Answer:
it is 55.84
Explanation:
it's 55.84 because that is the relative atomic mass of iron and iron is the formula for iron wool
Boiling point: the boiling point of compounds are all different. once a compound in a mixture reaches its boiling point, it will evaporate leaving behind the other compound that is yet to reach its boiling point.
if alcohol and water are mixed together, alcohol will boil first leaving behind water, hence water and alcohol have been separated
Answer:
The autoionization of water is:
2H₂O ⇄ H₃O⁺ + OH⁻ Kw
Explanation
2 moles of water can generate hydronium and hydroxide, when they work as an acid or as a base
If we take account that the concentration of protons (hydroniums), at the standard temperature is 1×10⁻⁷ M, it can be considered that the molarity of water is a constant that can be incorporated into a “greater” constant that also includes to Kc and that is known as ionic product of water, Kw. The expression is:
Kw = [H₃O⁺] . [OH⁻] / [H₂O]²
We do not include water → Kw = [H₃O⁺] . [OH⁻]
Since the water dissociation reaction produces the same concentration of H₃O⁺ as OH⁻, [OH⁻] in pure water will also be 1×10⁻⁷ M
Kw = 1×10⁻⁷ . 1×10⁻⁷ = 1×10⁻¹⁴
pKw = pH + pOH
14 = 7 + 7
Answer:
A. To be precise, it must be able to make measurements repeatedly over a long period of time.
Explanation:
The precision of a scientific measuring tool can be defined as how close the values between multiple measurements are to each other, when repeated under the same conditions.
This ultimately implies that, the precision of a scientific measuring tool reflects the reproducibility and repeatability of its measurements, irrespective of how accurate the measurements are.
In science, one of the most effective ways to determine the precision of a scientific measuring tool is to find the difference between the highest and lowest measurements (measured values).
Hence, the statement which correctly describes a characteristic that a scientific measuring tool should have is that, to be precise, it must be able to make measurements repeatedly over a long period of time.
