How can an organism be dead and still be considered a population or a community?

1) When 2.38g of magnesium is added to 25.0cm of 2.27 M hydrochloric acid, hydrogen gas is released.

Andrej [43]

Answer:

a. HCl.

b. 0.057 g.

c. 1.69 g.

d. 77 %.

Explanation:

Hello!

In this case, since the reaction between magnesium and hydrochloric acid is:

$Mg+2HCl\rightarrow MgCl_2+H_2$

Whereas there is 1:2 mole ratio between them.

a) Here, we can identify the limiting reactant as that yielded the fewest moles of hydrogen gas product via the 1:1 and 2:1 mole ratios:

$n_{H_2}^{by\ HCl}=0.025L*2.27\frac{molHCl}{1L}*\frac{1molH_2}{2molHCl} =0.0284molH_2\\\\n_{H_2}^{by\ Mg}=2.38gMg*\frac{1molMg}{24.3gMg}*\frac{1molH_2}{1molMg}=0.0979molH_2$

Thus, since hydrochloric yields fewer moles of hydrogen than magnesium, we realize it is the limiting reactant.

b) Here, we use the molar mass of gaseous hydrogen (2.02 g/mol) to compute the mass:

$m_{H_2}=0.0284molH_2*\frac{2.02gH_2}{1molH_2}=0.057gH_2$

c) Here, we compute the mass of magnesium associated with the yielded 0.0248 moles of hydrogen:

$m_{Mg}^{reacted}=0.0284molH_2*\frac{1molMg}{1molH_2}*\frac{24.3gMg}{1molMg} =0.690gMg$

Thus, the mass of excess magnesium turns out:

$m_{Mg}^{excess}=2.38g-0.690g=1.69gMg$

d) Finally, we compute the percent yield, considering 0.044 g is the actual yield and 0.057 g the theoretical yield:

$Y=\frac{0.044g}{0.057g} *100\%\\\\Y=77\%$

Best regards!

8 0

3 years ago

The temperature inside your freezer is 0 degrees Celsius. You place a balloon with an initial temperature of 30 degrees C and a

blsea [12.9K]

Answer:

V=0.68L

Explanation:

For this question we can use

V1/T1 = V2/T2

where

V1 (initial volume )= 0.75 L

T1 (initial temperature in Kelvin)= 303.15

V2( final volume)= ?

T2 (final temperature in Kelvin)= 273.15

Now we must rearrange the equation to make V2 the subject

V2= (V1/T1) ×T2

V2=(0.75/303.15) ×273.15

V2=0.67577931717

V2= 0.68L

4 0

3 years ago

What is the chemical formula for hydrogen peroxide?

Anon25 [30]

Chemical formula is H2O2

7 0

3 years ago

How much 2.0 M phenylmagnesium chloride solution is needed if adding 2.9 mmol of Grignard reagent to a reaction? Your answer sho

Vladimir [108]

Answer:

1,45 mL

Explanation:

The Grignard reaction is a very important organometallic chemical reaction where the Grignard reagent ( alkyl, vinyl, or aryl-magnesium halides) acts as nucleophile in order to the formation of Carbon-Carbon bonds.

In the problem, the phenylmagnesium chloride is the grignard reagent. The volume of 2.0 M phenylmagnesium chloride solution you need to add 2.9 mmol is:

2,9 mmol × $\frac{1mL}{2,0mM}$ = 1,45 mL

I hope it helps!

3 0

3 years ago

Which statement describes what it means for a planet’s orbit to be elliptical?(1 point)

sesenic [268]

Using the concepts of ellipse and the universal law of gravitation it can be found that the correct answer is:

a) The planet’s path around the sun is not a perfect circle and is shaped like an oval.

The universal gravitational law establishes that the force between two bodies is proportional to their mass and inversely proportional to the square of their distance, when one of the bodies has much greater mass than the other, the body with greater mass experiences less rotational acceleration.

In the case of the sun and the planet, the sun is many orders of magnitude more massive than the planets, therefore, it is almost fixed in the center and the lighter planets rotate around it, where the sun is in the focus of the ellipse orbit.

In the special case that the two foci coincide, there is a circular movement, but the most general is that there is some separation between the foci, so the movement is elliptical with the sun located in one of the foci.

Let's analyze the claims of this exercise

a) True. When the orbit is not a perfect circle, you have an elliptical orbit, this is the most common case.

b) False. The axis of the planet has no effect on the orbit, it affects the intensity of the radiation that reaches the planets

c) False. Circular motion is a special case of elliptical motion when the two foci coincide

d) False. The axis of the planet influences the intensity of radiation reaching the surface, but not the shape of the orbit of the plant.

Using the concepts of ellipse it can be found that the correct answer is:

a) The planet’s path around the sun is not a perfect circle and is shaped like an oval.

learn more about planetary motion here:

brainly.com/question/4978861

3 0

3 years ago