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Korvikt [17]
4 years ago
5

An unknown is discovered to have three isotopes. 25% have a mass of 86.0, 66% have a

Chemistry
1 answer:
7nadin3 [17]4 years ago
7 0
It’s obvious that it’s 13 because 89 - 92 =13
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This gas is found in the stratosphere where it helps protect us from UV radiation.
Luba_88 [7]

Answer: A

Explanation:

3 0
3 years ago
Number of electrons present in 3.6mg of NH₄⁺?​
nata0808 [166]
0.0036g of NH4+ x 1mol of NH4+/18.04g of NH4+ x 6.02*10^23 electrons of NH4+/1mol of NH4+

= 1.20 x 10^20 electrons of NH4+
4 0
3 years ago
A sample of CO2 weighing 86.34g contains how many molecules?
irakobra [83]

Answer:

1.181 × 10²⁴ molecules CO₂

General Formulas and Concepts:

<u>Chemistry - Atomic Structure</u>

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

Explanation:

<u>Step 1: Define</u>

86.34 g CO₂

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

Avogadro's Number

Molar Mass of C - 12.01 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of CO₂ - 12.01 + 2(16.00) = 44.01 g/mol

<u>Step 3: Convert</u>

<u />86.34 \ g \ CO_2(\frac{1 \ mol \ CO_2}{44.01 \ g \ CO_2} )(\frac{6.022 \cdot 10^{23} \ molecules \ CO_2}{1 \ mol \ CO_2} ) = 1.18141 × 10²⁴ molecules CO₂

<u>Step 4: Check</u>

<em>We are given 4 sig figs. Follow sig fig rules and round.</em>

1.18141 × 10²⁴ molecules CO₂ ≈ 1.181 × 10²⁴ molecules CO₂

4 0
3 years ago
a 0.555 g sample of mayonnase was burned in excess oxygen inside a bomb calorimeter with a total heat capacity (bomb and water)
Fofino [41]

Answer:

Dietary\ Calories=65.6kcal

Explanation:

Hello!

In this case, since we can see that the heat released by the combustion of the mayonnaise is absorbed by the bomb calorimeter and water, we can set up the following equation:

m_{mayonnaise}q_{mayonnaise}=C\Delta T

Whereas q for mayonnaise stands for the heat due to its usage; thus, we plug in to obtain:

q_{mayonnaise}=\frac{5.20kJ/\°C*2.93\°C}{0.555g} \\\\q_{mayonnaise}=27.45\frac{kJ}{g}

Now, if 10.0 g are eaten, the energy provided by it turns out:

E_{mayonnaise}=27.45kJ/g*10.0g\\\\E_{mayonnaise}=274.5kJ

And we need that value in dietary calories, 1 kcal:

Dietary\ Calories=274.52kJ*\frac{1kcal}{4.184kJ}\\\\ Dietary\ Calories=65.6kcal

Best regards!

4 0
3 years ago
How many moles are present in 54.8 mL of mercury if the density of mercury is 13.6 g/mL?​
lesya692 [45]

Answer:

3.72 mol Hg

General Formulas and Concepts:

<u>Chemistry - Atomic Structure</u>

  • Reading a Periodic Table
  • Using Dimensional Analysis
  • Density = Mass over Volume

Explanation:

<u>Step 1: Define</u>

D = 13.6 g/mL

54.8 mL Hg

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

Molar Mass of Hg - 200.59 g/mol

<u>Step 3: Find</u>

13.6 g/mL = x g / 54.8 mL

x = 745.28 g Hg

<u>Step 4: Convert</u>

<u />745.28 \ g \ Hg(\frac{1 \ mol \ Hg}{200.59 \ g \ Hg} ) = 3.71544 mol Hg

<u>Step 5: Check</u>

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

3.71544 mol Hg ≈ 3.72 mol Hg

8 0
3 years ago
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