This question includes four answer choices:
A. definite volume, highest molecular motion, highest kinetic energy
B. indefinite volume, least molecular motion, highest kinetic energy
C. definite volume, least molecular motion, lowest kinetic energy
D. definite volume, no molecular motion, lowest kinetic energy
Solids do not have the highest molecular motion (on the contrary they have the least molecular motion), so you can discard option A. Solids have a definite volume and the highest kinetic energy (given that they have the least molecular motion), so you discard option C. Molecules always have a vibrational motion, so you discard option D. Option C, have only characteristics that correctly describes a solid: definite volume, least molecular motion, lowest kinetic energy. Therefore, the answer is the option C.
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The mass of ammonium chloride that must be added is : ( A ) 4.7 g
<u>Given data :</u>
Volume of water ( V ) = 250 mL = 0.25 L
pH of solution = 4.85
Kb = 1.8 * 10⁻⁵
Kw = 10⁻¹⁴
Given that the dissolution of NH₄Cl gives NH₄⁺⁺ and Cl⁻ ions the equation is written as :
NH₄CI + H₂O ⇄ NH₃ + H₃O⁺
where conc of H₃O⁺
[ H₃O⁺ ] =
and Ka = Kw / Kb
∴ Ka = 5.56 * 10⁻¹⁰
Next step : Determine the concentration of H₃O⁺ in the solution
pH = - log [ H₃O⁺ ] = 4.85
∴ [ H₃O⁺ ] in the solution = 1.14125 * 10⁻⁵
Next step : Determine the concentration of NH₄CI in the solution
C = [ H₃O⁺ ]² / Ka
= ( 1.14125 * 10⁻⁵ )² / 5.56 * 10⁻¹⁰
= 0.359 mol / L
Determine the number of moles of NH₄CI in the solution
n = C . V
= 0.359 mol / L * 0.25 L = 0.08979 mole
Final step : determine the mass of ammonium chloride that must be added to 250 mL
mass = n * molar mass
= 0.08979 * 53.5 g/mol
= 4.80 g ≈ 4.7 grams
Therefore we can conclude that the mass of ammonium chloride that must be added is 4.7 g
Learn more about ammonium chloride : brainly.com/question/13050932
Answer: D. the hardening of liquid magma that leads to igneous rock
Explanation:
Answer : For the experiment to study the diffusion across the semi permeable membrane, following are the safety steps that will help to handle chemicals safety;
- Use droppers to transfer small amounts of chemicals into another glassware, it will prevent the unnecessary spillage of the chemical.
- Use tongs to move hot objects as they may cause severe burns.
- Check the test tubes for chips prior to using them otherwise it may leak the chemical inside it
- Washing your hands after you finishing the lab experiment, this will ensure that food is not contaminated while consuming, with the chemicals that were stuck on the hands.