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Korvikt [17]
3 years ago
7

How many moles of calcium atoms do you have if you have 3.00 × 10²¹ atoms of calcium. (The mass of one mole of calcium is 40.08

g.)
Chemistry
2 answers:
Talja [164]3 years ago
5 0

Answer:

0.0050moles

Explanation:

Since

1 mole=6.022×10^23

X mole=3.0×10^21

Cross multiply

6.022×10^23x=3.0×10^21

Divide both sides by 6.022×10^23

x=0.00498~0.0050moles

So the final answer is 0.0050moles

Nadya [2.5K]3 years ago
3 0

Answer:

4.98x10^-3 mole

Explanation:

According to Avogadro's hypothesis, 1 mole of any substance contains 6.02x10^23 atoms. This greatly implies that 1 mole of calcium will also contain 6.02x10^23 atoms.

Now, if 1 mole of calcium contains 6.02x10^23 atoms,

then Xmol of calcium will contain 3x10^21 atoms i.e

Xmol of calcium = 3x10^21/6.02x10^23

Xmol of calcium = 4.98x10^-3mol

Therefore, 4.98x10^-3 mole of calcium contains 3x10^21 atoms

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6.285×10^3 mg = _____? _____ kg
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One kilogram is equal to one thousand grams. Further, one gram is equal to 1000 mg. The conversion is as shown below,
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The numerical value of the operation above is 0.006285 kg. 
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What purpose does ammonia lauryl sulfate serve as a surfactor
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Answer:

See below  

Step-by-step explanation:

Ammonium lauryl sulfate has the structural formula CH₃CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂OSO₂O⁻ NH₄⁺.

The long nonpolar hydrocarbon chain and the ionic sulfate end group make it a surfactant.  

The ionic end tends to dissolve in water, but the nonpolar chain does not. This makes the compound an excellent <em>foaming agent,</em> so it is used in many shampoos and toothpastes.

The molecules form <em>micelles</em> in water, small spherical shapes with the polar heads outside, facing the water, and the nonpolar tails are inside.

They reduce the surface tension or the water so that, when you brush your teeth or shampoo your hair, the air bubbles are stable and do not break.

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4 years ago
Describe at least two methods to separate a mixture of small copper and iron beads
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3 0
3 years ago
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How many moles of Cu(OH)2 are soluble in 1L of sodium hydroxide (NaOH) when the pH is 8.23?
Morgarella [4.7K]

Answer:

4.96E-8 moles of Cu(OH)2

Explanation:

Kps es the constant referring to how much a substance can be dissolved in water. Using Kps, it is possible to know the concentration of weak electrolytes. Then, pKps is the minus logarithm of Kps.

Now, we know that sodium hydroxide (NaOH) is a strong electrolyte, who is completely dissolved in water. Therefore the pH depends only on OH concentration originating from NaOH. Let us to figure out how much is that OH concentration.

pH= -log[H]\\pH= -log (\frac{kw}{[OH]})

8.23 = - log(\frac{Kw}{[OH]} \\10^{-8.23} = Kw/[OH]\\ [OH] = Kw/10^{-8.23}

[OH]=1.69E-6

This concentration of OH affects the disociation of Cu(OH)2. Let us see the dissociation reaction:

Cu(OH)_2 -> Cu^{2+} + 2OH^-

In the equilibrum, exist a concentration of OH already, that we knew, and it will be added that from dissociation, called "s":

The expression for Kps is:

Kps= [Cu^{2+}] [OH]^2

The moles of (CuOH)2 soluble are limitated for the concentration of OH present, according to the next equation.

Kps= s*(2s+1.69E-6)^2

"s" is the soluble quantity of Cu(OH)2.

The solution for this third grade equation is s=4.96E-8 mol/L

Now, let us calculate the moles in 1 L:

moles Cu(OH)_2 = 4.96E-8 mol/L * 1 L = 4.96E-8 moles

7 0
4 years ago
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