Answer:
Answer: pH = 2.72
Explanation:
Calculate the pH of 0.010 M HNO2 solution. The K, for HNO2 is 4.6 x 104
In an electrical circuit, the presence of a resistor limits the current and prevents
damage related to short circuits.
True or
False
A hydrogen fuel cell is an electrochemical reactor in which oxygen and hydrogen gas are reacted to produce energy. Rather than combusting hydrogen in the presence of oxygen, the overall reaction (1/2) O2 H2 → H2O is actually carried out as two `half-reactions’ occurring at separate electrodes. To complete the reaction, this forces electrons to pass through an external circuit from one electrode to the other, and this current can be used to do work; e.g., by driving a motor. Typical operating conditions for a solid-oxide fuel cell are 500-900 C and 5-15 bar. Consider a fuel cell in which a pure oxygen stream and a pure hydrogen stream enter at 11 bar and 700 C with stoichiometric flowrates. Assume that these reactants are consumed completely, and that the water generated by the reaction leaves in a third stream at the same T and P. Assume that the fuel cell operates at steady-state with a uniform temperature of 700 C. a) Write simplified first and
Answer:
(d) Why is the fuel cell in Question (c) described as an alkaline fuel cell? (e) Another type of fuel cell uses methanol instead of hydrogen.
Explanation:
How does photosynthesis happen? (Also can anyone Pay Pal me 2 more dollars for school supplies.
Explanation:
make me brainy least pkz
Which type of cell can have a flagellum or cilia
Answer:
Both prokaryotic and eukaryotic cells contain structures known as cilia and flagella. These extensions from the cell surface aid in cell movement. They also help to move substances around cells and direct the flow of substances along tracts. Cilia and flagella are formed from specialized groupings of microtubules called basal bodies.
Explanation:
Cars are the leading cause of____
1. carbon dioxide
2. nitrogen oxide
3.carbon monoxide
pollution
Answer:
nitrogen oxide
Explanation:
Calculate the pH for the following weak acids
.01M Formic acid (HCHO2) aka= 1.7 x 10^-4
Answer:
pH = 2.88
Explanation:
For a weak acid solution, the pH can be calculated using the following formulas:
[H⁺] = [tex]\sqrt{Ka*C}[/tex]pH = -log[H⁺]Where Ka = [tex]10^{-pKa}[/tex] and C is the molar concentration.
We are given Ka and C by the problem, meaning we can now proceed to calculate [H⁺]:
[H⁺] = [tex]\sqrt{1.7*10^{-4}*0.01}[/tex] [H⁺] = 0.0013 MFinally we calculate the pH:
pH = - log (0.0013) = 2.88What are the two types of bonding we have studied?
a. Metallic and covalent
b. Covalent and ionic
c. lonic and metallic
d. Molecular and metallic
PLEASE HELP!!! I will mark brainliest I am really struggling with these problems
Answer:
21883.75 Joules are required to melt the ice!
what charge does nitrogen have
Answer:
3-
Explanation:
what does dry ashing mean
What volume, in milliliters, of water is needed to make an 8.40 M solution of HCl acid using 180. grams of HCI ?
0 603 mL
O 41.4 mL
0 587 ml
0 24.1 mL
Answer:
0 587 mL
Explanation:
First we convert 180 grams of HCl into moles, using its molar mass:
180 g ÷ 36.46 g/mol = 4.94 mol HClNow we can use the number of moles and the given concentration to calculate the required volume, applying the definition of molarity:
Molarity = moles / litersLiters = Moles / molarity4.94 mol / 8.40 M = 0.588 LFinally we convert liters into milliliters:
0.588 L * 1000 = 588 mLThe closest answer is option C, 587 mL.
The volume needed to make an 8.40 M solution of HCl is 0.587 ml.
The correct option is C.
What is HCl?HCl is a strong acid. It is present in our stomach to help in digesting food.
Step1: covert 180 grams into moles
Molar mass of HCl is 36.46 g
[tex]\dfrac{180 g}{36.46 g/mol } = 4.94\; mol\; HCl[/tex]
Step2: calculate the molarity
[tex]\rm Molality = \dfrac{mol}{L}\\\\\rm L = \dfrac{4.94 mol }{8.40 M} = 0.588 L\\[/tex]
Covert the liters into ml
[tex]\dfrac{0.588 L}{1000} = 588 mL[/tex]
Thus, the volume of the solution is 588 ml., nearest is option C, 587 ml.
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Raw milk is stored at a dairy farm in a refrigerated cylindrical vat 6.50 feet wide and 12.5 feet high. If the vat contains 3.3 × 10² ft³ of milk, how many kg of milk does the vat contain, given that raw milk has a density of 1030 kg/m3?
Answer:
11.02 kg kg
Explanation:
From the question,
Density = Mass/Volume
D = m/v.................. Equation 1
Let D = Density of milk in the vat, m = mass of the milk in the vat, v = volume of the milk in the vat.
Make m the subject of the equation
m = D/v................ Equation 2
Given: D = 1030 kg/m³, v = 3.3×10² ft³ = 330×0.2832 = 93.456 m²
Substitute these values into equation 4
m = 1030/93.456
m = 11.02 kg
Density is the mass of the substance present in the unit of the volume or can be said to be equal to the ratio of the mass and the volume of the given substance or object.
31,576.71 kg of milk is present in the vat.
How to calculate the mass of the milk?Given,
Density = [tex]1030\rm \; kg/m^{3}[/tex]Volume (V) = [tex]3.3\times 10^{2} \;\rm ft^{3}[/tex]The volume in cubic feet will be converted in [tex]\rm m^{2}[/tex] as,
1 cubic feet = 0.0929 [tex]\rm m^{2}[/tex]
[tex]\begin{aligned}\rm V &= 330 \times 0.0929 \\\rm V &= 30.657\;\rm m^{2}\end{aligned}[/tex]
The formula for calculating mass form density and volume is:
[tex]\begin{aligned}\;\rm Mass (m) &= \rm Density \times Volume (V)\\\\\rm m &= 1030 \rm kg/m^{3} \times 30.657\rm m^{2}\\\\\rm m &= 31,576.71 \rm kg \end{aligned}[/tex]
Therefore, 31,576.71 kg is the mass.
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Question 5
Complete the following analogy:
Reflection nebulae : blue :: emission nebula:
Greenish-blue
Yellow
Red
Pinkish-red
Answer:
That one is tricky but i would say yellow
Explanation:
which wet land is known for the large trees in the water known as bottomland hardwoods?
A. Central Texas
B.South Texas
C. East texas
Plz help me I am timed well mark brainliest if correct!!
The dropping off of sediments in a new place is called
A chemistry student is given 3.00 L of a clear aqueous solution at 17 C . He is told an unknown amount of a certain compound X is dissolved in the solution. The student allows the solution to cool to 17 C . The solution remains clear. He then evaporates all of the water under vacuum. A precipitate remains. The student washes, dries and weighs the precipitate. It weighs 0.15 kg . Using the above information can you calculate the solubility, X, in water at 17 C.
Answer:
The right approach is "50 g/l".
Explanation:
The given values are:
Mass or solute or precipitation,
= 0.15 kg
on converting it into "g", we get
= [tex]0.15 \ kg\times \frac{1000 \ g}{1 \ kg}[/tex]
= [tex]150 \ g[/tex]
Volume of solution,
= 3.00 L
Now,
The solubility of X will be:
= [tex]\frac{Mass \ of \ X}{Volume \ of \ solution}[/tex]
On substituting the values, we get
= [tex]\frac{150}{3}[/tex]
= [tex]50 \ g /l[/tex]
The acceleration of a baseball after it is hit by a bat depends on the mass of the ball and the net force on the ball. This example best illustrates which law?
a
Newton's law of universal gravitation.
b
Newton's first law of motion.
c
Newton's third law of motion.
d
Newton's second law of motion.
Which equation is correct if the
volume of a block is 64 cm3?
A. 5 cm x 5 cm x 5 cm = 64 cm3
B. 8 cm x 4 cm x 2 cm = 64 cm3
C. 5 cm + 5 cm + 5 cm = 64 cm3
D. 8 cm + 4 cm + 2 cm = 64 cm3
Answer:
B.
Explanation:
it's B because 4 x 2 is 8 and we all know 8 x 8 is 64. So the answer is B.
The equation that is correct if the volume of a block is 64 cm³ is 8 cm x 4 cm x 2 cm = 64 cm³. The correct option is B.
What is volume?Volume is the space occupied by any three-dimensional object. The volume is also considered as the total weight of the object. The volume is calculated as mass is divided by the density.
A block will be a rectangle because it contains length, breadth, and height. The formula will be V = L x B x H
As take all the options, and multiply them, we can calculate the actual volume of the box;
5 cm x 5 cm x 5 cm = 125
8 cm x 4 cm x 2 cm = 64 cm3
5 cm + 5 cm + 5 cm = 15
8 cm + 4 cm + 2 cm = 14
So, the correct option will be B, 8 cm x 4 cm x 2 cm = 64 cm. All others are incorrect.
Thus, the correct option is B. 8 cm x 4 cm x 2 cm = 64 cm.
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A cylinder contains hydrogen gas at 20 atm. How many balloons of 500 ml capacity can be filled up completely from the gas cylinder at the external atmospheric pressure of 640 mm of Hg at constant temperature? The volume of empty cylinder is 20 liters.
Answer:
950 balloons
Explanation:
P1 = pressure inside cylinder = 20atm
P2 = pressure outside = 640mmhg = 0.842105 atm
V1= volume of cylinder =20L = 20,000 ml
V2 = volume of a single balloon= 500ml
n = number of balloons
[tex]P_{1}V_{1} =n P_{2}V_{2}\\20* 20000 =n 0.842105 * 500\\n = 950.[/tex]
Which statement is completely accurate? O Atoms of the same element always have different numbers of neutrons. O Atoms of the same element can have neutrons but exist without protons. O Atoms of the same element always have different atomic weights. O Atoms of the same element can have different numbers of neutrons.
Answer: last one is right
Explanation: atoms of same element have always same number of protons but may have several isotopes which have different number of neutrons.
The first three half live of a chemical 2 / 2 reaction are as follows 44 min, 22 min, 11 min. What is the order the reaction?
Answer correctly please
Answer:
C.
Explanation:
A balloon originally has 0.100 moles of helium and has a volume of 0.500 L. If 0.590 grams of He are added to the balloon, what will the new volume be, in L? (Assume temperature and pressure do not change.)
Answer:
1.24 L
Explanation:
Avogadro's Law
[tex]\frac{V_{1} }{n_{1} } = \frac{V_{2} }{n_{2} }[/tex]
Convert 0.590 g of He to moles.
0.590 g x (1 mol/4.00 g) = 0.1475 mol He
Add 0.1475 mol to 0.100 mol since the initial moles (n1) increases by this amount.
0.100 mol + 0.1475 mol = 0.2475 mol He
This will represent the final moles (n2)
The initial volume is given, 0.500 L. Plug in the values.
[tex]\frac{0.500 L}{0.100 mol} = \frac{V_{2} }{0.2465 mol}[/tex]
[tex]V_{2} = \frac{(0.500 L)(0.2475 mol)}{(0.100 mol)} \\V_{2} = 1.2375\\V_{2} = 1.24 L[/tex]
Taking into account the Avogadro's law, the new volume will be 1.24 L.
Avogadro's law establishes the relationship between the amount of gas and its volume when the temperature and pressure are held constant. Remember that the amount of gas is measured in moles.
This law states that constant pressure and temperature, the same amount of gas has the same volume regardless of the chemical element that forms it.
On the other hand, Avogadro's law establishes that the volume is directly proportional to the quantity of gas: if the quantity of gas increases, the volume will increase; whereas if the amount of gas decreases, the volume decreases.
Mathematically, this law states that the ratio between the volume and the quantity of gas is constant:
[tex]\frac{V}{n} =k[/tex]
Assuming that you have an initial state 1 and the conditions are modified to a final state 2, it is true:
[tex]\frac{V1}{n1} =\frac{V2}{n2}[/tex]
In this case, being the molar mass of He 4 g/mole, 0.590 grams of He are contained in the following amount of moles:
[tex]0.590 gramsx\frac{1 mole}{4 grams} =0.1475 moles[/tex]
Then, you know:
V1= 0.500 Ln1= 0.100 molesV2= ?n2= 0.100 mol + 0.1475 mol = 0.2475 mol He because 0.590 grams are added, this is 0.1475 moles, of He to the balloonReplacing in Avogadro's Law:
[tex]\frac{0.500 L}{0.100 moles} =\frac{V2}{0.2475 moles}[/tex]
Solving:
[tex]V2=0.2475 molesx\frac{0.500 L}{0.100 moles}[/tex]
V2= 1.2375 L≅ 1.24 L
Finally, the new volume will be 1.24 L.
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If you weigh 200 lbs on Mars how much would you weigh on Earth
Answer:
75.88 pounds (or 75 pounds and 14 ounces.)
How many moles are present when there are 1.00 * 10 to the 26 power
Answer:
166.11 mol
Explanation:
I hope you mean molecules
1 mol of anything is 6.02 * 10^23
x mol of anything is 1 * 10^26
1/x = 6.02 * 10^23/1 * 10^26 Cross multiply
1 * 1*10^26 = 6.02*10^23 * x Divide by 6.02*10^23
1*10^26/6.02 * 10^23 = x
x = 166.11 mol
PLEASE HELP!
A piece of metal is heated to a temperature of 50.0°C and then placed in a calorimeter containing 50.0 g of water at 27.0°C. The water temperature increases to 35.0°C. How many joules of heat were transferred from the metal to the water? (Cwater = 4.18J/g•°C)
Answer: 1672 Joules
Explanation:
The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.
[tex]Q=m\times c\times \Delta T[/tex]
Q = Heat absorbed by water = ?
c = heat capacity of water = [tex]4.18 J/g^0C[/tex]
Initial temperature of the water = [tex]T_i[/tex] = [tex]27^0C[/tex]
Final temperature of the water = [tex]T_f[/tex] = [tex]35^0C[/tex]
Change in temperature ,[tex]\Delta T=T_f-T_i=(35.0-27.0)^0C=8.0^0C[/tex]
Putting in the values, we get:
[tex]Q=50.0g\times 4.18J/g^0C\times 8.0^0C=1672J[/tex]
As heat absorbed by water is equal to the heat released by metal, the Joules of heat transferred are 1672 Joules
The daily dose for aspirin recommended by doctors is 81 mg/ day to reduce heart disease. a) In a week how many milligrams are administered? b) Convert the "weekly "milligrams to grams.
Answer:
a)567mg
b)0.567 grams
Explanation:
There are 7 days in a week, so we multiply the number of weeks by the number of daily dosage.
81mg*7=567mg
1 gram is 1000 mg
we divide 567 by 1000 to get the value in grams
b) Name three substances which can undergo sublimation and deposition respectively
solid carbon dioxide, iodine, arsenic, and naphthalene
Explanation:
Examples of substances that undergo sublimation
Examples of solids that sublime are dry ice (solid carbon dioxide), iodine, arsenic, and naphthalene (the stuff mothballs are made of).
Ms. Fremont spent last weekend grading tests . If she spent 4 min on each test , how many hours did it take her to grade all 74 tests ?
Answer:
about 5 hours
Explanation:
When doing this problem you mmust mulitiply 4 x 74 and divide the answer by 60 because 60=1 hour.