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3 years ago

True or False ... In a chemical change, a new substance is formed.

Chemistry

1 answer:

nikitadnepr [17]3 years ago

7 0

The answer is true the answer has to be 20 words long so true true true true true true

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Give the name and symbol of the prefixes used with SI units to indicate multiplication by the following exact quantites.

Bingel [31]

Answer:

A. Kilo , K, multiplication by 1000

B. Centi, c

C. Deci, d

D. Mili, m

E. Mega, M

F. Micro, u

7 0

3 years ago

3. 25. The temperatures favorable for the growth of most bacteria are

kvasek [131]

about the same as for humans

Explanation:

This is why most bacteria, during research in labs, are incubated at 37 degrees centigrade, about the same as human body temperature. In addition, harmful and beneficial bacteria thrive in the human body due to the favorable temperatures for growth and reproduction. To try and fight an infection, the body also tries to raise the body temperatures above the optimal for the bacteria growth (the reason one has a fever in case of infection).

6 0

3 years ago

Is cotton yarn a natural resource?

Natalija [7]

Yes, because cotton is a plant and then the cotton is then made into a ball of yarn.

8 0

3 years ago

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

Ethyl butyrate, CH3CH2CH2CO2CH2CH3, is an artificial fruit flavor commonly used in the food industry for such flavors as orange

SIZIF [17.4K]

Answer:

A. 10.0 grams of ethyl butyrate would be synthesized.

B. 57.5% was the percent yield.

C. 7.80 grams of ethyl butyrate would be produced from 7.60 g of butanoic acid.

Explanation:

$CH_3CH_2CH_2CO_2H(l)+CH_2CH_3OH(l)+H^+\rightarrow CH_3CH_2CH_2CO_2CH_2CH_3(l)+H_2O(l)$

Moles of butanoic acid = $\frac{7.60 g}{88 g/mol}=0.08636 mol$

According to reaction ,1 mole of butanoic acid gives 1 mol of ethyl butyrate,then 0.08636 mol of butanoic acid will give :

$\frac{1}{1}\times 0.08636 mol=0.08636 mol$ of ethyl butyrate

Mass of 0.08636 moles of ethyl butyrate =

0.08636 mol × 116 g/mol = 10.0 g

Theoretical yield = 10.0 g

Experimental yield = ?

Percentage yield of the reaction = 100%

$Yield\%=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

$100\%=\frac{\text{Experimental yield}}{10.0 g}\times 100$

Experimental yield = 10.0 g

10.0 grams of ethyl butyrate would be synthesized.

Theoretical yield of ethyl butyrate = 10.0 g

Experimental yield ethyl butyrate = 5.75 g

Percentage yield of the reaction = ?

$Yield\%=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

$=\frac{5.75 g}{10.0 g}\times 100=57.5\%$

57.5% was the percent yield.

Moles of butanoic acid = $\frac{7.60 g}{88 g/mol}=0.08636 mol$

According to reaction ,1 mole of butanoic acid gives 1 mol of ethyl butyrate,then 0.08636 mol of butanoic acid will give :

$\frac{1}{1}\times 0.08636 mol=0.08636 mol$ of ethyl butyrate

Mass of 0.08636 moles of ethyl butyrate =

0.08636 mol × 116 g/mol = 10.0 g

Theoretical yield = 10.0 g

Experimental yield = ?

Percentage yield of the reaction = 78.0%

$Yield\%=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

$78.0\%=\frac{\text{Experimental yield}}{10.0 g}\times 100$

Experimental yield = 7.80 g

7.80 grams of ethyl butyrate would be produced from 7.60 g of butanoic acid.

8 0

3 years ago