rerouting a river the the correct option
Answer: 1.25 grams of Potassium-40
Explanation: When the amount of a compound is consumed by half, the time passed is called "the half life". This term is particularly important in nuclear chemistry. Potassium-40 is an isotope of potassium element and it is radioactive. As a result, the consumption time of this radioactive isotope is valuable information since radioactive isotopes are detrimental to health and nature.
For example, in this question, within 1.3 billion years, half amount of the potassium-40 disappears. 2.6 billion years ago, there were 5 grams of potassium-40 and when 1.3 billion years pass, half of the 5 grams of potassium-40 will disappear and there will will be 2.5 grams of potassium-40 left (5 grams of potassium-5 grams of potassium*(1/2)[half amount]=2.5 grams of potassium-40 left). As a result, 2.5 grams of potassium-40 is the amount that is present 1.3 billion years ago (2.6 billion years-1.3 billion years [half-life]=1.3 billion years). There will be 1.3 billion years left until today, so we still have to calculate the amount disappeared in 1.3 billion years. Thus, half of the 2.5 grams must disappear in 1.3 billion years left (2.5 grams - 2.5 grams*(1/2)[half amount]=1.25 grams). Finally, we have 1.25 grams of potassium-40 left since 2.6 billion years ago.
862^-10 my friend this is the answer
The equations of reaction occurring in the tubes are as follows:
- 2 MnO₄⁻ + 6 Br⁻ + 8 H⁺ → 2 MnO₂ + 3 Br₂ + 4 H₂O
- 2 MnO₄⁻ + 6 I⁻ + 8 H⁺ → 2 MnO₂ + 3 I₂ + 4 H₂O
- No reaction
- 2 Fe³⁺ + 2 I⁻ → 2 Fe²⁺ + I₂
<h3>What are the reactions occurring in the tubes?</h3>
The reactions occurring in the tubes are redox reactions.
Based on the table the equations of reaction are as follows:
- 2 MnO₄⁻ + 6 Br⁻ + 8 H⁺ → 2 MnO₂ + 3 Br₂ + 4 H₂O
- 2 MnO₄⁻ + 6 I⁻ + 8 H⁺ → 2 MnO₂ + 3 I₂ + 4 H₂O
- No reaction
- 2 Fe³⁺ + 2 I⁻ → 2 Fe²⁺ + I₂
In conclusion, redox reaction are reactions in which electrons are transferred.
Learn more about redox reactions at: brainly.com/question/26750732
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Answer:
2.1 × 10⁻¹ M
2.0 × 10⁻¹ m
Explanation:
Molarity
The molar mass of aniline (solute) is 93.13 g/mol. The moles corresponding to 3.9 g are:
3.9 g × (1 mol/93.13 g) = 0.042 mol
The volume of the solution is 200 mL (0.200 L). The molarity of aniline is:
M = 0.042 mol/0.200 L = 0.21 M = 2.1 × 10⁻¹ M
Molality
The moles of solute are 0.042 mol.
The density of the solvent is 1.05 g/mL. The mass corresponding to 200 mL is:
200 mL × 1.05 g/mL = 210 g = 0.210 kg
The molality of aniline is:
m = 0.042 mol/0.210 kg = 0.20 m = 2.0 × 10⁻¹ m
