Question:
A sample of gas at 0.500 atm is transferred from a 20.0 L tank to a 12.0 L tank. What is the new pressure of the gas?
A gas occupies 4.00 L at 2.00 atm pressure. At what pressure would the volume be 6.00 L if the temperature remains constant?
Answer
- A sample of gas at 0.500 atm is transferred from a 20.0 L tank to a 12.0 L tank. What is the new pressure of the gas?
Answer = Pf = 0.833 atm
A gas occupies 4.00 L at 2.00 atm pressure. At what pressure would the volume be 6.00 L if the temperature remains constant?
Answer = Final Pressure = 1.33 atm
Explanation:
A sample of gas at 0.500 atm is transferred from a 20.0 L tank to a 12.0 L tank. What is the new pressure of the gas?
Boyle's law
PiVi = PfVf
P initial = 0.5 atm
V initial = 20 L
P final = ?
V final = 12 L
0.5 * 20 = Pf * 12
10 = Pf * 12
Pf = 10 / 12
Pf = 0.833 atm
A gas occupies 4.00 L at 2.00 atm pressure. At what pressure would the volume be 6.00 L if the temperature remains constant?
PiVi = PfVf
Pi = 2 atm
Vi = 4 L
Pf = ?
Vf = 6 L
2 * 4 = Pf * 6
8 = Pf * 6
Pf = 8 / 6
Final Pressure = 1.33 atm
Question:
Which of the following compounds are soluble in water"
- C2H5OH
- C25H52
- NaCl
- C5H12
Answer
Explanation:
Ethanol is soluble in water. Ethanol has a polar -OH group which hydrogen bonds to water making ethanol soluble. water is polar and will only dissolve polar compounds. All the other compounds in the options above are polar and none can form hydrogen bond with water. Carbon chains for instance, are non polar and would repel water molecules.
Question:
How many moles of carbon monoxide are produced when 40.0g of oxygen react completely?
- A) 0.625 mol
B)1.25 Mol
C)2.50 mol
D)80.0 mol
Answer
Explanation:
Reaction for formation of carbon monoxide
2C(s) + O2(g) → 2CO(g)
According to the equation, one mole of oxygen forms 2 moles of carbon monoxide
40 grams of oxygen reacts completely
Moles of oxygen = mass / molar mass
40 grams / 32 g/mol = 1.25 moles
If 1 mole of oxygen forms 2 moles of CO
1.25 moles of oxygen forms ?
1.25 moles * 2 / 1 = 2.5 moles of carbon monoxide
Question:
balanced equation for the reaction between propene (C3H6) and oxygen gas.
Answer
- The balanced reaction between propene and oxygen gas is as follows
2C3H6 (g) + 9O2 (g) ---> 3CO2(g) + 3 H2O (g)
Explanation:
Combustion of alkenes in oxygen forms carbon dioxide and water.
2C3H6 (g) + 9O2 (g) ---> 3CO2(g) + 3 H2O (g)
Balancing the equation requires counting the number of atoms of each element on both sides and determine what coefficient to add before each compound
In the above reaction, the coefficients that would balance the equation are 2, 9, 3, and 3 respectively.
Question:
The founder of scientific management was
A.
Frederick Taylor
B.
Henri Fayol
C.
Elton Mayo
D.
Chester Barnard
6.
The first management principles were
developed by
Answer
- The founder of scientific management was
Frederick Taylor
6.
The first management principles were
developed by
B.
Henri Fayol
Explanation:
Principles of management is the means of getting things done through others. Fundamental notion of principles of management was developed by French management theorist Henri Fayol (1841-1925). He is credited for the original planning-organizing-leading-controlling framework which is still the dominant framework in the world today.
Scientific management theory was developed by Frederick W. Taylor (1856-1915). This theory seeks to improve an organization's efficiency by enhancing task completion through scientific, engineering, and mathematical analysis.
The second shell in the ground state of argon contains ___ electrons
Answer
Explanation:
Argon has a maximum of 18 electrons
The first shell can hold up to 2 electrons
The second shell can hold up to 8 electrons
The third shell can hold up to 18 electrons'
The electron configuration of argon is 2:8:8
The second shell therefore has 8 electrons
Answer
- Mass of helium = 44 grams
Explanation:
Use the ideal gas law to calculate the mass of helium in 5.22 L of the gas at 0.918 ATM and 25°C.
Ideal gas law
PV = nRT
P = 0.918 atm
V = 5.22 L
n = moles
R = 0.0821 liter·atm/mol·K
T = 25°C. + 273 = 298 K
(0.918 * 5.22) = n * (0.0821 * 298)
n = (0.0821 * 298) / (0.918 * 5.22)
n = 24.466 / 4.792
n = 5.11 moles
Moles = mass / molar mass
5.11 = mass / 4 g/mol
Mass = 4 * 5.11 = 20.44 grams
Question:
What receptor does Clonidine act on?
Alpha 1
Alpha 2
Beta 2
Beta 1
Answers
Explanation:
Clonidine acts on alpha 2 receptors on the brain stem. These receptors works by reducing peripheral resistance which in turn decreases resistance of flow of blood in the arteries. When resistance to blood flow in the arteries decreases, blood pressure decreases as a result.
Question:
Which of the following compounds would be most water soluble?
Group of answer choices
CH3-CH2-CH3
CH3-CH2-CH2-CH2-CH2-OH
CH3-CH2-CH=CH-CH3
CH3-CH2-CH2-OH
Answer
Explanation:
- As a rule, polar dissolves polar and nonpolar dissolves nonpolar
- CH3-CH2-CH3 is alkane and completely nonpolar, hence insoluble in water
- CH3-CH2-CH=CH-CH3 is alkene which is also non-polar hence insoluble in water
- Water is polar, hence it attracts OH group and carbon chain is nonpolar hence repelled. Small alcohols are completely soluble in water but as the length of the hydrocarbon chain increases, solubility decreases. Based on this, CH3-CH2-CH2-CH2-CH2-OH will be less soluble than CH3-CH2-CH2-OH.
Question:
All the following classes of compounds contain oxygen except:
Group of answer choices
alcohols
ethers
alkynes
phenols
aldehydes
Answer
Explanation:
Alkynes are organic molecules which are made up of carbon-carbon triple bonds with formula CnH2n−2. Alkyne is a type of hydrocarbon which means the molecule is made up of only carbon and hydrogen. The other molecules contain oxygen in their structure as shown below:
- Alcohols = CnH2n+1OH.
- Ethers = R-O-R
- phenols = C6H5OH
- Aldehydes = RCHO
Question:
If 5.0 grams of KCl is dissolved in 200 mL of water, what is the concentration of the resulting solution?
Group of answer choices
0.04% (m/v)
2.5% (m/v)
1.0% (m/v)
0.025% (m/v)
10% (m/v)
Answer
Explanation:
If 5.0 grams of KCl is dissolved in 200 mL of water, what is the concentration of the resulting solution?
To calculate w/v % concentration:
w/v (%) = mass of solute (g) / volume of solution (mL) × 100
Mass of the solute = 5.0 grams
Volume of the solution = 200 mL
Concentration = 5.0 grams / 200 mL * 100 = 2.5%
Weight/Volume concentration = 2.5% (m/v)
Question:
Lipoproteins function to:
Group of answer choices
dissolve polar lipids for excretion
metabolize lipids into new substances
dissolve polar lipids in urine
transport nonpolar lipids to body cells
Answer
- transport nonpolar lipids to body cells
Explanation:
Lipoproteins are biochemical assemblies whose primary purpose is to transport hydrophobic or non-polar lipid molecules in water. To form lipoprotein, nonpolar lipids combines with apolipoproteins. Examples of lipoproteins include HDL, LDL, IDL, VLDL and chylomicrons.
Fats are generally insoluble in water, so it is hard to transport them on their own in extracellular water like plasma. Therefore, to enable easier solubility in plasma, lipid are surrounded with polar or hydrophilic shell to act as transport vehicles.
Question:
Calculate the density of alcohol in g/mL. A volume of 100 mL has a mass of 78.5 g.
Answer
Explanation:
Density = Mass / Volume
Mass = 78.5 g
Volume = 100 mL
Density = 78.5 grams / 100 mL
= 0.785 g/mL
Question:
In what condition would an increased level of serum albumin be expected
malnutrition
acute inflammation
dehydration
renal disease
Answer
Explanation:
Albumin levels rise when a person is dehydrated. Albumin is the most predominant protein in the serum and is produced in the liver and secreted directly to the circulation. When there is less water in the body, the plasma decrease in quantity and hence becomes more concentrated with plasma proteins like albumin which forms the major part of plasma.
Question:
Which of the following corresponds to the lowest point in an energy diagram for an endothermic chemical reaction?
a products
b transition state
c reaction enthalpy
d reactants
e more info is needed
Answer
Explanation:
Endothermic reaction is one which uses energy to form products. In the diagram, the reactants are at a lower energy level compared to the products. Endothermic reactions are non-spontaneous because the reaction produces products which are higher in energy than the reactants which is why the change in enthalpy is positive.
Question:
As part of an experiment, you need to make 150 mL of a 0.750 M ammonium hydroxide solution from an existing stock solution with a concentration of 9.25 M. What volume of concentrated ammonium hydroxide is required?
Answer
- Volume of concentrated ammonium hydroxide required = 16 mL
Explanation:
9.25 M stock solution
150 mL of a 0.750 M ammonium hydroxide solution
Formula
M1V1 = M2V2
M1 = Molarity of stock solution
V1 = Volume of concentrated stock solution needed
M2 = 0.750 M ammonium hydroxide solution
V2 = 150 mL ammonium hydroxide solution
9.25 M * V1 = 0.750 M * 150 mL
V1 = ( 0.750 M * 150 mL ) / 9.25 M = 12.16 mL
Volume of the stock solution (concentrated ammoinum hydroxide) needed = 12.16 ml
Question:
What happens to the volume of a gas in a closed container if the temperature increases, but the pressure remains the same? Explain.
Answer
- When temperature increases, the volume of the gas increases.
This follows Charles law which states that when pressure of a gas is held constant, volume is directly proportional to the temperature. The explanation is that at high temperature, the molecules hit the walls of the container with more force and if the container can increase in volume, then gas volume will increase as well.
Explanation:
This is in accordance to Charles law which states that the volume of a gas is directly proportional to the temperature when pressure is held constant. This means that in a closed container with gas, as temperature increases, the volume of the gas increases as well and when temperature decreases the volume of the gas would decrease.
Question:
Which of the following statements about subatomic particles is correct? [F20]
Group of answer choices
neutrons have a charge of 0 and a mass of approximately 0 amu
electrons have a charge of -1 and a mass of approximately 1 amu
an atom always contains at least as many protons as neutrons
an atom always contains at least as many neutrons as protons
the electron is the subatomic particle that participates in chemical reactions
Answer
- the electron is the subatomic particle that participates in chemical reactions
Explanation:
At the central part of the atom, neutrons and protons cluster together while electrons orbit the nucleus. What determines the chemical properties of atoms is the electrons which are negatively charged. Electrons can be shared between atoms, to fill the empty shell on the outermost energy shells of atoms participating in a chemical reaction. An atom becomes a negative ion by losing a negative electron, and a positive ion when it gains a negative electron.
Question:
What volume of water would be required to dissolve .46 moles of solute to produce a .22 M solution?
Answer
- Volume of water =1 L
Explanation:
Molarity = moles / Volume
Moles = 0.46 moles
Volume ?
Molarity = 0.22M
0.22 = 0.46 / V
V = 0.46 / 0.22
Volume of water needed = 2.1 L
Question:
Subscripts such as x, y and z are used to represent which of the following in an atom?
Select one:
a. shell
b. subshell
c. orbital
d. electron
Answer
- orbital
Explanation:
There are three possible orbitals in subshell and each adopts its own orientation. The x orbital also called Px orbital lies along the x axis. The Y orbital or Py orbital lies along the y axis and lastly the Z orbital lies along the Z axis. If the subshells are two, then it would be a Px and Py orbitals.
Question:
In what condition would an increased level of serum albumin be expected
malnutrition
acute inflammation
dehydration
renal disease
Answer
Explanation:
Albumin levels rise when a person is dehydrated. Albumin is the most predominant protein in the serum and is produced in the liver and secreted directly to the circulation. When there is less water in the body, the plasma decrease in quantity and hence becomes more concentrated with plasma proteins like albumin which forms the major part of plasma.
Question:
Which of the following corresponds to the lowest point in an energy diagram for an endothermic chemical reaction?
a products
b transition state
c reaction enthalpy
d reactants
e more info is needed
Answer
Explanation:
Endothermic reaction is one which uses energy to form products. In the diagram, the reactants are at a lower energy level compared to the products. Endothermic reactions are non-spontaneous because the reaction produces products which are higher in energy than the reactants which is why the change in enthalpy is positive.
Question:
As part of an experiment, you need to make 150 mL of a 0.750 M ammonium hydroxide solution from an existing stock solution with a concentration of 9.25 M. What volume of concentrated ammonium hydroxide is required?
Answer
- Volume of concentrated ammonium hydroxide required = 16 mL
Explanation:
9.25 M stock solution
150 mL of a 0.750 M ammonium hydroxide solution
Formula
M1V1 = M2V2
M1 = Molarity of stock solution
V1 = Volume of concentrated stock solution needed
M2 = 0.750 M ammonium hydroxide solution
V2 = 150 mL ammonium hydroxide solution
9.25 M * V1 = 0.750 M * 150 mL
V1 = ( 0.750 M * 150 mL ) / 9.25 M = 12.16 mL
Volume of the stock solution (concentrated ammoinum hydroxide) needed = 12.16 ml
Question:
What happens to the volume of a gas in a closed container if the temperature increases, but the pressure remains the same? Explain.
Answer
- When temperature increases, the volume of the gas increases.
This follows Charles law which states that when pressure of a gas is held constant, volume is directly proportional to the temperature. The explanation is that at high temperature, the molecules hit the walls of the container with more force and if the container can increase in volume, then gas volume will increase as well.
Explanation:
This is in accordance to Charles law which states that the volume of a gas is directly proportional to the temperature when pressure is held constant. This means that in a closed container with gas, as temperature increases, the volume of the gas increases as well and when temperature decreases the volume of the gas would decrease.
