All categories

4 years ago

How do you find the percent yield of a chemical reaction?

2 answers:

8 0

To express the efficiency of a reaction, you can calculate the percent yield using this formula: %yield = (actual yield/theoretical yield) x 100. A percent yield of 90% means the reaction was 90% efficient, and 10% of the materials were wasted (they failed to react, or their products were not

Eva8 [605]4 years ago

7 0

Answer:divided and multiple by 100

Explanation:

You might be interested in

He pka values of a compound with two ionizable groups are pk1 = 4.10 and pk2 between 7 and 10. a biochemist has 10 ml of a 1.0 m

lyudmila [28]

For the reaction of weak acid:

$HA\rightleftharpoons H^{+}+A^{-}$

The Henderson-hasselbalch equation is:

$pH = pk_a+ log \frac{[A^{-}]}{[HA]}$

The concentration ratio at $pk_1$ is:

$pH = pk_1+ log \frac{[A^{-}]}{[HA]}$

Substituting the values:

$3.2 = 4.1 + log \frac{[A^{-}]}{[HA]}$

$log \frac{[A^{-}]}{[HA]} = - 0.9$

$\frac{[A^{-}]}{[HA]} = 0.126$

Now, for calculating the pk_2 value:

$pH = pk_2+ log \frac{[A^{-}]}{[HA]}$

$8 = pk_2+ log(0.126)$

$pk_2 = 8.9$

Thus, $pk_2 = 8.9$ .

5 0

3 years ago

Please tell if my answer is right or wrong.

xxTIMURxx [149]

Change the places of 'acts against the motion of an object' and 'causes an object to change speed or direction'

5 0

3 years ago

A jeweler guarantees that a piece of jewelry is at least 95% gold, by mass. You consider buying a piece of gold jewelry that wei

ELEN [110]

The density of the sample is:
Density = mass / volume
Density = 9.85 / 0.675
Density = 14.6 g/cm³

If the sample has 95% gold, and 5% silver, its density should be:
0.95 x 19.3 + 0.05 x 10.5
Theoretical density = 18.9 g/cm³

The difference in theoretical and actual densities is very large, making it likely that the jeweler was not telling the truth.

8 0

4 years ago

You place a mass of 250 grams on the measurement tray of a triple beam balance and then set the rider on the 500 gram beam to th

Gala2k [10]

Answer:

<u>The pointer will not be lined up with the zero mark; it will be above the zero mark.</u>

Explanation:

Althoug the list of statements is not provided, you can assure that the pointer will not be lined up with the zero mark, but above the zero mark.

A <em>triple beam balance</em> is very precise instrument, of common use in most labs, used to measure masses. It has three beams. Each beam works for different precisions and mass increments. One beam measures 1 g increments, other beam measures 10 g increments, and the other one 100 g increments.

If you place a mass of 250 grams on the measurement tray, then the weight will be balanced in the beams with 200 grams in the beam that reads increments of 100 g and 50 grams in the beam that reads increments of 10 g. When this is the situation, the weight is completely balanced, and the pointer will be lined up with the zero mark. But this is not the case.

When the rider on the 500 gram beam is set to the 200 gram mark, and the other riders are set to 0 grams, the weight of the mass (250 g) on the tray is greater than the force exerted by the rider on the beam (200 g) and so the tray will be below the level of balance, and the beam will be above the level of balance. The level of balance is indicated when the pointer is lined up with the zero mark.

7 0

3 years ago

When a physical change occurs what cannot be affected as well?

vitfil [10]

Answer:

i believe it is D because the composition does not change

Explanation:

7 0

3 years ago