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1 year ago

6

A graduated cylinder initially has 32.5 mL of water in it. After a 75.0 g piece of lead (Pb) is added to the graduated cylinder,

the water level rises to the 39.1 mL mark. What is the the volume of the piece of lead.

1 answer:

Mice21 [21]1 year ago

6 0

Answer:

39.1-32.5 and you will find your answer it always like that, you subtract your starting point from your ending point

Explanation:

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Which of the following species is not formed through a termination reaction in the chlorination of methane? Which of the followi

krek1111 [17]

Explanation:

When we add chlorine to a substance or compound then this process is known as chlorination.

For example, a process of chlorination is as follows.

Initiation : $Cl_{2} \overset{light}{\rightarrow} 2Cl*$

where, Cl* is a free radical.

Propagation:

$Cl* + CH_{4} \rightarrow HCl + *CH_{3}$

$CH_{3} + Cl_{2} \rightarrow CH_{3}Cl + Cl*$

Termination:

$2Cl* \rightarrow Cl_{2}$

$Cl* + *CH_{3} \rightarrow CH_{3}Cl$

$2*CH_{3} \rightarrow CH_{3}-CH_{3}$

Thus, we can conclude that out of the given options $H_{2}$ is not formed through a termination reaction in the chlorination of methane.

5 0

2 years ago

When food spoils, it is a chemical reaction. For example, rancid butter is produced when the fat molecules in the butter undergo

Sergio039 [100]

Answer: Decreases the rate of reaction

Remove water from food by dehydration.
Transport food in a refrigerated truck.
Store food in airtight containers.
Store food in a refrigerator after opening.

Does not decrease the rate of reaction

Store food in the open air.
Place food on a warm surface.

Explanation: Dehydration of food excludes water from food which is one of the factor needed by microorganisms for growth, <em>so it decreaese the rate of reaction.</em>

Transporting food in refrigerated trucks lowers the temperature of food and not many microorganisms are active at very low temperatures, so it <em>decreases the rate of reaction.</em>

Storing food in airtight containers excludes air which is one of the factors required for microbial activity, so <em>it decreases reaction rate.</em>

Storing food in refrigerators after opening also <em>lowers the temperature of food and hence the the rate of microbial activit</em>y.

Storing food in the open air <em>does not decrease microbial activity</em> instead it provides microorganisms with the favorable conditions for their activity such as air and water from water vapor in the air.

Placing food on a warm surface <em>does not decrease rate of reaction</em> because microorganisms are very active in warm and humid environments.

4 0

2 years ago

Acetone is one of the most important solvents in organic chemistry. It is used to dissolve everything from fats and waxes to air

Yanka [14]

Answer: a. 79.6 s

b. 44.3 s

c. 191 s

Explanation:

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process

a) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

$t_{\frac{1}{2}}=\frac{0.693}{k}$

$t_{\frac{1}{2}}=\frac{0.693}{8.7\times 10^{-3}s^{-1}}=79.6s$

b) for completion of 32% of reaction

$t=\frac{2.303}{k}\log\frac{100}{100-32}$

$t=\frac{2.303}{8.7\times 10^{-3}}\log\frac{100}{68}$

$t=44.3s$

c) for completion of 81 % of reaction

$t=\frac{2.303}{k}\log\frac{100}{100-81}$

$t=\frac{2.303}{8.7\times 10^{-3}}\log\frac{100}{19}$

$t=191s$

4 0

1 year 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:

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

A

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.

B

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.

C

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

2 years ago

The reaction between hydrogen gas and chlorine gas produces hydrogen chloride according to the following equation: H2(g) + Cl2(g

Andreyy89

Answer:

The enthalpy of reaction is -185 kJ

Explanation:

To get the reaction:

H₂(g) + Cl₂(g) → 2 HCl(g)

you must follow the following steps:

<em>1) Reactive molecules must break their bonds to obtain their atoms.</em>

H₂(g) → 2 H(g)

Cl₂(g) → 2 Cl(g)

Bond energy (or enthalpy) is the energy required to break one mole of bonds of a gaseous substance. In the case of diatomic molecules with a single bond, it corresponds to the energy necessary to dissociate 1 mole of said substance in the atoms that form it.

Whenever you want to break links you must supply energy, so the link enthalpy will have positive values; while when a mole of bonds is formed energy is released and the bond enthalpy of this process will be negative.

In this case you will then have:

H₂(g) → 2 H(g) ΔH=436 kJ/mol

Cl₂(g) → 2 Cl(g) ΔH=243 kJ/mol

So the total energy needed to break all the bonds is:

ΔH=1 mol*436 kJ/mol +1 mol* 243 kJ/mol= 679 kJ

2) The atoms that were obtained in the break of the bonds must be combined to obtain the product.

2 H (g) + 2 Cl (g) → 2 HCl (g)

Being the single bond energy for one mole of 431 kJ H-Cl bonds and considering that two moles of H-Cl bonds are formed, the ΔH is:

ΔH = -2 moles* (432 kJ/mol) = -864 kJ

As mentioned, when a mole of bonds is formed energy is released, the bond enthalpy of this process will be negative. So the formation of HCl is negative.

Hess's law states that the energy change in an overall chemical reaction is equal to the sum of the energy changes in the individual reactions comprising it. So:

ΔHtotal= -864 kJ + 679 kJ

ΔHtotal= -185 kJ

<u><em>The enthalpy of reaction is -185 kJ</em></u>

3 0

2 years ago