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ddd [48]
2 years ago
6

If a penny is made of 3.11 grams of copper, how many atoms of copper are in the penny

Chemistry
1 answer:
Pie2 years ago
8 0

Answer:

2.94x10²² atoms of Cu

Explanation:

We must work with NA to solve this, where NA is the number of Avogadro, number of particles of 1 mol of anything.

Molar mass Cu = 63.55 g/mol

Mass / Molar mass = Mol → 3.11 g / 63.55 g/m = 0.0489 moles

1 mol  of Cu has 6.02x10²³ atoms of Cu

0.0489 moles of Cu, will have (0.0489  .NA)/ 1 = 2.94x10²² atoms of Cu

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What is the element with the nlx notation of 5d2?
lesantik [10]
The element with the nlx notation of 5d2 in the periodic table is hafnium with a symbol of hf. It is a chemical element and has an atomic number 72. H<span>afnium chemically resembles zirconium and is found in many zirconium minerals but it is a complete contrast of zirconium which is also chemically similar to hafnium.</span>
7 0
2 years ago
A standard backpack is approximately 30cm x 30cm x 40cm. Suppose you find a hoard of pure gold while treasure hunting in the wil
Blizzard [7]

Explanation:

The dimensions of a standard backpack is 30cm x 30cm x 40cm

The mass of an average student is 70 kg

We know that, the density of gold is 19.3 g/cm³.

Let m be the mass of the backpack. So,

\text{density}=\dfrac{\text{mass}}{\text{volume}}\\\\m=d\times V\\\\m=19.3\ g/cm^3\times (30\times 30\times 40)\ cm^3\\\\m=694800\ g\\\\\text{or}\\\\m=694.8\ kg\approx 700\ kg

An average student has a mass of 70 kg. If we compare the mass of student and mass of backpack, we find that the backpack is 10 times of the mass of the student.

8 0
2 years ago
Find the age t of a sample, if the total mass of carbon in the sample is mc, the activity of the sample is a, the current ratio
kkurt [141]
should be 7.57*10^3 years
4 0
2 years ago
Which of the following statements is true about energy quantization at the atomic level? Electrons in the outermost orbits are t
MAVERICK [17]
<h2>Answer:</h2>

The correct answer is option C which is, "Electrons in the orbit closest to the nucleus have the least amount of energy".

<h3>Explanation:</h3>
  • There are different orbitals around the nucleus on which the electrons moves around the nucleus.
  • These orbitals have a specific energy, due to which they are known as energy levels.
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8 0
2 years ago
To determine the concentration of ethanol in cognac a 5.00 mL sample of the cognac is diluted to 0.500 L. Analysis of the dilute
julia-pushkina [17]

Answer : The molar concentration of ethanol in the undiluted cognac is 8.44 M

Explanation :

Using neutralization law,

M_1V_1=M_2V_2

where,

M_1 = molar concentration of undiluted cognac = ?

M_2 = molar concentration of diluted cognac = 0.0844 M

V_1 =  volume of undiluted cognac = 5.00 mL = 0.005 L

V_2 = volume of diluted cognac = 0.500 L

Now put all the given values in the above law, we get molar concentration of ethanol in the undiluted cognac.

M_1\times 0.005L=0.0844M\times 0.500L

M_1=8.44M

Therefore, the molar concentration of ethanol in the undiluted cognac is 8.44 M

4 0
2 years ago
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