1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Karo-lina-s [1.5K]
3 years ago
7

Many metals pack in cubic unit cells. The density of a metal and length of the unit cell can be used to determine the type for p

acking. For example, polonium has a density of 9.19 g/cm3 and a unit cell side length a of 3.37 Å. (1 Å = 1 10-8 cm.) (a) How many polonium atoms are in exactly 1 cm3? atoms (b) How many unit cells are in exactly 1 cm3? unit cells (c) How many polonium atoms are there per unit cell?
Chemistry
1 answer:
jarptica [38.1K]3 years ago
3 0

Answer:

A.) 34.866 x 10¯23 g/atom

B.) 2.64 x 10^22 atoms in 1 cm3

C.) 1 atoms per unit cell

Explanation:

A) Calculate the average mass of one atom of polonium:

210g mol¯1 ÷ 6.022 x 1023 atoms mol¯1 = 34.866 x 10¯23 g/atom

B) Determine atoms in 1 cm3:

9.19g / 34.866x 10¯23 g/atom = 2.64 x 10^22 atoms in 1 cm3

Determine volume of the unit cell:

(3.37 x 10¯8 cm)3 = 3.827 x 10¯23 cm3

Determine number of unit cells in 1 cm3:

1 cm3 / 3.827 x 10¯23 cm3 = 2.61 x 1022 unit cells

C) Determine atoms per unit cell:

2.64 x 1022 atoms / 2.61 x 1022 unit cells = 1 atoms per unit cell

You might be interested in
Consider the following standard heats of formation:
cluponka [151]

Answer:

<u>The Standard enthalpy of reaction:</u> \Delta H_{r}^{\circ } = -290\,kJ            

Explanation:

Given- Standard Heat of Formation:

\Delta H_{f}^{\circ } [P_{4}O_{10}(s)] = -3110 kJ/mol,

\Delta H_{f}^{\circ } [H_{2}O(l)] = -286 kJ/mol,

\Delta H_{f}^{\circ } [H_{3}PO_{4}(s)] = -1279 kJ/mol

<u><em>Given chemical reaction:</em></u> P₄O₁₀(s) + 6H₂O → 4H₃PO₄

<em>The standard enthalpy of reaction:</em> \Delta H_{r}^{\circ } = ?

<u><em>To calculate the Standard enthalpy of reaction</em></u> (\Delta H_{r}^{\circ }), <u><em>we use the equation:</em></u>

\Delta H_{r}^{\circ } = \sum \nu .\Delta H_{f}^{\circ }(products)-\sum \nu .\Delta H_{f}^{\circ }(reactants)

\Delta H_{r}^{\circ } = [4 \times \Delta H_{f}^{\circ } [H_{3}PO_{4}(s)]] - [1 \times \Delta H_{f}^{\circ } [P_{4}O_{10}(s)] + 6 \times \Delta H_{f}^{\circ } [H_{2}O(l)]]

\Rightarrow \Delta H_{r}^{\circ } = [4 \times (-1279\, kJ/mol)] - [1 \times (-3110\, kJ/mol) + 6 \times (-286\, kJ/mol)]

\Rightarrow \Delta H_{r}^{\circ } = [-5116\, kJ] - [-3110\, kJ -1716\, kJ]

\Rightarrow \Delta H_{r}^{\circ } = [-5116\, kJ] - [-4826\, kJ] = -290\,kJ

<u>Therefore, the Standard enthalpy of reaction:</u> \Delta H_{r}^{\circ } = -290\,kJ

3 0
3 years ago
Which of the following is composed of organic compounds?
OLEGan [10]
The best answer would be HUMANS.

This is because organic compounds are essentially carbon based compounds and the human body is made up of many such compounds such as the protein that makes up skin, hair, nails, hormones and enzymes; gylcoproteins that are essential for cell membrane; fat found in skin and other tissues.
3 0
3 years ago
Read 2 more answers
Fish and reptiles share which of these traits?
Naddika [18.5K]
I think it might be a or b but I’m 97% sure the answers is b
8 0
2 years ago
A student wants to prepare 250.0 mL of 0.10 M NaCl solution. Which procedure is most appropriate? (formula Molar Mass of NaCl =
Anvisha [2.4K]

The correct answer is option B, that is, add 1.46 grams of NaCl to 250 milliliters of H₂O.

First there is a need to find the moles of NaCl in 250 ml of 0.10 M NaCl,

Moles of NaCl = molarity × volume = 0.10 M × (250/1000L) = 0.025 mol

The corresponding mass of NaCl is,

Mass of NaCl = moles × molar mass = 0.025 mol × 58.5 g/mol = 1.46 g

Thus, there is a need to dissolve 1.46 grams of NaCl solid into 50 ml of H₂O and dilute to 250 ml.

3 0
3 years ago
If sufficient acid is used to react completely
Juli2301 [7.4K]

Solution,

Mass of Mg - 21gm

molar mass of Mg - 24gm

moles = Given mass/ Molar mass

moles = 21/24 = 0.875

1 mole of Mg produce 1 mole of H2 gas

so 0.875 mole of Mg will produce 0.875 moles of H2 gas

One mole of H2 gas = 22.4 litre

0.875 mole of H2 gas = 0.875×22.4

0.875 mole of H2 gas = 19.60 litre

So the nearest ANSWER is Option four 19.37 litre.

3 0
2 years ago
Other questions:
  • In the image above, the girl is using her arm to lift a weight. Her arm is acting as a _______.
    6·1 answer
  • What is the solute in a solution
    10·2 answers
  • The prefix centi- means
    11·2 answers
  • After 15 minutes, 30 g of a sample of polonium-218 remain unchanged. If the original sample had a mass of 960 g, what is the hal
    11·1 answer
  • A single atom of calcium could combine with a single atom of fluorine, creating electron energy stability for both atoms. True F
    13·1 answer
  • A gas with a volume of 4.0L at a pressure of 205kPa is allowed to expand to a volume of 12.0L. What is the pressure in the conta
    11·1 answer
  • TOMMY (persistently but a little intimidated by the crowd) It's always that way, in every story I ever read about a ship landing
    9·1 answer
  • PLEASE HELP ME WITH THID IFK IT!! ILL GIVE YOU EXTRA POINTS
    7·1 answer
  • Compuesto organico que no existe como alqueno ni alquino?
    12·1 answer
  • When 2 moles of C6H6 react with excess Oxygen gas, how many moles of water are produced?
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!