A) because when gas is produced it changes chemical form whereas the chemical change is obvious.
Answer:
6.82g
0.59moles
Explanation:
1. What is the mass sample of 0.0500 moles of zinc chloride ?
Given parameters:
Number of moles ZnCl₂ = 0.05moles
Unknown:
Mass of the sample = ?
Solution:
To find the mass of a substance using the number of moles, it would be pertinent to understand what mole is.
A mole is a substance that contains the avogadro's number of particles.
It relates to the mass using the expression below;
Mass of a substance = number of moles x molar mass
Molar mass of ZnCl₂;
Atomic mass of Zn = 65.4g/mol
Cl = 35.5g/mol
Molar mass = 65.4 + 2(35.5) = 136.4g/mole
Mass of a substance = 0.05 x 136.4 = 6.82g
2. How many moles of potassium sulfide are in a 65.50g sample?
Given parameters:
Mass of K₂S = 65.5g
Unknown:
Number of moles = ?
Solution:
The number of moles of any substance is related to mass using the expression below;
Number of moles = 
Molar mass of K₂S = 2(39) + 32 = 110g/mol
Number of moles =
= 0.59moles
When investigative officers get to a crime scene, they do not need to collect water samples.
<h3>What is a crime scene?</h3>
A crime scene is a place where an offence has been committed. It is usually cordoned off to enable investigation of the crime and the collection of samples.
When investigative officers get to a crime scene, they do not need to collect water samples.
Learn more about investigation:brainly.com/question/1191670
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<span>Chemical reaction: CH</span>₃COO⁻(aq) + H⁺(aq) ⇄ CH₃COOH(aq).
H⁺ is from HNO₃: HNO₃ → H⁺ + NO₃⁻.
<span>A buffer can
be defined as a substance that prevents the pH of a solution from changing by
either releasing or absorbing H</span>⁺ in a
solution.
Buffer is a solution
that can resist pH change upon the addition of an acidic or basic components
and it is able to neutralize small amounts of added acid or base, pH of
the solution is relatively stable.