acid.
(C.) A buffer is generally made up of a weak acid and its conjugate base. 
(D.) The pH of a buffer solution does not change significantly when any amount of a strong acid is added.

Explanation:

A buffer is solution which resists change in pH upon addition of either acids or bases.

The pH of a buffer is calculated by the ratio of the concentration of base to concentration of acid. The weak acid and conjugate base have a Ka similar to the pH desired.

3 0

2 years ago

4. Which metals will be able to reduce copper ions in solution?

topjm [15]

4. The metals that would be able to reduce copper ions in solution would be hydrogen(H), lead(Pb), tin(Sb), nickel(Ni), iron(Fe), zinc(Zn), aluminum(Al), Magnesium(Mg), sodium(Na), calcium(Ca), potassium(K), and lithium(Li).

5. If you had a house with both copper- and zinc-galvanized iron water pipes,zinc would be desirable because A metal that is easily oxidized would rust more readily.

3 0

2 years ago