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Citrus2011 [14]
3 years ago
12

Copper has two isotopes,

Chemistry
1 answer:
Anestetic [448]3 years ago
5 0

Answer:

69.152 % → 63Cu

30.848 % → 65Cu

Explanation:

As you know, the average atomic mass of an element is determined by taking the weighted average of the atomic masses of its naturally occurring isotopes.

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Why do we need to calibrate equipment​
Vlad1618 [11]

Answer:

to be precise in the calculations

Explanation: for example your cell phone has a gps inside it, the gps is responsible for providing direction data like a compass, if the equipment is not calibrated, the gps will not find the correct direction.

3 0
3 years ago
Determine the number of moles of gas contained in a 1.25 L container at 25 degrees Celsius and 800 torr
tiny-mole [99]
You would have to use the ideal gas law: PV = nRT where,

P = pressure
V = volume
n = moles
R = universal gas constant for a specific pressure (in this case it's 62.364 torr)
T = temperature in Kelvin

First, convert Celsius to kelvin by adding 273 to 25, which gives you 298K

Now plug in your variables to find n:

(800 torr)(1.25 L) = n(62.364)(298K)

1000 = 18584.472n

Now divide 1000 by 18584.472 to get n:

1000/18584.472 = 0.054 moles
8 0
3 years ago
Which statement about the elements in the periodic table is true
egoroff_w [7]

A. The number of valence electrons increases as atomic mass increases. == Generally true for the representative elements since atomic mass generally increases with increasing Z.  

B. The reactivity of alkali metals increases as atomic mass increases. == True. Atomic mass increases down the column and so does reactivity  

C. The reactivity of the halogens increases as atomic mass increases. == False. Reactivity decreases down the column.  

D. The number of valence electrons decreases across a period. == False. In general, the number of valence electrons increases across a period, particularly for the representative elements.

6 0
3 years ago
Read 2 more answers
What is the vocab word for are first to grow in a new or disturbed area
ehidna [41]
Not quite sure what you're asking, but I think what you're looking for is 'Native Species'.
5 0
4 years ago
How much heat, in joules and in calories, must be added to a 75.0–g iron block with a specific heat of 0.449 j/g °c to increas
lianna [129]

Answer:

Q=50,849.25J\\\\Q=12,153.3cal

Explanation:

Hello!

In this case, given the mass, temperature change and specific heat, it is possible to compute the required heat in joules as shown below:

Q=mC(T_2-T_1)\\\\Q=75.0g*0.449\frac{J}{g\°C}(1535\°C-25\°C)\\\\Q=50,849.25J

Now, since 1 cal =4.184 J, this result in calories is:

Q=50,849.25J*\frac{1cal}{4.184J}\\\\Q=12,153.3cal

Best regards!

7 0
3 years ago
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