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2 years ago

How many atoms are present in 2.1 moles of Fe

Chemistry

1 answer:

Lyrx [107]2 years ago

4 0

Answer:

1.3 x 10²⁴ atoms Fe

Explanation:

To convert moles to atoms, you need to multiply your given value by Avogadro's Number. This causes the conversion to occur because Avogadro's Number exists as a ratio. It is the ratio that allows for the cancellation of units during multiplication. This is why atoms should be in the numerator of your conversion. The final answer should have 2 sig figs to reflect the given value.

Avogadro's Number:

1 mole = 6.022 x 10²³ atoms

2.1 moles Fe 6.022 x 10²³ atoms
--------------------- x ------------------------------- = 1.3 x 10²⁴ atoms Fe
1 mole

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How many moles in 4.93 x 10E23 atoms of silver?

leva [86]

<h3>Answer:</h3>

0.819 mol Ag

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right<u> </u>

<u>Chemistry</u>

<u>Atomic Structure</u>

Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

<u>Stoichiometry</u>

Using Dimensional Analysis

<h3>Explanation:</h3>

<u>Step 1: Define</u>

4.93 × 10²³ atoms Ag

<u>Step 2: Identify Conversions</u>

Avogadro's Number

<u>Step 3: Convert</u>

Set up: $\displaystyle 4.93 \cdot 10^{23} \ atoms \ Ag(\frac{1 \ mol \ Ag}{6.022 \cdot 10^{23} \ atoms \ Ag})$
Divide: $\displaystyle 0.818665 \ mol \ Ag$

<u>Step 4: Check</u>

<em>Follow sig fig rules and round. We are given 3 sig figs.</em>

0.818665 mol Ag ≈ 0.819 mol Ag

8 0

3 years ago

"How much NH4Cl, when present in 2.00 liters of 0.200 M ammonia, will give a solution with pH = 8.20? For NH3, Kb = 1.8 x 10-5"

Andru [333]

Answer:

245.66g of NH₄Cl is the mass we need to add to obtain the desire pH

Explanation:

The mixture of NH3/NH4Cl produce a buffer. We can find the pH of a buffer using H-H equation:

pH = pKa + log [A⁻] / [HA]

<em>Where [A⁻] is the molar concentration of the base, NH₃, and [HA] molar concentration of the acid, NH₄⁺. This molar concentration can be taken as the moles of each chemical</em>

<em />

First, we need to find pKa of NH₃ using Kb. Then, the moles of NH₃ and finally replace these values in H-H equation to solve moles of NH₄Cl we need to obtain the desire pH.

<em>pKa NH₃/NH₄⁺</em>

pKb = - log Kb

pKb = -log 1.8x10⁻⁵ = <em>4.74</em>

pKa = 14 - pKb

pKa = 14 - 4.74

pKa = 9.26

<em>Moles NH₃</em>

<em>2.00L ₓ (0.200mol NH₃ / L) = 0.400 moles NH₃</em>

<em>H-H equation:</em>

pH = pKa + log [NH₃] / [NH₄Cl]

8.20 = 9.26 + log [0.400 moles] / [NH₄Cl]

-1.06 = log [0.400 moles] / [NH₄Cl]

0.0087 = [0.400 moles] / [NH₄Cl]

[NH₄Cl] = 0.400 moles / 0.0087

[NH₄Cl] = 4.59 moles of NH₄Cl we need to add to original solution to obtain a pH of 8.20. In grams (Using molar mass NH₄Cl=53.491g/mol):

4.59 moles NH₄Cl ₓ (53.491g / mol) =

<h3>245.66g of NH₄Cl is the mass we need to add to obtain the desire pH</h3>

<em />

3 0

3 years ago

POINTS AND BRAINIEST ANSWER!!!!

denis23 [38]

Answer:

hydrgen = i think it is 4

oxygen = i think it is 3

Explanation:

3 0

3 years ago

Read 2 more answers

Which of the following is the best example of chemical weathering?

shepuryov [24]

Answer: A. Limestone rocks dissolving in water

Explanation:

B: This is a physical change; it changes an object physically rather than chemically. It does not change the composition of the concrete, only the shape.

C: This is also a physical change because the water is just dragging sand with it, but not actually changing the composition of it.

D: Similar to option B, this is an example of physical weathering because the ice only divides the rock into different parts but doesn't change the composition or complexity of it.

4 0

3 years ago

Which elements are found in ammonium hydroxide? NH4OH

Step2247 [10]

Ammonium hydroxide aka ammonia is a colorless gas that smells awful.... ammonia contains nitrogen and hydrogen.... and also ammonia is used as a lifting gas, which means it cans be used to lift hot air balloons.... lol that was just a weird fact..... but have an amazing day/night and god bless u!

3 0

3 years ago