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kkurt [141]
3 years ago
6

Which sample contains a total of 6.0 x 1023 molecules? Select one: a. 4.0 g of He b. 14 g of Li c. 80 g of Br2 d. 4.0 g of H2

Chemistry
1 answer:
navik [9.2K]3 years ago
3 0

Answer:

Option a. 4 g of He

Explanation:

6.02×10²³ is the Avogadro's number. The amount of units that corresponds to 1 mol, in this case the units are molecules.

Let's find out which mass corresponds to 1 mol (mass / molar mass)

a. 4g / 4g/mol = 1 mol He

b. 14g / 6.94 g/mol = 2.01 mol Li

c. 80g /159.8 g/mol = 0.5 moles Br₂

d. 4g / 2g/mol = 2 mol H₂

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Explain how metallic bonding causes metals to conduct electricity?
astra-53 [7]
In a metallic bond, atoms of the metal are surrounded by a constantly moving "sea of electrons". This moving sea of electrons enables the metal to conduct electricity and move freely among the ions.
3 0
3 years ago
(a) What is the total volume (in L) of gaseous products, measured at 350°C and 735 torr, when an automobile engine burns 100. g
Anarel [89]

Answer:

Part A

 The volume of the gaseous product  is  V = 787L

Part B

The volume of the the engine’s gaseous exhaust is  V_e = 2178 \ L

Explanation:

Part A

From the question we are told that

    The temperature is  T = 350^oC = 350 +273 =623K

     The pressure is  P = 735 \ torr = \frac{735}{760} =  0.967\ atm

     The of  C_8 H_{18} = 100.0g

The chemical equation for this combustion is

               2 C_8 H_{18}_{(l)} + 25O_2_{(l)} ----> 16CO_2_{(g)} + 18 H_2 O_{(g)}

 The number of moles of  C_8 H_{18} that reacted is mathematically represented as

               n = \frac{mass \ of \  C_8H_{18}  }{Molar \  mass \ of  C_8H_{18} }

The molar mass of  C_8 H_{18} is constant value which is

                  M = 114.23 \ g/mole  

So          n = \frac{100  }{114.23} }

             n = 0.8754 \ moles

The gaseous product in the reaction is CO_2_{(g)} and water vapour

Now from the reaction

    2 moles of C_8 H_{18}  will react with 25 moles of O_2 to give (16 + 18) moles of CO_2_{(g)} and  H_2 O_{(g)}

So

    1 mole of C_8 H_{18} will  react with 12.5 moles of  O_2 to give 17 moles of CO_2_{(g)} and  H_2 O_{(g)}

This implies that

    0.8754 moles of C_8 H_{18} will react with (12.5 * 0.8754 ) moles of O_2 to give  (17 * 0.8754) of CO_2_{(g)} and  H_2 O_{(g)}

So the no of moles of gaseous product is

         N_g = 17 * 0.8754

         N_g = 14.88 \ moles

From the ideal gas law

       PV = N_gRT

making V the subject

        V = \frac{N_gRT}{P}

Where R is the gas constant with a value R = 0.08206 \  L\cdot atm /K \cdot mole

Substituting values

          V = \frac{14.88* 0.08206 *623}{0.967}

          V = 787L

Part B

From the reaction the number of moles of oxygen that reacted is

         N_o = 0.8754 * 12.5

         N_o = 10.94 \ moles

The volume is

      V_o  = \frac{10.94 * 0.08206 *623}{0.967}

      V_o  = 579 \ L

No this volume is the 21% oxygen that reacted the 79% of air that did not react are the engine gaseous exhaust and this can be mathematically evaluated as

         V_e = V_o * \frac{0.79}{0.21}

Substituting values

       V_e = 579 * \frac{0.79}{0.21}

       V_e = 2178 \ L

3 0
3 years ago
Which is NOT correct for when the silver and vanadium half-cells are connected via a salt bridge and a potentiometer
lidiya [134]

The question is incomplete, the complete question is

Which is NOT correct for when the silver and vanadium half-cells are connected via a salt bridge and a potentiometer? Ag^+ + 1 e^- rightarrow Ag Edegree = 0.7993 V V^2+ + 2e^- right arrow V E degree =-1.125 V Ag+ is reduced V is oxidized 1.924 V V2^+ is reduced Ag is oxidized I and II III, IV, and V I, II, and III III only IV and V

Answer:

only IV and V

Explanation:

If we look at the values of reduction potential for the two species, we will discover that vanadium has a negative reduction potential indicating its tendency towards oxidation.

On the other hand, solve has a positive reduction potential indicating a tendency towards reduction.

This implies that vanadium must be oxidized and silver reduced and not the not her way ground? Hence the answer above.

7 0
3 years ago
Calculate the maximum wavelength of light that will cause the photoelectric
Drupady [299]

Answer:

Explanation:

Work function of potassium = 2.29 eV = 3.67 X 10⁻¹⁹ J

So the minimum energy of photon must be equal to 3.67 X 10⁻¹⁹ J .

energy of photon of wavelength λ = hc / λ

where h = 6.67  x 10⁻³⁴

c = 3 x 10⁸

Putting the values in the equation above

6.67  x 10⁻³⁴  x  3 x 10⁸ / λ =  3.67 X 10⁻¹⁹

λ  = 6.67  x 10⁻³⁴  x  3 x 10⁸ /  3.67 X 10⁻¹⁹

= 5.452 x 10⁻⁷

= 5452 x 10⁻¹⁰ m

= 5452 A .

6 0
4 years ago
calculate the mass required to prepare 2.5 L of 1.0 M NaOH solution. Given that the molar mass for NaOH is 40 g/mol.
Helen [10]

Answer:

The required mass to prepare 2.5 L of 1.0 M NaOH solution is 100 g

Explanation:

We do this by preparing the equation:

Mass = concentration (mol/L) x volume (L) x Molar mass

Mass = 1.0 M x 2.5 L x 40 g/mol

Mass = 100 g

3 0
3 years ago
Read 2 more answers
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