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2 years ago

How can you separate a mixture of dry materials

1 answer:

6 0

Any substance that is not a mixture is a pure substance. When colored watercolors are applied to paper, sometimes the colors in the ink separate. This technique is called chromatography

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ithium metal reacts with water to give lithium hydroxide and hydrogen gas. if 75.5 mL of hydrogen gas is produce at STP, what is

Galina-37 [17]

The reaction equation may be written as:
2Li + 2H₂O → 2LiOH + H₂

A single mole of gas occupies 22,400 ml of gas at STP. Therefore, the moles of hydrogen gas are
75.5 / 22,400 = 0.0034 mol
According to the equation, the moles of lithium are twice that of hydrogen gas; thus,
0.0034 x 2 = 0.0068 mol

The mass of lithium is given by:
mass = moles x atomic mass
mass = 0.0068 x 6.9
mass = 0.047 grams

6 0

2 years ago

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When 20.00 mL of an unknown monoprotic acid is titrated with 0.125 M NaOH, it takes 15.00 mL to reach the endpoint. What is the

ohaa [14]

Answer:

About 0.0940 M.

Explanation:

Recall that NaOH is a strong base, so it dissociates completely into Na⁺ and OH⁻ ions. Because the acid is monoprotic, we can represent it with HA. Thus, the reaction between HA and NaOH is:

$\displaystyle \text{HA}_\text{(aq)} + \text{OH}^-_\text{(aq)} \longrightarrow \text{H$_2$O}_\text{($\ell$)} + \text{A}^-_\text{(aq)}$

Using the fact that it took 15.00 mL of NaOH to reach the endpoint, determine the number of HA that was reacted with:

$\displaystyle \begin{aligned} 15.00\text{ mL} &\cdot \frac{0.125\text{ mol NaOH}}{1\text{ L}} \cdot \frac{1\text{ L}}{1000\text{ mL}} \\ \\ &\cdot \frac{1\text{ mol OH}^-}{1\text{ mol NaOH}} \cdot \frac{1\text{ mol HA}}{1\text{ mol OH}^-}\\ \\ & = 0.00188\text{ mol HA}\end{aligned}$

Therefore, the molarity of the original solution was:

$\displaystyle \left[ \text{HA}\right] = \frac{0.00188\text{ mol}}{20.00\text{ mL}} \cdot \frac{1000\text{ mL}}{1\text{ L}} = 0.0940\text{ M}$

In conclusion, the molarity of the unknown acid is about 0.0940 M.

3 0

2 years ago

1. What Volume of HCl is generated if 3.44 g of Cl2 are reacted at STP? 2. What volume does 4.87 mol of Kr have at STP? 3. What

IgorLugansk [536]

Answer:

1. 2.17 dm3 VOLUME OF HCl IS PRODUCED WHEN 3.44 g OF Cl2 REACT AT STP

2. 4.87 MOLE OF Kr AT STP CONTAINS 109.088 dm3 .

3. THE PRESSURE WHEN 3.44 g OF Cl2 are reacted at 4.55 L AT 455 K IS 0.77 atm

Explanation:

1 Volume of HCl if 3.44 g of Cl2 are reacted at STP?

Equation for the reaction:

H2 + Cl2 ---------> 2HCl

1 mole of Cl2 reacts to form 2 mole of HCl

At STP, 1 mole of a gas is equal to the molar mass of the gas sample

35.5 * 2 g of Cl2 reacts to form 2 mole of HCl

3.44 g of Cl2 will react to form ( 3.44 * 2 / 71 ) mole of HCl

= 0.0969 mole of HCl

1 mole of HCl = 22.4 dm3

0.0969 mole of HCl = ( 22.4 * 0.0969 / 1)

= 2.17056 dm3

The volume of HCl is 2.17 dm3 when 3.44 g of Cl2 are reacted at STP.

2. What volume does 4.87 mol of Kr have at STP?

1 mole of a substance is 22.4 dm3 of the sample

1 mole of Kr = 22.4 dm3

4.87 mole of Kr = 4.87 * 22.4

= 109.088 dm3

4.87 mole of Kr at STP contains 109.088 dm3 volume

3. Whta pressure of HCl is generated if 3.44 g of Cl2 are reacted at 4.55 L at 455 K

Using the formula:

PV = nRT

V = 4.55 L

R = 0.082 L atm/ mol K

T = 455 K

m = 3.44 g

n = mass / molar mass

molar mass = ( 1 + 35.5) = 36.5 g/mol

n = 3.44 g / 36.5 g/mol

n = 0.094 mole

P = nRT / V

P = 0.094 * 0.082 * 455 / 4.55

P = 3.50714 / 4.55

P = 0.7708 atm

The pressure of HCl if 3.44 g of Cl2 are reacted at 4.55 L and 455 K is 0.7708 atm.

8 0

2 years ago

Ammonium acetate chemical formula

Dmitry_Shevchenko [17]

Ammonium acetate:

Formula C2H7NO<span>2</span>

3 0

2 years ago

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When the molecules of a gas hit each other do they normally stick or bounce off

Dahasolnce [82]

Since the molecules of a gas are constantly in motion, moving and hitting other gas molecules in all directions of the enclosed container, the molecules transfer a portion of energy through the interaction of other gas particles as they hit, but then bounce off.

8 0

2 years ago

Read 2 more answers