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2 years ago

Which of these describes a Mole in Chemistry?

Chemistry

1 answer:

olya-2409 [2.1K]2 years ago

5 0

Answer: Thus the correct option is D. All of the above describe a mole

Explanation:

According to avogadro's law, 1 mole of every substance weighs equal to molecular mass in grams.

1 mole of every substance contains avogadro's number $6.023\times 10^{23}$ of particles.

Mole is the S.I unit for measuring the amount of substance. It is often used to measure large number of particles.

Thus the correct option is D. All of the above describe a mole

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one reaction that produces hydrogen gas can be represented by the unbalanced chemical equation Mg(s)+HCI(aq) -> MgCI(aq)+H2(g

Sonbull [250]

<h3>Answer:</h3>

128 g HCl

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

<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>

Reading a Periodic Table

<u>Stoichiometry</u>

Reaction Mole Ratios
Using Dimensional Analysis

<h3>Explanation:</h3>

<u>Step 1: Define</u>

[RxN - Unbalanced] Mg (s) + HCl (aq) → MgCl (aq) + H₂ (g)

↓

[RxN - Balanced] 2Mg (s) + 2HCl (aq) → 2MgCl (aq) + H₂ (g)

[Given] 3.25 mol Mg

[Solve] x g HCl

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

[RxN] 2 mol Mg → 2 mol HCl

[PT] Molar Mass of H - 1.01 g/mol

[PT] Molar Mass of Cl - 35.45 g/mol

Molar Mass of HCl - 1.01 + 35.45 = 36.46 g/mol

<u>Step 3: Stoich</u>

[S - DA] Set up: $\displaystyle 3.25 \ mol \ Mg(\frac{2 \ mol \ HCl}{2 \ mol \ Mg})(\frac{36.46 \ g \ HCl}{1 \ mol \ HCl})$
[S - DA] Multiply/Divide [Cancel out units]: $\displaystyle 127.61 \ g \ HCl$

<u>Step 4: Check</u>

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

127.61 g HCl ≈ 128 g HCl

3 0

2 years ago

Aluminum has a density of 2.70 g/mL. Calculate the mass (in grams) of a piece of aluminum having a volume of 264 mL .

gavmur [86]

The formula for density is:

D = m/v

We can use the formula to figure out the mass because we already know two of the three values (we are given the density and volume), so we only have to solve for <em>m. </em>If we plug our given values into the formula, we get:

2.70 = m / 264

Now, all we need to do is solve for <em>m</em>. The goal is to get <em>m</em> on one side of the equation, and all we have to do is multiply each side of the equation by 264:

264 × 2.70 = (m÷264) × 264

264 × 2.70 = m

m = 712.8

The mass of the piece of aluminum is 712.8 grams.

4 0

3 years ago

Ultraviolet radiation and radiation of shorter wavelengths can damage biological molecules because they carry enough energy to b

Lelechka [254]

Answer:

343.98 nm is the longest wavelength of radiation with enough energy to break carbon–carbon bonds.

Explanation:

A typical carbon–carbon bond requires 348 kJ/mol=348000 J/mol

Energy required to breakl sigle C-C bond:E

$E=\frac{348000 J/mol}{6.022\times 10^{23} mol^{-1}}=5.7788\times 10^{-19} J$