Answer:
(a) Avoid parallax error
(b) To ensure that almost all the SCN⁻ has reacted.
Explanation:
(a) Avoiding bias
A Mohr pipet is a graduated pipet. To avoid bias, you should always hold the pipet so the meniscus is at eye level.
If your eye is above or below the meniscus, you will get an incorrect reading of the volume.
(b) Excess Fe³⁺
I am guessing that you are adding different volumes of SCN⁻ to Fe³⁺ to generate a Beer's Law plot of the concentration of FeSCN²⁺.
The problem is that the reaction is an equilibrium It does not go to completion.
Fe³⁺ + SCN⁻ ⇌ FeSCN²⁺
You use a large excess of Fe³⁺ to drive the position of equilibrium to the right and make sure that almost all the added SCN⁻ is converted to FeSCN²⁺.
The medium through which a wave travels depends on the type of wave. Mechanical waves require a physical substance for propagation, while electromagnetic waves can travel through both material mediums and empty space due to their unique field-based nature.
The medium through which a wave travels is the substance or material that carries the energy of the wave from one place to another. Waves can propagate through a variety of mediums, and the nature of the medium has a significant impact on the characteristics of the wave.
In mechanical waves, such as sound waves and seismic waves, the medium is typically a material like air, water, or solid objects. In the case of sound waves, air molecules vibrate as the wave passes through, transmitting compressions and rarefactions that our ears perceive as sound. In seismic waves, the Earth's crust and mantle serve as the medium, with rocks transmitting the wave energy.
Electromagnetic waves, like light and radio waves, do not require a physical medium to travel through. They can propagate through a vacuum, such as space, as well as through materials like air, water, and glass. This is because electromagnetic waves consist of oscillating electric and magnetic fields that can interact with charged particles in matter or propagate freely through the vacuum of space.
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Chemists and Physicists use controlled experiments and scientific tools like microscopes and spectrometers to study the chemical and physical properties of matter.
Scientists, particularly Chemists and Physicists, are the ones who use experiments and scientific tools to study matter. They conduct controlled experiments to investigate the physical and chemical properties of different types of matter. For instance, they utilize scientific tools such as microscopes, spectrometers, and calorimeters to measure, observe, and analyze matter at various levels. By using these tools, scientists are able to gather precise and reliable data to better understand the composition, structure, and reactions of matter.
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True or false?
Answer:
true
Explanation:
phosphorescent
radioactive
photosensitive
Answer & Explanation:
The difference between a physical reaction and a chemical reaction is composition. In a chemical reaction, there is a change in the composition of the substances in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition.