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katrin [286]
3 years ago
13

How many atoms are in a sample of 68.7 grams copper (Cu)?

Chemistry
2 answers:
qwelly [4]3 years ago
8 0
First find the moles of the substance: Moles = mass / RFM 

moles = 68.7 / 
kondaur [170]3 years ago
7 0
To find the number of atoms in the sample of copper, we need its atomic mass and the use of the Avogadro's number to find the equivalent units in terms of atoms.

68.7 g Cu ( 1 mol / 63.55 g ) ( 6.022 x 10^23 atoms / 1 mol ) = 6.51 x 10^23 atoms Cu
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The energy of an electron in a multielectron atom is determined by
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Answer:

by principal quantum number (n) and azimuthal quantum number (l)

Explanation:

I used the web to answer so I'm not sure if this is right

5 0
3 years ago
The graph shows the solubility of several different salts in water, across a range of temperatures. According to the
sladkih [1.3K]

Answer:

  • <u><em>Sodium chloride</em></u>
  • See the graph attached

Explanation:

The attached graph with a green and a red arrow facilitates the understanding of this explanation.

To read the <em>solubility </em>on the <em>graph</em>, you can start with the temperature, on the x-axis.

The red vertical arrow shows how, departing from the <em>40ºC temperature</em> on the x-axis, you intersect the<em> solutibility curve </em>of sodium chloride at a height (y-axis) corresponding to <em>60 g/100cm³ of water</em> (follow the green horizontal arrow).

Hence, <em>sodium chloride is the salt that can dissolve at a concentration of about 60g/100cm³ of water at 40ºC.</em>

4 0
3 years ago
Read 2 more answers
One mole of carbon (12.0 g) in the form of crystalline graphite is burned at 25◦C and 1.000 atm pressure to form CO2(g). All of
iogann1982 [59]

Answer:

T₂ = 43.46 °C  

Explanation:

Given that:

The heat of the formation of carbon dioxide = - 393.5 kJ/mol (Negative sign suggests heat loss)

It means that energy released when 1 mole of carbon undergoes combustion = 393.5 kJ = 393500 J

Heat gain by water = Heat lost by the reaction

Thus,    

m_{water}\times C_{water}\times \Delta T=Q

For water:  

Mass of water  = 5100 g

Specific heat of water = 4.18 J/g°C  

T₁ = 25 °C  

T₂ = ?

Q = 393500 J

So,

5100\times 4.18\times (T_2-25)=393500  

T₂ = 43.46 °C  

6 0
3 years ago
Irradiated PVC insulated jacket can withstand a maximum temperature of?
horsena [70]
The maximum temperature that a PVC can withstand is 130° C. Beyond this the PVC will melt. From the choices given the correct answer is option D. 130° C.
4 0
3 years ago
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How many moles of I2 will form 3.58 g of NI3?
Mila [183]

1.       The balanced chemical reaction is:

 

N2 +3 I2 = 2NI3

 

We are given the amount of product formed. This will be the starting point of our calculations.

 

3.58 g NI3 ( 1 mol NI3 / 394.71 g NI3 ) ( 3 mol I2 / 2 mol NI3 ) = 0.014 mol I2.

 

Thus, 0.014 mol of I2 is needed to form the given amount of NI3.

6 0
3 years ago
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