Write the equality and conversion factors, and identify the numbers as exact or give the number of significant figures for which of the following:A. The Daily Value (DV) for iodine is 150 mcg.B. The nitrate level in well water was 32 ppm.C. Gold jewelary contains 58% gold by mass.D. The price of a litre of milk is $1.65.
What is the pH of a weak acid that is 0.2% ionized in a 0.2 M solution?
Answer:
pH=3.40
Explanation:
For this question, we can start with the general ionization reaction of a general acid:
[tex]HA~<->~A^-~+~H^+[/tex]
The acids can produce the hydronium ion ([tex]H^+[/tex]). If we can to calculate the pH we have to use the equation:
[tex]pH=-Log[H^+][/tex]
So, if we want to calculate the pH value we have to know the concentration of the hydronium ion. For this, we can check the percentage of ionization. If we have 0.2 % of ionization, we will have only 0.2 % of hydronium ions from the initial concentration. In other words, we can calculate the concentration of [tex]H^+[/tex], if we do the 0.2% of the initial concentration, so:
[tex]0.2~M*\frac{0.2}{100}~=~0.0004~M[/tex]
With the concentration we can calculate the pH:
[tex]pH=-Log[0.0004~M]~=~3.40[/tex]
The pH value is 3.40
I hope it helps!
Which phrase describes an irregular galaxy?
What is a substance?
ASAPPP
Answer:
A particular kind of matter
Explanation:
Which set contains non-equivalent members?A) enthalpy and heat contentB) endothermic reaction and +HC) exothermic reaction and -HD) kinetic energy and energy of motionE) high energy and high stability
Answer:
E
Explanation:
Here in this question, what we will do is to select which of the pairs that do not correlate.
A. Enthalpy and heat content
This two terms are at par with each other. By definition, the enthalpy of a system simply is the total amount of heat content it has.
B. Endothermic reaction and +H
These two terms are at par with each other. An endothermic reaction is one in which heat is absorbed from the surroundings. It has a positive value for the heat content i.e the enthalpy is positive and thus H is positive.
C. Exothermic reaction and -H
An exothermic reaction is one in which heat is released to the environment. It usually has a negative value for the enthalpy and thus the value of H is negative.
D. High energy and High Stability
These two terms are not at par. When an entity has or is of high energy, it is usually unstable. An entity at a higher energy level will not be stable until it goes to a lower level of energy.
Thus higher energy level is associated with lesser stability while lower energy levels are associated with higher stability. The lesser the energy of an entity, the higher its stability.
This makes the option our answer.
An object has a mass of 295 lbs. Convert this into kilograms (show work) ((last question))
Explanation:
kg = Ibs/2.2046 (from internet)
kg = 295/2.2046
= 133.81 kg
Which element has a greater
ionization energy Manganese (Mn) or Selenium (Se)?
Answer:
manganese has greater ionization energy than Selenium
Place the following substances in order of increasing vapor pressure at a given temperature.
a. NF3,
b. NH3,
c. BCl3.
Answer:
NH3 < NF3 < BCl3
Explanation:
The vapour pressure of a substance has something to do with the nature of intermolecular forces between its molecules. If the molecules of a substance are held together by strong intermolecular forces, the substance will display a low vapour pressure at a given temperature and vice versa.
Ammonia has the lowest vapour pressure because of strong intermolecular hydrogen bonds that hold its molecules together.
The trend for increasing vapor pressure will be:
NH₃<NF₃<BCl₃
We know that,
The stronger the intermolecular forces, the lower the vapor pressure, and the higher the boiling point.
Thus to solve this question we need to look the intermolecular attractions in the given molecules.
1. In ammonia molecule, since it is polar in nature. It exhibits, dipole-dipole interactions and also there is hydrogen bonding between nitrogen and hydrogen atoms. So these interactions are strongest thus NH₃ will have lower value of vapor pressure.
2. Forces of attractions in NF₃ is also stronger in comparison to BCl₃ but weaker than NH₃ thus in terms of vapor pressure it will come after NH₃.
3. Lastly, in BCl₃ it is a non-polar molecule; it exhibits London forces which are the weakest thus it will have the higher value of vapor pressure.
Trend for intermolecular attraction:
ion-dipole>hydrogen bonding>dipole-dipole> London forces > Van der Waals forces
Therefore,
Increasing order of vapor pressure will be:
NH₃<NF₃<BCl₃
Learn more:
https://brainly.com/question/14220340
What is the systematic name of Mg(NO3)2?A) Manganese nitrite.B) Magnesium nitrite.C) Magnesium nitrate.D) Manganese nitrate.
An atom has 17 protons and 18 neutrons.
Which symbol represents that atom, including its mass number?
Question 15 options:
Cl-32
Cl-35
S-34
Ar-33
Answer: Cl-35
Explanation:
Question 2
1 pts
Which value below correctly expresses the answer to this calculation:
(Reminder: consider sig figs)
310 x 0.00189 x 42.0 =
A 1.00-mole sample of C6H12O6 was placed in a vat with 100 g of yeast. If 32.3 grams of C2H5OH was obtained, what was the percent yield of C2H5OH?
Answer:
y = 35.06 %.
Explanation:
The reaction of fermentation is:
C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ (1)
From the reaction (1) we have that 1 mol of C₆H₁₂O₆ produces 2 moles of C₂H₅OH, then the number of moles of C₂H₅OH is:
[tex]n = \frac{2 moles C_{2}H_{5}OH}{1 mol C_{6}H_{12}O_{6}}*1 mol C_{6}H_{12}O_{6} = 2 moles C_{2}H_{5}OH[/tex]
Now, we need to find the mass of C₂H₅OH:
[tex]m = n*M = 2 moles*46.07 g/mol = 92.14 g[/tex]
Finally, the percent yield of C₂H₅OH is:
[tex] \% = \frac{32.3 g}{92.14 g}*100 = 35.06 \% [/tex]
Therefore, the percent yield of C₂H₅OH is 35.06 %.
I hope it helps you!
The percent yield of C2H5OH should be 35.06% also it have the 1.00 moles.
Calculation of the percent yield:Since
The reaction of fermentation should be
C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ (1)
Here 1 mol of C₆H₁₂O₆ generated 2 moles of C₂H₅OH, so the number of moles of C₂H₅OH should be
= 2 moles / 1mole * 1 mole
= 2 moles C₂H₅OH
So here the percent yield should be
= 32.3 / (2 * 4607)
= 32.3 / 92.14
= 35.06%
Hence, The percent yield of C2H5OH should be 35.06% also it have the 1.00 moles.
Learn more about moles here: https://brainly.com/question/19669595
The table below shows air pressure measurements taken at set altitudes above sea level. What fact about Earth’s atmosphere best explains this data according to the table? Question 3 options: As altitude increases in the atmosphere, temperature changes from layer to layer. As altitude increases, there is less air pushing down from above, which decreases the pressure. As altitude increases, the composition of the atmosphere changes so that lighter-weight gases make up the majority of the air. At higher altitudes, there is less water vapor in the air which changes the air pressure.
Answer: As altitude increases, there is less air pushing down from above, which decreases the pressure.
Explanation:
Atmospheric pressure is the result of air particles being pulled to the surface of the Earth by gravity. As they are pulled, they will exert more pressure on the Earth and this is what atmospheric pressure is.
It makes sense therefore that as we move higher into the atmosphere, the atmospheric pressure will decrease because less air particles are exerting pressure as we go further off the ground.
Another way to look at it is that there is air in the earth's atmosphere and all that air has weight that is pushing down on us. As we go higher into the atmosphere, there'll be less air pushing down on us so the weight will be less.
Answer:
A as te altitude increases
Explanation:
One gallon of gasoline in an automobiles engine produces on average 9.50 kg of carbon dioxide, which is a greenhouse gas; that is, it promotes the warming of Earth's atmosphere. Calculate the annual production of carbon dioxide in kilograms if there are exactly 40.0 million cars in the United States and each car covers a distance of 7930 mi at a consumption rate of 23.6 miles per gallon. Enter your answer in scientific notation.
Answer:
The value is [tex]U =1.3908 *10^{11} \ kg [/tex]
Explanation:
From the question we are told that
mass of carbon dioxide produced by one gallon of gasoline is [tex]m = 9.50 \ kg[/tex]
The number of cars is [tex]N = 40 \ million = 40 *10^{6} \ cars[/tex]
The distance covered by each car is [tex]d = 7930 \ mi[/tex]
The rate is [tex]R = 23.6 \ mi/ gallon[/tex]
Generally the amount of gasoline used by one car is mathematically represented as
[tex]G = \frac{d}{R}[/tex]
=> [tex]G = \frac{7930}{23.6}[/tex]
=> [tex]G = 366 \ gallons [/tex]
Generally the amount of gasoline used by N cars is
[tex]H = N * G[/tex]
=> [tex]H = 40*10^{6} * 366[/tex]
=> [tex]H = 1.464*10^{10} \ gallons [/tex]
Generally the annual production of carbon dioxide is mathematically represented as
[tex]U = m * H[/tex]
=> [tex]U =9.50 * 1.464*10^{10}[/tex]
=> [tex]U =1.3908 *10^{11} \ kg [/tex]
What is the scientific method and how does it work?
Answer:
scientists use the scientific method to collect measurable, empirical evidence in an experiment related to a hypothesis. The process of the scientific method involves making conjectures.
How many millimoles of Cr2O72- ions and K1+ ions are present in 483. mL of a 0.0750 M K2Cr2O7?1. mmolCr2O72-
2. mmol K1+
Answer:
72.45 mmol K⁺ and 36.225 mmol Cr₂O₇²⁻
Explanation:
It is possible to obtain millimoles of a substantce by the multiplication of molarity times milliliters of the solution.
In the solution that is 0.0750M K₂Cr₂O₇:
K⁺ = 0.0750M * 2 = 0.150M
Cr₂O₇²⁻ = 0.0750M
The millimoles of these ions are:
Millimoles K⁺:
483mL * 0.150M = 72.45 mmol K⁺
Millimoles Cr₂O₇²⁻:
483mL * 0.075M = 36.225 mmol Cr₂O₇²⁻
What phase would this substance be in at a pressure of 1.25atm and a temperature of 700C
Answer:
i dont have much detail, but im pretty sure it would be at a boil/vaporizing phase.