Answer: 498.51mmHg
Explanation:
First let us analyse what was given from the question:
T1 = 425K
T2 = 275.15K
P1 = 770 mmHg
P2 =?
Using the general gas equation
P1V1/T1 = P2V2/T2
But we were told from the question that the volume is constant. So, our equation becomes:
P1/T1 = P2/T2
770/425 = P2 /275.15
Cross multiply to express in linear form:
P2 x 425 = 770 x 275.15
Divide both side by 425, we have:
P2 = (770 x 275.15) /425
P2 = 498.51mmHg
Colligative
properties calculations are used for this type of problem. Calculations are as
follows:<span>
ΔT(freezing point) = (Kf)m
ΔT(freezing point)
= 1.86 °C kg / mol (0.50 mol/kg)
ΔT(freezing point) = 0.93 °C
Tf - T = 0.93 °C
<span>T = -0.93 °C</span></span>
Answer:
The answer to your question is: letter A
Explanation:
a) A + B ⇒ AB + heat It is an exothermic reaction because heat is released.
b) A + BΔ ⇒ AB It heat added to the reactants , then it is an endothermic reaction.
c) heat + BC ⇒ B + C It's an endothermic reaction because heat is added to the reactants.
d) B + heat + CD ⇒ BD + C It's and endothermic reaction because heat is added to the reactants.
Answer:
n = 2.208x10¹⁸ photons
Explanation:
The energy of a photon( an elementary particle) is given by the equation:
E = nxhxf
Where n is the number of photons, h is plank constant (6,62x10⁻³⁴ J.s), and f is the frequency. Knowing that the power level is 0.120mW (1.2x10⁻⁴ W), the energy in J, for a time of 78 min (4680 s)
E = 1.2x10⁻⁴x4680 = 0.5616 J
The frequency of a photon is its velocity ( c= 3x10⁸ m/s) divided by its wavelength, which is 780 nm = 780x10⁻⁹ m
f = 3x10⁸/780x10⁻⁹
f = 3.846x10¹⁴ s⁻¹
Then, the number of photons is:
0.5616 = nx6,62x10⁻³⁴x3.846x10¹⁴
n = 2.208x10¹⁸ photons.
Answer:
MedlinePlus Drugs Information
Explanation:
Promethazine is in a class of medication called phenothiazines
