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3 years ago

HELP ASAP

Chemistry

1 answer:

Bezzdna [24]3 years ago

5 0

A. I think sorry if it’s wrong

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Please help me, I am struggling please help

saw5 [17]

Answer:

Colors are seen by burning of metal salts, for example Sodium chloride makes yellow frame.
It is very common for fireworks to contain Aluminum, Iron, Steal, Zinc or the Magnesium’s dust to create bright light.

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3 years ago

Cirrus clouds form at a

sergey [27]

H > 6,000
height greater than 6,000

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3 years ago

A 1.50 L buffer solution is 0.250 M in HF and 0.250 M in NaF. Calculate the pH of the solution after the addition of 0.100 moles

alexgriva [62]

Answer : The pH of the solution is, 3.41

Explanation :

First we have to calculate the moles of $HF$ .

$\text{Moles of HF}=\text{Concentration of HF}\times \text{Volume of solution}$

$\text{Moles of HF}=0.250M\times 1.50L=0.375mol$

Now we have to calculate the value of $pK_a$ .

The expression used for the calculation of $pK_a$ is,

$pK_a=-\log (K_a)$

Now put the value of $K_a$ in this expression, we get:

$pK_a=-\log (6.8\times 10^{-4})$

$pK_a=4-\log (6.8)$

$pK_a=3.17$

The reaction will be:

$HF+OH^-\rightleftharpoons F^-+H_2O$

Initial moles 0.375 0.100 0.375

At eqm. (0.375-0.100) 0 (0.375+0.100)

= 0.275 = 0.475

Now we have to calculate the pH of solution.

Using Henderson Hesselbach equation :

$pH=pK_a+\log \frac{[Salt]}{[Acid]}$

$pH=pK_a+\log \frac{[F^-]}{[HF]}$

Now put all the given values in this expression, we get:

$pH=3.17+\log [\frac{(\frac{0.475}{1.50})}{(\frac{0.275}{1.50})}]$

$pH=3.41$

Thus, the pH of the solution is, 3.41

8 0

3 years ago

You do an experiment in which you need 0.5 moles of tyrosine (C9H11NO3). How many grams must you weigh out?

Yuki888 [10]

Answer: a) 90.5g

b) 33.6 L

Explanation:-

Molar mass of tyrosine $(C_9H_{11}NO_3)$ = 181 g/mol

According to Avogadro's law, 1 mole of every substance weighs equal to its molar mass.

1 mole of tyrosine $(C_9H_{11}NO_3)$ weighs = 181 g/mol

0.5 moles of tyrosine $(C_9H_{11}NO_3)$ weigh $=\frac{181g/mol}{1}\times 0.5moles=90.5g$

b) According to Avogadro's law, 1 mole of an ideal gas occupies 22.4 Liters at Standard conditions of temperature and pressure (STP).

1 mole of gas at STP occupy = 22.4 L

1.5 moles of gas at STP occupy = $\frac{22.4L}{1}\times 1.5=33.6L$

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3 years ago

Which of the following elements has the smallest atomic radius?

erastova [34]

Answer:

Fluroine

Explanation:

6 0

2 years ago

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