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2 years ago

12-How many elements are in the mixture pictured below? A-7 O B-4 C-3 D-2

Chemistry

2 answers:

STALIN [3.7K]2 years ago

8 0

The answer is 3

The elements are red, black, and blue!

vovikov84 [41]2 years ago

4 0

Answer:

Explanation:

Because you don't count the dots. You count how many colors there are. Which are Blue, Red, and Black.

Hope this helped!

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What volume is occupied by 8.7 g of chlorine gas, Cl2, at 23°C and 1.15 atm pressure

Harrizon [31]

Answer:

V = 5.17L

Explanation:

Mass of gas = 8.7g

T = 23°C = (23 + 273.15)K = 296.15K

P = 1.15 atm

V = ?

R = 0.082atm.L / mol.K

From ideal gas equation

PV = nRT

P = pressure of the gas

V = volume of the gas

n = no. Of moles

R = ideal gas constant

T = temperature of the gas

no of moles = mass / molar mass

Molar mass of Chlorine = 35.5g / mol

No. Of moles = 8.7 / 35.5

No. Of moles = 0.245 moles

PV = nRT

V = nRT / P

V = (0.245 * 0.082 * 296.15) / 1.15

V = 5.9496 / 1.15

V = 5.17L

The volume of the gas is 5.17L

4 0

3 years ago

Which of the following is a true statement?

sergejj [24]

Answer:

Explanation:

Wind is geological therefore it is geological weathering

5 0

2 years ago

A 35.0-ml sample of 0.20 m lioh is titrated with 0.25 m hcl. What is the ph of the solution after 23.0 ml of hcl have been added

kiruha [24]

<h3><u>Answer;</u></h3>

pH = 12.33

<h3><u>Explanation;</u></h3>

The equation of reaction is :

LiOH(aq) + HCl(aq) --> LiCl(aq) + H2O(l)

Reactants left after the titrant is added;

Total Moles LiOH;

= 0.035L LiOH × (0.2moles/L)

= 0.007moles of LiOH

Moles of HCl;

= 0.023L HCl × (0.25moles/L)

= 0.00575moles HCl is the limiting reagent

Reacting amount of moles of LiOH;

= 0.0575 moles HCl *(1mole LiOH/1moles HCl)

=0.00575 moles LiOH (reacted)

Moles of LiOH left;

= 0.007moles total - 0.00575moles that react

= .00125 moles of LiOH (left)

LiOH is a strong base, which means that it ionizes completely.

0.00125moles LiOH *(moles/0.058L) = 0.02155M of LiOH

LiOH(aq) --> Li+(aq) + OH-(aq)

[LiOH] = [OH-] = 0.02155 M

pOH = -log[OH-]

pOH = -log(0.02155)

pOH= 1.67

pH = 14 - pOH

pH = 14 - 1.67

pH = 12.33

7 0

3 years ago

A buffer consists of 0.120 M HNO2 and 0.150 M NaNO2 at 25°C. pka of HNO2 is 3.40. a. What is the pH of the buffer? b. What is th

Mashcka [7]

Explanation:

It is known that $K_{a}$ of $HNO_{2}$ = $4.5 \times 10^{-4}$ .

(a) Relation between $K_{a}$ and $pK_{a}$ is as follows.

$pK_{a} = -log (K_{a})$

Putting the values into the above formula as follows.

$pK_{a} = -log (K_{a})$

= $-log(4.5 \times 10^{-4})$

= 3.347

Also, relation between pH and $pK_{a}$ is as follows.

pH = $pK_{a} + log\frac{[conjugate base]}{[acid]}$

= $3.347+ log \frac{0.15}{0.12}$

= 3.44

Therefore, pH of the buffer is 3.44.

(b) No. of moles of HCl added = $Molarity \times volume$

= $11.6 M \times 0.001 L$

= 0.0116 mol

In the given reaction, $NO^{-}_{2}$ will react with $H^{+}$ to form $HNO_{2}$

Hence, before the reaction:

No. of moles of $NO^{-}_{2}$ = $0.15 M \times 1.0 L$

= 0.15 mol

And, no. of moles of $HNO_{2}$ = $0.12 M \times 1.0 L$

= 0.12 mol

On the other hand, after the reaction :

No. of moles of $NO^{-}_{2}$ = moles present initially - moles added

= (0.15 - 0.0116) mol

= 0.1384 mol

Moles of $HNO_{2}$ = moles present initially + moles added

= (0.12 + 0.0116) mol

= 0.1316 mol

As, $K_{a}$ = $4.5 \times 10^{-4}$

$pK_{a} = -log (K_{a})$

= $-log(4.5 \times 10^{-4})$

= 3.347

Since, volume is both in numerator and denominator, we can use mol instead of concentration.

As, pH = $pK_{a} + log \frac{[conjugate base]}{[acid]}$

= 3.347+ log {0.1384/0.1316}

= 3.369

= 3.37 (approx)

Thus, we can conclude that pH after the addition of 1.00 mL of 11.6 M HCl to 1.00 L of the buffer solution is 3.37.

6 0

3 years ago

Which of the following best describes magnetic fields

BigorU [14]

Well the multiple choices for this question would be helpful, but from my own knowledge I would say:

Magnetic fields have north and south magnetic poles.

Magnetic fields have various characteristics which includes; they originate from the north poles and flow towards the south poles, they are exhibited in the form of magnetic field lines. Magnetic fields lines never cross one another,they all have the same strength and seek the path of least resistance between opposite magnetic poles etc.

3 0

2 years ago