DNA testing which I think is the largest breakthrough.
Answer:
Mercury responds to temperatures differently than water. When mercury is cold, the molecules bunch together, making it seem to be less liquid, and the opposite happens during heat.
Hope this helps!
Answer:
The particles begin to vibrate faster and more.
Explanation:
Adding heat to matter increases the energy, thus creating more movement. Eventually, the bucket will melt, turning to a liquid. While it is a sold, it still has particle movement, just not enough to break volume or shape.
Answer:
The correct answer is 574.59 grams.
Explanation:
Based on the given information, the number of moles of NH₃ will be,
= 2.50 L × 0.800 mol/L
= 2 mol
The given pH of a buffer is 8.53
pH + pOH = 14.00
pOH = 14.00 - pH
pOH = 14.00 - 8.53
pOH = 5.47
The Kb of ammonia given is 1.8 * 10^-5. Now pKb = -logKb,
= -log (1.8 ×10⁻⁵)
= 5.00 - log 1.8
= 5.00 - 0.26
= 4.74
Based on Henderson equation:
pOH = pKb + log ([salt]/[base])
pOH = pKb + [NH₄⁺]/[NH₃]
5.47 = 4.74 + log ([NH₄⁺]/[NH₃])
log([NH₄⁺]/[NH₃]) = 5.47-4.74 = 0.73
[NH₄⁺]/[NH₃] = 10^0.73= 5.37
[NH₄⁺ = 5.37 × 2 mol = 10.74 mol
Now the mass of dry ammonium chloride required is,
mass of NH₄Cl = 10.74 mol × 53.5 g/mol
= 574.59 grams.
The Kj of heat that are needed to completely vaporize 1.30 moles of H2O if the heat of vaporization for water is 40.6 Kj/mole is calculated as below
Q(heat) = moles x heat of vaporization)
=1.30 mol x40.6 kj/mol= 52.78 Kj is needed
