Answer:
OPTION (A) : Testing a rock sample for gold content
Explanation:
For testing a rock sample of gold content you will need a Chemist. To test the material, the sample is rubbed on black stone which will leave a mark on the stone. This mark is tested by applying aqua fortis i.e nitric acid on the mark. If the mark gets dissolve then the material is not gold. If the mark sustain the it is further tested by applying aqua regia i.e nitric acid and hydrochloric acid which will prove the sample is of gold if it gets dissolve on using hydrochloric acid. The purity of the sample can be checked by differing the concentration of the aqua regia and comparing it with the gold material of the known purity.
Based on factors affecting solution formation;
- Strong solvent-solute intermolecular forces favors solution formation.
- Increase in entropy favours solution formation
- Decrease in enthalpy favours solution formation
<h3>What is a solution?</h3>
A solution is a substance formed when a substance known as solute dissolves in another substance know as solvent.
Factors that affect solution formation include:
- strength of intermolecular forces between solute and solvent
- entropy
- enthalpy
Strong solvent-solute intermolecular forces favors solution formation.
Increase in entropy favours solution formation
Decrease in enthalpy favours solution formation.
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Answer:
Static Friction.
Explanation:
Friction is the force that resists the relative motion between the surfaces sliding against each other.
Static friction is friction between objects that are not in relative motion with each other.
The coefficient of static friction, typically denoted as μs,
Static friction arises due to surface roughness( relative term)
The static friction force can be overcome by an applied maximum force
F max = μs x N
N= normal force
Any force smaller than F max attempting to slide one surface over the other is opposed by a frictional force of equal magnitude and opposite direction.
Any force larger than F max overcomes the force of static friction and causes sliding to occur.
This maximum force is sometimes called the limiting value also. Here that value is 75 N.
<span>C) The bonds prevent ions from moving throughout the crystal, so a solid ionic compound is a poor conductor is your answer, however, technically speaking the bonds prevent electrons from moving, since the ions are locked in place and don't want their electrons to go.</span>