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3 years ago

What is the mass of 1.20 x 10^25 atoms of He

Chemistry

1 answer:

AleksandrR [38]3 years ago

4 0

Answer:

79.7 g He

General Formulas and Concepts:

Chemistry - Atomic Structure

Reading a Periodic Table
Using Dimensional Analysis
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Explanation:

Step 1: Define

1.20 × 10²⁵ atoms He

Step 2: Identify Conversions

Avogadro's Number

Molar Mass of He - 4.00 g/mol

Step 3: Convert

$1.20 \cdot 10^{25} \ atoms \ He(\frac{1 \ mol \ He}{6.022 \cdot 10^{23} \ atoms \ He} )(\frac{4.00 \ g \ He}{1 \ mol \ He} )$ = 79.7077 g He

Step 4: Check

We are given 3 sig figs. Follow sig fig rules and round.

79.7077 g He ≈ 79.7 g He

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What is the hydrochloric acid concentration of a solution that has a pH of 2.9?

andre [41]

Answer:

0.00126M

Explanation:

First, we need to obtain the H+ concentration. This is illustrated below:

pH = 2.9

pH = —Log [H+]

2.9 = —log [H+]

— 2.9 = Log [H+]

Anti log of —2.9 ie

[H+] = 10^—2.9

[H+] = 0.00126M

Now let us generate the dissociation equation of HCl. This is illustrated below:

HCl <==> H+ + Cl-

From the ionic equation,

Since 1 mole of H+ is produced by 1mole of HCl, this implies that 0.00126M of H+ will also be produce by 0.00126M of HCl.

Therefore the molarity of HCl is 0.00126M

3 0

3 years ago

Which 5-carbon intermediate of the citric acid cycle is converted to a 4-carbon molecule with the release of carbon dioxide?

Pavlova-9 [17]

The alpha- ketoglutarate is the 5-carbon intermediate of the citric acid cycle which converted to a 4-carbon molecule with the release of carbon dioxide

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The alpha- ketoglutarate is the 5-carbon intermediate of the citric acid cycle which is salt of alpha ketoglutaric acid. The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle.

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8 0

2 years ago

How many moles is 1.50x10^23 molecules of NH3?

S_A_V [24]

The number of moles that are 1.50 x10^23 molecules of NH3 are

=0.249 moles

calculation

The number of moles is calculated using Avogadro's law constant

that is According to Avogadro's law

1 moles of a substance = 6.02 x10^23 molecules

? moles = 1.50 x10^23 molecules

by cross multiplication

= [( 1.50 x 10^23 molecules x 1 moles) / (6.02 x10^23)] = 0.249 moles

8 0

4 years ago

Read 2 more answers

PLEASE HELP WITH ALL! Do the following Mole conversions:

ExtremeBDS [4]

Answer:

The answer to your question is below

Explanation:

1) number of molecules = x

23 g of CoCl₂

Molar mass CoCl₂ = 59 + 71 = 130 g

130 g ------------------ 6.023 x 10²³ molecules

23 g ----------------- x

x = (23 x 6.023 x 10²³) / 130

x = 1.066 x 10²³ molecules

3.2 moles of H₃PO₄ to grams

Molar mass = 3 + 31 + (16 x 4)

= 98 g

98 g ------------------- 1 mol

x ------------------- 3.2 moles

x = (3.2 x 98)/1

x = 313.6 g

2.2 moles of (NH₄)₂ to grams

Molar mass = (14 x 2) + (8 x 1)

= 36 g

36 g of (NH₄)₂ ---------------- 1 mol

x ---------------- 2.2 moles

x = (2.2 x 36)/1

x = 79.2 grams

Molecules = ? 4.5 g of NH₄SO₂

Molar mass = 14 + 32 + 32 + 4

= 82 g

82 g of NH₄SO₂ --------------- 6.023 x 10²³ molecules

4.5 g ---------------- x

x = (4.5 x 6.023 x 10²³) / 82

x = 3.3 x 10²³ molecules

Liters of N₂ = ? 7.9 x 10³⁰ particles

22.4 l --------------------- 6.023 x 10²³ particles

x -------------------- 7.9 x 10³⁰

x = (7.9 x 10³⁰ x 22.4) / 6.023 x 10²³

x = 2.93 x 10⁸ particles

7 0

3 years ago

Calculate the unknown quantity in each of the following measurements of gases ?

hjlf

You have to google the answers

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4 years ago