For the second one it is physical
Copper oxidizes in moist air
2Cu + CO₂ + O₂ + H₂O = (CuOH)₂CO₃
copper reacts with concentrated acids, for example, with nitric acid
Cu + 4HNO₃ = Cu(NO₃)₂ + 2NO₂ + 2H₂O
copper reacts with chlorine
Cu + Cl₂ = CuCl₂
copper reacts with oxygen when heated
2Cu + O₂ = 2CuO
Answer:
1 million years
Explanation:
The half life of a radioactive isotope refers to the time it takes for the radioactive isotope to decay to half of its original amount.
The half life of a radioactive isotope is independent of the amount of starting material. Hence, whether the amount of starting material is small or large, the half life of the substance remains the same.
Hence the half life of 2 green marbles and 500,000 green marbles is 1 million years.
Answer: 3.59
Explanation:
(2.06)(1.743)(1.00)
2.06 × 1.743 × 1.00
= 3.59058
Two of the multiplied digits are represented in 3 significant figures. Therefore, for correct representation, the result of the product should be written to three significant figures.
3.59058 to 3 significant figures:
First three digits = 3.59
Fourth digit '0' is less than 5, and thus rounded to 0 with other succeeding digits
Therefore, (2.06)(1.743)(1.00) to 3 significant figures equals :
3.59
Answer:
Kb = [CH₃NH₃⁺] × [OH⁻] / [CH₃NH₂]
Explanation:
According to Brönsted-Lowry acid-base theory:
- An acid is a substance that donates H⁺.
- A base is a substance that accepts H⁺.
When methylamine reacts with water, it behaves as a Brönsted-Lowry base, according to the following reaction.
CH₃NH₂(aq) + H₂O(l) ⇄ CH₃NH₃⁺(aq) + OH⁻(aq)
The basic equilibrium constant (Kb) is:
Kb = [CH₃NH₃⁺] × [OH⁻] / [CH₃NH₂]
