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How many milliliters of 5.0 M NaOH are needed to exactly neutralize 40. milliliters of 2.0 M HCl?

zubka84 [21]

Answer:

16mL

Explanation:

Using the following formula;

CaVa = CbVb

Where;

Where

Ca = concentration/molarity of acid (M)

Va = volume of acid (mL)

Cb = concentration/molarity of base (M)

Vb = volume of base (mL)

According to the information provided in this question;

Ca (HCl) = 2M

Cb (NaOH) = 5M

Va (HCl) = 40mL

Vb (NaOH) = ?

Using CaVa = CbVb

Vb = CaVa/Cb

Vb = 2 × 40/5

Vb = 80/5

Vb = 16mL

5 0

3 years ago

What is the pressure of 0.33 moles of nitrogen gas, if its volume is 15.0 L at –25.0oC?

musickatia [10]

Using the ideal gas law PV =nRTPV=nRT , we find that the pressure will be P =\frac{nRT}{V}P=

V

nRT

. Then, we'll substitute and find the pressure, using T = -25 °C = 248.15 K and R = 0.0821 \frac{atm\cdot L}{mol \cdot K}

mol⋅K

atm⋅L

:

P =\frac{nRT}{V} = \frac{(0.33\,\cancel{mol})(0.0821\frac{atm\cdot \cancel{L}}{\cancel{mol \cdot K}})(248.15\,\cancel{K})}{15.0\,\cancel{L}} = 0.4482\,atmP=

V

nRT

=

15.0

L

(0.33

mol

)(0.0821

mol⋅K

atm⋅

L

)(248.15

K

)

=0.4482atm

In conclusion, the pressure of this gas is P=0.4482 atm.

Reference:

Chang, R. (2010). Chemistry. McGraw-Hill, New York.

3 0

2 years ago

A pure substance is found to contain 53.7% fluorine and 46.3% xenon by mass. What is the empirical formula of this substance?

evablogger [386]

Answer: XF8

Explanation:

Empirical Formular shows the simplest ratio of elements in a compound.

Xe = 46.3% F = 53.7%

Divide the percentage composition of each element by the atomic mass.

Xe = 46.3/ 131.3 F= 53.7/ 19

= 0.353( approx) = 2.826 (approx)

Divide through with the smallest of the answers gotten in previous step.

Xe = 0.353 / 0.353 F = 2.826/ 0.353

= 1 = 8.0

Empirical formular = XF8

3 0

3 years ago

Use the following equation to answer the questions below:

Gala2k [10]

Explanation:

The equation of the reaction is given as;

Be + 2HCl → BeCl2 + H2

What is the mass of beryllium required to produce 25.0g of beryllium chloride?

1 mol of Be produces 1 mol of BeCl2

Converting to mass;

Mass = Molar mass * Number of moles

9.01g of Be produces 79.92g of BeCl2

xg of Be produces 25g of BeCl2

Solving for x;

x = 25 * 9.01 / 79.92

x = 2.82 g

What is the mass of hydrochloric acid required to produce 25.0g of beryllium chloride? g

Converting 25.0g of beryllium chloride to moles;

Number of moles = Mass / Molar mass

Number of moles = 25 / 79.92 = 0.3128 mol

2 mol of HCl produces 1 mol of BeCl2

x mol of HCl would produce 0.3128 mol of BeCl2

solving for x;

x = 0.3128 * 2 = 0.6256 mol

Converting to mass;

Mass = 0.6256 * 36.5 = 22.83 g

What is the mass of hydrogen gas produced when 25.0g of beryllium chloride is also produced? g

25g of BeCl2 = 0.3128 mol of BeCl2

From the equation;

1 mol of H2 is produced alongside 1 mol of BeCl2

This means;

0.3128 mol of H2 would also be produced alongside 0.3128 mol of BeCl2

Mass = Number of moles * Molar mass

Mass = 0.3128mol * 2.0159 g/mol = 0.6306 g

3 0

3 years ago

What subatomic particle was discovered with the use of a cathode-ray tube

slamgirl [31]

Answer:

The correct answer is: Electron

Explanation:

Electron (e⁻) is the negatively charged subatomic particle that has an electric charge of -1e (−1.6022 ×10⁻¹⁹ C). It was discovered by the English physicist, Sir Joseph John Thomson (J. J. Thomson) in the year 1897 by the cathode ray experiment.

In the cathode ray experiment, Sir Joseph John Thomson used the cathode ray tubes to conclude the presence of negatively charged small subatomic particle, known as electrons, in all atoms.

3 0

3 years ago