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
How many electrons should Nitrogen (N) have around its Lewis dot model?
Delvig [45]

Answer:

5

Explanation:

3 0
3 years ago
Hydrogenation reactions, in which H2 and an "unsaturated" organic compound combine, are used in the food, fuel, and polymer indu
ddd [48]

<u>Answer:</u> The amount of heat released is 56 MJ.

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}  

Given mass of C_2H_6 = 12 kg = 12000 g    (Conversion factor: 1 kg = 1000 g)

Molar mass of C_2H_6 = 30 g/mol

Putting values in above equation, we get:

\text{Moles of }C_2H_6=\frac{12000g}{30g/mol}=400mol

The chemical reaction for hydrogenation of ethene follows the equation:

C_2H_4+H_2\rightarrow C_2H_6

By Stoichiometry of the reaction:

When 1 mole of ethane releases 140 kJ of heat.

So, 400 moles of ethane will release = \frac{140}{1}\times 400=56000kJ of heat.

Converting this into Mega joules, using the conversion factor:

1 MJ = 1000 kJ

So, \Rightarrow 56000kJ\times (\frac{1MJ}{1000kJ})=56MJ

Hence, the amount of heat released is 56 MJ.

8 0
3 years ago
Where do properties of matter come from?
Korolek [52]

Answer:

Extensive or inextinsive and either physical or chemical

8 0
2 years ago
When chemicals react with each other which factors decide that a successful reaction has taken place ?
Elodia [21]

The factors that affect the rate of a reaction are:

  • <em>nature of the reactant</em> - when reactants with different chemical composition are exposed to same conditions they would react differently.  For instance, when an acid or base is added on litmus paper, blue litmus paper turns red in presence of acid while red litmus paper turns blue when base is added.
  • <em>surface area</em>- a compound with small pieces spread over a large area will react faster than a big lump of a compound occupying a small area.
  • <em>temperature of reaction</em>- reactants would react faster at high temperatures. this is because they have higher kinetic energy to collide with each other. Hence a plate of food on the table spoils faster than a plate of food in the fridge.
  • <em>concentration</em>- an increase in concentration leads to more molecules available to collide and form products. An example, when you add more of indicator in a solution, the color becomes more clear since more particles react to give more color.
  • <em>presence of a catalyst</em>- a catalyst lowers the activation energy, which means less energy is required to shift reaction in forward direction. In the presence of iron (Fe) a catalyst, nitrogen N₂ and hydrogen H₂ react to produce NH₃
3 0
4 years ago
True or False? Unbalanced forces cause a change in motion <br> T/F <br><br> How do you know this?
Oxana [17]

Answer:

true

Explanation

Unbalanced forces can cause an object to change its motion.If an object is at rest and an unbalanced force pushes or pulls the object it will move. Unbalanced forces can also change the speed or direction of an object that is already in motion.

5 0
3 years ago
Read 2 more answers
Other questions:
  • Dalton hypothesized that atoms are indivisible and that all atoms of an element are identical. It is now known that _____.
    7·2 answers
  • Argon, which comprises almost 1 percent of the atmosphere, is approximately 27 times more abundant than CO2, but does not contri
    11·1 answer
  • Identify the missing nuclide in the following nuclear equation:
    5·1 answer
  • Write a word equation and a balanced symbol equation for the<br> combustion of hydrogen.
    15·1 answer
  • How many moles of hydrogen molecules (h2) would be required to produce two moles of hydrogen peroxide (h2o2)?
    12·1 answer
  • Three resonance structures of the given anion are possible. One is given, but it is incomplete. Complete the given structure by
    13·1 answer
  • What is the [H ] of a solution of 0.001 M aqueous sulfuric acid (H2SO4) is H2SO4 ionizes in water according to the balanced chem
    12·1 answer
  • Please help!
    15·1 answer
  • 75As3- what is it’s protons, neutrons, and electrons?
    14·1 answer
  • 4. A 14.5-L balloon is in the air where it is 20.0 C at 0.980-atm. A wind passes over and the balloon's pressure becomes 740.0-m
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!