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3 years ago

Why is biodiversity important?

Chemistry

2 answers:

VARVARA [1.3K]3 years ago

3 0

A or the first answer

Cerrena [4.2K]3 years ago

3 0

Answer: a, or it makes an ecosystem stable.

ecosystems need biodiversity to make it stronger, or stable.

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Reaction of 0.028 g of magnesium with excess hydrochloric acid generated 31.0 mL of hydrogen gas. The gas was collected by water

MA_775_DIABLO [31]

Explanation:

(a) It is given that magnesium is reacted with hydrochloric acid and the hydrogen evolved is collected at top. This means that hydrochloric acid will be present in a solution (HCl + Water) and the solvent will be water.

Due to evaporation some amount of water will have evaporated and would be present in vapor phase. Therefore, when the reaction occurs only hydrogen will not be present in vapor phase but, will be accompanied by water vapors as well .

Hence, Dalton's law the total pressure of the system will be sum of pressure exerted by hydrogen gas and pressure exerted by water vapors .

Let us assume that the partial pressure of hydrogen gas be " $P_H_{2}$ "

And, the partial pressure of water will be nothing but the vapor pressure of water,

Vapor pressure of water = $P_{water}$

= 19.8 mm Hg

Total pressure of the system = 746 mm Hg

Total pressure = $P_H_{2} + P_{water}$

746 = $P_H_{2}$ + 19.8

or, $P_H_{2}$ = 746-19.8

= 726.2 mm Hg

Hence, partial pressure of hydrogen gas is 726.2 mm Hg.

(b) To calculate volume at STP, we will first calculate at $22^{o}C$ and 726.2 mm Hg and than convert it to STP conditions.

Therefore, to calculate volume at $22^{o}C$ and 726.2 mm Hg we will make use of ideal gas law as follows.

P = 726.2 mm Hg

= $\frac{726.2}{760}$

= 0.955 atm

T = $22^{o}C$

= 22+273.15 = 295.15 K

V = 31 ml = $31 \times 10^{-3}$ Litre

According to the ideal gas law ,

PV = nRT

where, P = pressure of the system ,

V = volume of the gas

N = number of moles

R = 0.0821 liter atm/mole K

T = Temperature

Hence, putting the given values into the above formula as follows.

$0.955 \times 31 \times 10^{-3} = N \times 0.0821 \times 295.15$

N = $1.222 \times 10^{-3}$ moles

Now, the moles of hydrogen won't change. Therefore, let us calculate volume at STP of $1.222 \times 10^{-3}$ moles of hydrogen.

Now, at STP T = 273.15 K , P = 1 atm and N = $1.222 \times 10^{-3}$ moles

$1 \times V = 1.222 \times 10^{-3} \times 0.0821 \times 273.15 K$

V = 0.027398 Litre

= $0.027398 \times 1000$ (as 1 L = 1000 ml)

= 27.398 ml

Therefore, volume of hydrogen at STP is 27.398 ml .

(c) Now, we can write the the reaction for this case as follows.

$Mg + 2HCl \rightarrow MgCl_{2} + H_{2}$

As, weight of magnesium = 0.028 grams

Molar mass of magnesium = 24.3 grams/mole

Number of moles of magnesium = $\frac{mass}{\text{molar mass}}$

= $\frac{0.028}{24.3}$

= $1.15226 \times 10^{-3}$ moles

Since, it can be seen from the reaction that

1 mole of Magnesium = 1 mole of hydrogen

and, moles of hydrogen = $1.15226 \times 10^{-3}$ moles

= 0.001523 moles

Hence, theoretical number of moles of hydrogen that can be produced from 0.028 grams of Mg is 0.001523 moles

8 0

4 years ago

-Watch the video

Elena-2011 [213]

Answer:

maybe you should watch the video...

we can't help you because we don't have the vid.

Explanation:

7 0

3 years ago

Read 2 more answers

Throughout the reflection, make sure you have a copy of the Student Guide and your data tables. Use the drop-

Inessa05 [86]

Answer:

1) mass and type of material

2) type of material

3) temperature

Explanation:

8 0

2 years ago

What is the mole ratio that can convert from moles of A to moles of B?

kaheart [24]

There is no direct way to convert from the mass of one substance to the mass of another. To convert from one mass (substance A) to another mass (substance B), you must convert the mass of A first to moles, then use the mole-to-mole conversion factor (B/A), then convert the mole amount of B back to grams of B.

8 0

3 years ago

The following questions are about ethyl bromide,n-propyl bromide, isopropyl bromide,t-butyl bromide, & neopentyl bromide

mrs_skeptik [129]

Answer:

a) Watch the attaccment

b) Ethyl bromide is more reactive than n-propyl bromid, and this more than neopentyl bromide. Ethyl bromide has less steric hindrance than the others, to SN2 reactions.

c) t-butyl bromide is more reactive than isopropyl bromide, and this more than ethyl bromide. t-butyl bromide structure stabilize the carbocation, better than the others.

Explanation:

Speed of SN2 reactions depends on steric hindrance, the less hindrance, the most reaction speed, meaning more reactivity. Then, those linear structures are more reactive to SN2 reactions.

In the other hand, speed of SN1 reactions depends on the stability of the carbocation formed. Structure with ramifications can stabilize better the carbocation, these structures are more reactive to SN1 reactions.

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7 0

3 years ago