Answer:
3.74g of ethylene glycol must be added to decrease the freezing point by 0.400°C
Explanation:
One colligative property is the freezing point depression due the addition of a solute. The equation is:
ΔT=Kf*m*i
<em>Where ΔT is change in temperature = 0.400°C</em>
<em>Kf is freezing point constant of the solvent = 1.86°C/m</em>
<em>m is molality of the solution (Moles of solute / kg of solvent)</em>
<em>And i is Van't Hoff constant (1 for a nonelectrolyte)</em>
Replacing:
0.400°C =1.86°C/m*m*1
0.400°C / 1.86°C/m*1 = 0.215m
As mass of solvent is 280.0g = 0.2800kg, the moles of the solute are:
0.2800kg * (0.215moles / 1kg) = 0.0602 moles of solute must be added.
The mass of ethylene glycol must be added is:
0.0602 moles * (62.10g / mol) =
3.74g of ethylene glycol must be added to decrease the freezing point by 0.400°C
<em />
POH = - log [OH]
<span>pOH = - log (6.40 × 10-3) </span>
<span>pOH = 2.19 </span>
<span>pH + pOH = 14 </span>
<span>pH = 14 - pOH </span>
<span>pH = 14 - 2.19 </span>
<span>pH = 11.8</span>
Answer:
A. The human body can break down complex carbohydrates into sugar molecules that provide energy.
Explanation:
Strings of glucose, form complex carbohydrates such as starch and glycogen. Glycogen which is a stored form of glucose in humans is a source of long-term energy, and a complex carbohydrate because glycogen can be converted to glucose-1-phosphate which can enter the glycolytic cycle to generate Adenosine triphosphate which is a unit of energy.
This stored form of energy can be slowly broken down to release energy when needed by the body. During exercise, for instance, glycogen can slowly release ATP needed for energy.
Answer:
34.6 cm³
Explanation:
<em>A chemistry student needs 55.0 g of carbon tetrachloride for an experiment. By consulting the CRC Handbook of Chemistry and Physics, the student discovers that the density of carbon tetrachloride is 1.59 g/cm³. Calculate the volume of carbon tetrachloride the student should pour out. Be sure your answer has the correct number of significant digits.</em>
Step 1: Given data
- Mass of carbon tetrachloride (m): 55.0 g
- Density of carbon tetrachloride (ρ): 1.59 g/cm³
Step 2: Calculate the required volume of carbon tetrachloride
Density is an intrinsic property of matter. It can be calculated as the quotient between the mass of the sample and its volume.
ρ = m/V
V = m/ρ
V = 55.0 g/(1.59 g/cm³)
V = 34.6 cm³
The chemistry student should pour 34.6 cm³ of carbon tetrachloride.
Answer:
The correct option is;
2) Thermal energy increases by a factor of R
Explanation:
The equipartition energy theorem states that when molecules are in a state of thermal equilibrium, particles within the system posses equal average energy with each degree of freedom which can be known as energy due to a state of having a particular temperature or thermal energy given by the relation
= Kinetic energy of translation + Kinetic energy of rotation + Energy of vibration
For a mono-atomic gas, = 3/2·n·R·T
For a diatomic gas, = 5/2·n·R·T
For a solid element, = 3·n·R·T
Therefore, as the temperature is doubled, the thermal energy increases by a factor of R.
