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4 years ago

How do astronomers explain the formation of the milky way galaxy

1 answer:

3 0

Galaxy Formation. One says that galaxies were born when vast clouds of gas and dust collapsed under their own gravitational pull, allowing stars to form. The other, which has gained strength in recent years, says the young universe contained many small "lumps" of matter, which clumped together to form galaxies.

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Determine the pH of a 5x10^-4 M solution of Ca(OH)2

miss Akunina [59]

Ca(OH)₂ ==> Ca²⁺ + 2 OH-

Ca(OH)₂ is strong Bases

Therefore, the [OH-] equals 5 x 10⁻⁴ M. For every Ca(OH)₂ you produce 2 OH⁻.

pOH = - log[ OH⁻]

pOH = - log [ 5 x 10⁻⁴ ]

pOH = 3.30

pH + pOH = 14

pH + 3.30 = 14

pH = 14 - 3.30

pH = 10.7

hope this helps!

5 0

3 years ago

Explain the relationship between altitude and air pressure

Nataly [62]

Pressure with Height: pressure decreases with increasing altitude. The pressureat any level in the atmosphere may be interpreted as the total weight of the airabove a unit area at any elevation. At higher elevations, there are fewer airmolecules above a given surface than a similar surface at lower levels

8 0

3 years ago

Read 2 more answers

The element X has three naturally occurring isotopes. The masses (amu) and % abundances of the isotopes are given in the table b

denis-greek [22]

Answer:

220.42098 amu

Explanation:

(220 .9 X .7422) + (220 X .0.1278) + (218.1 X 0.13) = 220.42098 amu

These are weighted averages.

So, we will take mass of one and multiply by abundance percentage that is provided and add them together.

In order to calculate the average atomic mass, we have to convert the percentages of abundance to decimals. So, you get

(220 .9 X .7422) + (220 X .0.1278) + (218.1 X 0.13) = 220.42098 amu

6 0

3 years ago

1. The hydrogenation of ethene gas at 298 K shows a decrease in disorder (AS-120.7 J/mol-K) during an exothermic reaction ( Delt

Anna71 [15]

K shows a decrease in disorder (AS = -120.7 J/(mol-K)) during an exothermic reaction (AH' = -136.9 kJ/mol). Determine whether the reaction is spontaneous or ...

8 0

3 years ago

How many liters of hydrogen gas will be produced at STP from the reaction of 7.179×10^23 atoms of magnesium with 54.219g of phos

Alexeev081 [22]

Answer: The volume of hydrogen gas produced will be, 12.4 L

Explanation : Given,

Mass of $H_3PO_4$ = 54.219 g

Number of atoms of $Mg$ = $7.179\times 10^{23}$

Molar mass of $H_3PO_4$ = 98 g/mol

First we have to calculate the moles of $H_3PO_4$ and $Mg$ .

$\text{Moles of }H_3PO_4=\frac{\text{Given mass }H_3PO_4}{\text{Molar mass }H_3PO_4}$

$\text{Moles of }H_3PO_4=\frac{54.219g}{98g/mol}=0.553mol$

and,

$\text{Moles of }Mg=\frac{7.179\times 10^{23}}{6.022\times 10^{23}}=1.19mol$

Now we have to calculate the limiting and excess reagent.

The balanced chemical equation is:

$3Mg+2H_3PO_4\rightarrow Mg(PO_4)_2+3H_2$

From the balanced reaction we conclude that

As, 3 mole of $Mg$ react with 2 mole of $H_3PO_4$

So, 0.553 moles of $Mg$ react with $\frac{2}{3}\times 0.553=0.369$ moles of $H_3PO_4$

From this we conclude that, $H_3PO_4$ is an excess reagent because the given moles are greater than the required moles and $Mg$ is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $H_2$

From the reaction, we conclude that

As, 3 mole of $Mg$ react to give 3 mole of $H_2$

So, 0.553 mole of $Mg$ react to give 0.553 mole of $H_2$

Now we have to calculate the volume of $H_2$ gas at STP.

As we know that, 1 mole of substance occupies 22.4 L volume of gas.

As, 1 mole of hydrogen gas occupies 22.4 L volume of hydrogen gas

So, 0.553 mole of hydrogen gas occupies $0.553\times 22.4=12.4L$ volume of hydrogen gas

Therefore, the volume of hydrogen gas produced will be, 12.4 L

4 0

3 years ago