Lead is known to be a hazardous substance, particularly when ingested. According to the Environmental Protection Agency, the maximum allowable concentration of lead in bottled water is 5 parts per billion (ppb), or 5 x 10^-9 grams of lead per gram of water.
To figure out whether this sample of bottled water is within the allowable limit, we'll need to convert the allowable concentration into grams of lead per gram of water:5 x 10^-9 grams of lead / 1 gram of water = 5 x 10^-9 grams of lead/gram of water.Next, we can calculate the actual concentration of lead in the sample of bottled water:1.511 x 10^-3 grams of lead / 466.892 grams of water = 3.236 x 10^-6 grams of lead/gram of water. We can see that this is greater than the allowable concentration of 5 x 10^-9 grams of lead/gram of water, which means that the sample of bottled water is not within the allowable limit and may pose a health risk if consumed frequently.Answer:In conclusion, the sample of bottled water is not within the allowable limit and may pose a health risk if consumed frequently.
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determine how many grams of kno3 would dissolve in 100g of water at 50 degrees celcuis to make a saturated solution
The amount of KNO₃ would dissolve in 100g of water at 50 degrees celcuis to make a saturated solution is 44 g.
To create a saturated solution of KNO₃ in 100g of water at 50 degrees Celsius, the following steps should be taken:
Step 1: Find out the mass of the solvent in the saturated solution.
The solvent is water in this instance. So, using the formula for the mass of a solution, we can calculate the mass of the solvent in the saturated solution as follows:
Mass of solvent = Mass of solution - Mass of solute
= 100 g - Mass of KNO₃
Step 2: Determine the amount of solute that would be dissolved in the solution to make it saturated.
The mass of KNO₃ that would dissolve in 100 g of water at 50°C to create a saturated solution is 56g/100g of water.
Step 3: Calculate the mass of KNO₃ that would dissolve in 100g of water to make a saturated solution.
Mass of KNO₃ = Solubility of KNO₃ × Mass of solvent
Mass of KNO₃ = 56 g/100 g × (100 g - Mass of KNO₃)
Now, let's solve for Mass of KNO₃;
56 = 56g(100-Mass of KNO₃)/100100 - Mass of KNO₃ = 100
Multiply both sides of the equation by 100 to obtain;
5600 - 100 Mass of KNO₃ = 100
Mass of KNO₃ = 5600/10100 - 56
= 44 g
Therefore, 44 g of KNO₃ would dissolve in 100g of water to make a saturated solution.
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a) Water has a molar mass of 18 g/mol and a density of 1000 kg/m3 (or 1 g/cm3). Based on this data, estimate the number of water molecules per unit surface area of water.
b) The coordination number of water (i.e., the average number of "neighbors" each water molecule has) in the liquid state is 4. Neighboring water molecules attract each other via hydrogen bonds, each of which has a binding energy of roughly 10–20 J (although this number depends relatively strongly on temperature). Use this information to estimate the surface tension of water. How does your estimate compare to the observed figure (
γ water = 0.072 N/m ) (hints: Keep in mind that we can think of
surface tension as surface energy per unit area, and consider the energy needed to bring a molecule from the bulk to the surface)?
The estimate is still useful because it provides insight into the behavior of water molecules at the surface of the liquid.
Molar mass of water, M = 18g/molDensity of water, ρ = 1g/cm³ = 1000kg/m³The number of molecules per unit surface area of water can be estimated as follows:Number of water molecules per unit volume of water = Avogadro's number, NA / MNumber of water molecules per unit volume of water = 6.022 × 10²³ / 18 = 3.345 × 10²² / molThe number of molecules per unit surface area of water = the number of molecules per unit volume of water × the thickness of the water layer on the surface= 3.345 × 10²² / m³ × 1 × 10⁻⁸ m= 3.345 × 10¹⁴ / m²b)Given:Coordination number of water, CN = 4Binding energy of hydrogen bond, E = 10⁻²⁰ JThe surface tension of water, γ water = 0.072 N/mEnergy required to bring one molecule from the bulk of the liquid to the surface of the liquid, ΔE= γ water × AThe total binding energy of a water molecule in the liquid state = the binding energy of one hydrogen bond × the coordination number= 10⁻²⁰ J/bond × 4 bonds = 4 × 10⁻²⁰ JThe number of molecules per unit surface area of water = the energy required to bring one molecule from the bulk of the liquid to the surface of the liquid / the total binding energy of a water molecule in the liquid state= ΔE / 4 × 10⁻²⁰= 0.072 / (4 × 10⁻²⁰)= 1.8 × 10²⁰The surface tension of water can also be expressed as follows:γ water = (N / A) × EThe number of hydrogen bonds per unit area, N / A = γ water / E= 0.072 / 10⁻²⁰ = 7.2 × 10¹⁸ / m²The difference between the estimated value and the observed value is relatively large (about a factor of 25). It is because this is just an estimate, and it does not consider all the factors affecting the surface tension of water. However, the estimate is still useful because it provides insight into the behavior of water molecules at the surface of the liquid.
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for a particular redox reaction, mno2 is oxidized to mno−4 and ag is reduced to ag . complete and balance the equation for this reaction in basic solution.
The given redox reaction can be represented in the following way: MnO₂ → MnO⁴⁻ + Ag → Ag+
To balance the redox reaction, the following steps are to be followed:
1: First, balance the net ionic equation with the help of half-reactions:
MnO2 → MnO⁴⁻+ e- [Oxidation Half-Reaction]
Ag+ + e- → Ag [Reduction Half-Reaction]
2: Determine the number of electrons that are required to balance the half-reactions. The oxidation half-reaction requires five electrons.
MnO₂ → MnO⁴⁻+ 5e-
The reduction half-reaction requires one electron.
Ag+ + e- → Ag
3: Find the least common multiple of the electrons required in the half-reactions, and use it to balance the equation. The least common multiple of 5 and 1 is 5. To balance the equation, multiply the oxidation half-reaction by 1 and the reduction half-reaction by 5. This will give us the following balanced equation:
5MnO₂ + 16H₂O + Ag → 5MnO⁴⁻ + 8OH- + 4Ag+
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Which of the following statements is not true? a. Water is polar. b. Water stabilizes temperature. c. Water is essential for life. d. Water is the most abundant atom in Earth’s atmosphere.
Answer: d. Water is the most abundant atom in Earth’s atmosphere.
Explanation:
Water percentage in the atmosphere is 0.001 percent only as it not the major reservoir or source of water. The water is available in the atmosphere in the form of water vapors. These water vapors when aggregate and their concentration becomes high they fall down as rain on earth so the rain is collected in water reservoirs like oceans, rivers, lakes, ponds, aquifers, and other sources of water, which are the components of hydrosphere on earth. So, hydrosphere is most abundant in water. Moreover, water is not an atom instead it is the molecule formed by the combination of two molecules of hydrogen and one molecule of oxygen.
Answer it right for a brainliest
Answer:
plz I. need a brainliest
Explanation:
I hope you have a good day
If 0=30° then verify that sin20=2sin0.cos0
Answer:
It is proved that sin20=2sin0.cos0
Explanation:
Given
[tex]0=30[/tex] °
[tex]sin20=2sin0.cos0[/tex]
Substituting the value of "0" on both the sides, we get -
[tex]sin2 (30) =2sin 30 * cos 30\\sin 60 = 2 * sin 30 * cos 30 \\0.866 = 2 * 0.5 * 0.866\\0.866 = 0.866[/tex]
Since LHS = RHS
we can say that [tex]sin20=2sin0.cos0[/tex]
How are white blood cells linked to the lymphatic system?
Answer:
The lymphatic system produces white blood cells, known as lymphocytes. There are two types of lymphocyte, T cells and B cells. They both travel through the lymphatic system. As they reach the lymph nodes, they are filtered and become activated by contact with viruses, bacteria, foreign particles, and so on in the lymph fluid.
Explanation:
Are water waves transverse or longitudinal? How do you know? Own words please. No files or links either.
Answer:
Transverse waves are known by motion being perpendicular to the waves movements. Longitudinal waves move in a direction parallel to the way the wave moves. Water waves are an example of both as they move in a clockwise motion.
Explanation:
( Sorry if it is not the best answer but I did my best by researching )
what product(s) forms at the cathode in the electrolysis of an aqueous solution of k2so4?
1. Sulfur
2. H2 and OH-
3. K
4. O2 and H+
We can see here that the product(s) formed at the cathode in the electrolysis of an aqueous solution of [tex]K_{2}SO_{4}[/tex] are: 2. H2 and OH-
What is electrolysis?Electrolysis is a chemical process that involves the use of an electric current to drive a non-spontaneous chemical reaction. It is typically carried out in an electrolytic cell, which consists of two electrodes—an anode (positive electrode) and a cathode (negative electrode)—immersed in an electrolyte solution.
During electrolysis, when an electric current is passed through the electrolyte, chemical reactions occur at the electrodes.
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17. What is the molarity of ZnCl2 that forms when 15 grams of Zn reacts completely with CuCl, if a
final volume of 175 mL is produced?
Zn + CuCl2 → ZnCl2 + Cu
Answer:
1.31M
Explanation:
Based on the reaction, 1 mole of Zn produce 1 mole of ZnCl₂. As the reaction occurs completely, the moles of Zn added = Moles of ZnCl₂ produced. To find molarity we need the moles of ZnCl₂ and the volume of the solution in liters:
Moles Zn = Moles ZnCl₂ -Molar mass Zn: 65.38g/mol-:
15g * (1mol / 65.38g) = 0.23 moles of ZnCl₂
Volume in Liters:
175mL * (1L / 1000mL) = 0.175L
The molarity is:
0.23moles / 0.175L
1.31MHow much of a 0.250 M sucrose solution must be used to prepare 400.0 mL of a 0.0310 M solution? mL
Answer:
49.6 mL
Explanation:
is the answer, I just did it :)
49.6mL of a 0.250 M sucrose solution must be used to prepare 400.0 mL of a 0.0310 M solution.
What is Molarity?Molarity of a given solution is known as the total number of moles of solute per litre of the solution. A solution that is 1.00 molar (written 1.00 M) contains 1.00 mole of solute for every liter of solution.
Molarity = (No. of moles of solute ÷ Volume of solution in liters)
The unit of molarity is mol L⁻¹.
Molarity is temperature dependent because as temperature changes, volume of the solution also changes.
We can also use the formula-
M1V1 = M2V2
M1 = 0.25
V2 = 400mL
M2 = 0.0310
V1 = ?
V1 = M2V2/ M1
V1 = 49.6mL
Therefore, 49.6mL of a 0.250 M sucrose solution must be used to prepare 400.0 mL of a 0.0310 M solution.
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answer 1-5 of lesson outline for brainiest
Answer:
see explanation
Explanation:
1. mid-ocean ridge
2.gravity
3.normal,reverse
4.cools
5.stripes
6.spreading
7.continents
What mass of iron (ciron= 0.11 cal/g°C) would need 1450 cal of energy in order to raise its temperature by 19.7°C
Answer: m=Q/c*\Delta TQ/c∗ΔT = 1450cal/(0.11cal/g* 19.7ºC)=669.12 g1450cal/(0.11cal/g∗19.7ºC)=669.12g
Answer: 669.12g iron.
Explanation:
How many molecules are in
6.0 moles of methane (CH4)?
Let's begin by setting up our equation.
What belongs in the green box?
6.0 moles CHA
A. 1 mole CH4
B. 6.02 x 1023 molecules CH4
Gerald's science teacher mixed liquid X and liquid Y, both at room-temperature, in a large beaker. two beakers of clear solutions to the left of a right-pointed arrow, and a large beaker with a clear solution to the right of the arrow The mixture in the large beaker still looked clear like water, but when the students, one at a time, carefully touched the outside of the large beaker, it felt warm to the touch. Why did the large beaker most likely feel warm? A. The two liquids were not soluble in water. B. The release of a gas heated the solution. C. A chemical reaction produced a new substance. D. The energy of mixing warmed the liquids.
Answer:
c
Explanation:
A chemical reaction produced a new substance. In a chemical reaction, the atoms that make up the reactants are rearranged to produce various products.
What is chemical reaction?chemical reaction, the transformation of one or more chemicals (the reactants) into one or more distinct compounds (the products). Chemical elements or chemical compounds make up substances.
A chemical reaction is one in which two or more reactants will react to form a new substance. When new substance will form it will produce heat. Therefore, when science teacher was mixing two liquids it was generating heat.
Heating a substance allow molecules to move faster. When heat is given to the object it will move fast. When heat will apply to a solid it will turn into liquid. When heat is supplied to the liquid it will turn into gas.
Therefore, A chemical reaction produced a new substance. In a chemical reaction, the atoms that make up the reactants are rearranged to produce various products.
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Which is a function common to both the muscular and skeletal systems?
Answer:
please give me brainlist and follow
Explanation:
In the musculoskeletal system, the muscular and skeletal systems work together to support and move the body. The bones of the skeletal system serve to protect the body's organs, support the weight of the body, and give the body shape.
Answer:
B. bending of the arm
Explanation:
Do noble gases form bonds? Why or why not?
◕‿↼ Hey There!
Answer → Source Noble Gases have a full valence shell, which is why they rarely form bonds with other atoms.
✨ Hope This Helps!✨
In addition to showing the ratio of atoms in a molecule, what else do the subscripts in a formula tell us?
Answer:
See explanation
Explanation:
Usually, when we write a chemical formula for any compound or other chemical specie, we use subscripts to;
Indicate the ratio of atoms of each element present in the compound or chemical specieShow the number of atoms of each element present in the compound or chemical specie.Hence, the subscripts written after chemical formulas have more than one function as described above.
In H2SO4 for instance, there are two hydrogen atoms, one sulphur atom and four oxygen atoms as shown in the chemical formula.
A truck has a kinetic energy of 1200j and is traveling at 9 m/s what is the truck mass
Answer:
Mass of truck = 29.62 kg (Approx.)
Explanation:
Given:
Kinetic energy = 1200 J
Speed of truck = 9 m/s
Find:
Mass
Computation:
The kinetic energy of a thing is the force that has attributable to its movement in physics.
Kinetic energy = [1/2][m][v]²
1,200 = [1/2][m][9]²
1,200 = [1/2][m][81]
Mass of truck = 29.62 kg (Approx.)
what is an magnetic pole
Answer:
Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from the Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun.
identify the type of change (physical or chemical) that occurs when an iron bar rusts and when a substance freezes. use complete sentences to justify the type of change that occurs.
For the rusting of an iron bar, a chemical change occurs; while for the freezing of a substance , a physical change occurs.
When an iron bar rusts, a chemical change occurs. Rusting is a chemical reaction that involves the oxidation of iron in the presence of oxygen and water. The iron undergoes a chemical transformation and forms a new compound, iron oxide, which gives the rusty appearance. This change is irreversible and involves a rearrangement of atoms at the molecular level.
On the other hand, when a substance freezes, a physical change takes place. Freezing is a phase transition from a liquid to a solid state. During freezing, the substance undergoes a change in its physical state without any alteration in its chemical composition. The arrangement of molecules or atoms becomes more ordered as they transition from a disordered liquid state to a more structured solid state. This change is reversible, and the substance can return to its liquid state by melting.
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A rod, X has a positive charge of 8. An otherwise identical rod, Y has a negative charge of 4. The rods are touched together, and then separated.
1.When they touch, what particles move between them?
2.Did the particles move from "X" or "Y" or from "Y" to "X"?
Answer:
1. electrons
2. From "Y" to "X"
Explanation:
1. Electrons move between the rod since the electrons are the only charge carriers which are free to move.
2. The particles move from from "Y" to "X" since the electrons are the only charge carriers which are free to move. The positive charge on rod x is due to a deficit of electrons while the negative charge on rod Y is due to the excess of electrons. When the rods come together, the electrons move from "Y" to "X" since the electrons are the only charge carriers which are free to move.
When the molecules in a gas lose energy the gas will turn into a liquid.
A. True
B. False
Answer:
true
Explanation:
Answer:
true
Explanation:
when the temperature of the gas is decreased or pressure on the gas is increased, the gas becomes liquid at a certain temperature or pressure.
How many molecules are there in 24 grams of HSO₃?
What is the pOH of a solution whose pH is 12.41?
Answer:
1.59
Explanation:
14=pOH+pH
pOH=14-12.41
pOH=1.59
I NEED HELP THIS IS DUE TMR!
A 124.6-g sample of copper has a volume of 14 cm. what is the density of copper?
Answer:
The density of copper is 8.9 grams per cubic centimeter.
Explanation:
There is a writing mistake in statement, correct form is written below:
A 124.6 grams sample of copper has a volume of 14 cubic centimeters. What is the density of copper?
Let suppose that mass of the copper sample is distributed uniformly in its volume, then we shall use the following definition of density ([tex]\rho[/tex]), in grams per cubic centimeter:
[tex]\rho = \frac{m}{V}[/tex] (1)
Where:
[tex]m[/tex] - Mass, in grams.
[tex]V[/tex] - Volume, in cubic centimeters.
If we know that [tex]m = 124.6\,g[/tex] and [tex]V = 14\,cm^{3}[/tex], then the density of the sample of copper is:
[tex]\rho = \frac{m}{V}[/tex]
[tex]\rho = 8.9\,\frac{g}{cm^{3}}[/tex]
The density of copper is 8.9 grams per cubic centimeter.
9. Which of the following would increase the
validity of Experiment 2?
A. Testing magnets with a volume less
than 0.04
B. Testing magnets made of iron instead
of ceramic
C. Testing generators with larger
vibrations
D. Testing a generator with coils fewer
than 2050
.
is the value of an investment at the end of a specific time period. A. Compound interest B. Present value O C. Simple interest OD. Future value Which of the following recognizes the time value of money? O A. NPV B. ARR OC. Net cash flows D. Payback period
The value of an investment at the end of a specific time period is the Future value.
Future value is defined as the value of an asset or investment at a specific date in the future. It is calculated based on the present value of the investment, the interest rate, and the number of time periods. It is an important concept in finance as it recognizes the time value of money.
The time value of money recognizes that money today is worth more than the same amount of money in the future because of its earning potential. In other words, a dollar today is worth more than a dollar tomorrow because you can invest it and earn interest.
Future value takes into account the effects of compounding interest, which means that interest earned on an investment is added to the principal, and interest is earned on the new total.
On the other hand, NPV, ARR, net cash flows, and payback period are other important concepts in finance, but they do not explicitly recognize the time value of money. Net Present Value (NPV) is the difference between the present value of cash inflows and the present value of cash outflows.
ARR stands for Accounting Rate of Return, which is the average annual income from an investment over its life. Net cash flows are the total amount of cash inflows minus cash outflows. The payback period is the amount of time it takes for an investment to recoup its initial cost.
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Can someone help with 10 a and b please
Answer:
for question a element A and B are isobars
for question b element C and D have the same atomic numbers.
Explanation:
element A and B are isobars because they have the same mass numbers but different atomic numbers. The different atomic numbers is as a result of the difference in proton number of each elements A and B. (A and B are two different elements). element C and D are isotopes of the same element because they have the same atomic numbers (same number of protons) but differ in number of neutrons resulting in the different number of mass numbers. (C and D are the same elements)Which one of the following systems has the highest entropy?
10 mL of water at 100°C
10 mL of water at 50°C
10 mL of water at 10°C
Answer: a
Explanation:
The highest entropy will be 0 mL of water at 100°C.
What is entropy?Entropy is just a measured physical quality that will be most usually linked with disorder, unpredictability, or uncertainty.
The quantity of random movement in a system increases as more energy is put into it. Entropy rises like a volume increases in a system.
Therefore, the correct answer will be option 1.
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