All categories

3 years ago

7. Carbon-11 has a half-life of 20 minutes. Explain what this means.

Chemistry

1 answer:

Nikolay [14]3 years ago

6 0

Answer:

half life of carbon 11=20 mins

it means that after 20 mins the given sample of carbon-11 will reduce by half of its original value

Explanation:

You might be interested in

In Latin, the word arthropod means jointed foot.

lord [1]

Answer: a pair of antennae

Explanation:

6 0

2 years ago

How does the electron-cloud model describe electrons?

Sav [38]

Answer:

C. An electron has a high probability of being in certain regions.

Explanation:

In the electron cloud model, there are no electron-orbits around the nucleus but a cloud. This cloud has various densities with respect to distance from the nucleus. The most dense region of the cloud (which is the region close to the nucleus) is where electrons has the highest probability of existence.

The model explains that an electron a greater chance of being in the region closer to the nucleus. Thus, an electron has a high probability of being in certain region of the cloud about the central nucleus. And an electrostatic force exists between the nucleus and the electrons.

7 0

2 years ago

Hydroelectric power plants capture the ______________ of falling water to generate electricity. The falling water turns a wheel

LiRa [457]

Answer:

1: energy

2: converts

Kinetic energy is either 3 or 4, those questions are really similar.

3 0

2 years ago

As with other ionic compounds, potassium bromate, KBrO3, dissociates into ions when it dissolves in water. If 13.8 g of KBrO3 is

chubhunter [2.5K]

Answer:

ΔH of dissociation is 38,0 kJ/mol

Explanation:

The dissociation reaction of KBrO₃ is:

<em>KBrO₃ → K⁺ + BrO₃⁻ </em>

This dissolution consume heat that is evidenced with the decrease in water temperature.

The heat consumed is:

q = CΔTm

Where C is specific heat of water (4,186 J/mol°C)

ΔT is the temperature changing (18,0°C - 13,0°C = 5,0°C)

And m is mass of water (150,0 mL ≈ 150,0 g)

Replacing, heat consumed is:

q = 3139,5 J ≡ 3,14 kJ

13,8 g of KBrO₃ are:

13,8 g×(1mol/167g) = 0,0826 moles

Thus, ΔH of dissociation is:

3,14kJ / 0,0826mol = <em>38,0 kJ/mol</em>

I hope it helps!

3 0

2 years ago

How many moles of ethanol are produced starting with 500.g glucose?

Monica [59]

<h3>Answer:</h3>

5.55 mol C₂H₅OH

<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>

Reading a Periodic Tables
Moles

<u>Stoichiometry</u>

Using Dimensional Analysis
Analyzing Reactions RxN

<h3>Explanation:</h3>

<u>Step 1: Define</u>

[RxN - Balanced] C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂

[Given] 500. g C₆H₁₂O₆ (Glucose)

[Solve] moles C₂H₅OH (Ethanol)

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

[RxN] 1 mol C₆H₁₂O₆ → 2 mol C₂H₅OH

[PT] Molar mass of C - 12.01 g/mol

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

[PT] Molar Mass of O - 16.00 g/mol

Molar Mass of C₆H₁₂O₆ - 6(12.01) + 12(1.01) + 6(16.00) = 180.18 g/mol

<u>Step 3: Stoichiometry</u>

[DA] Set up conversion: $\displaystyle 500 \ g \ C_6H_{12}O_6(\frac{1 \ mol \ C_6H_{12}O_6}{180.18 \ g \ C_6H_{12}O_6})(\frac{2 \ mol \ C_2H_5OH}{1 \ mol \ C_6H_{12}O_6})$
[DA} Multiply/Divide [Cancel out units]: $\displaystyle 5.55001 \ mol \ C_2H_5OH$

<u>Step 4: Check</u>

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

5.55001 mol C₂H₅OH ≈ 5.55 mol C₂H₅OH

8 0

3 years ago