Answer:
C.) The number after it is between 5 and 9
Explanation:
If the digit to the right is less than five, you must leave the digit you want to round to as it is.
But, if the digit to the right is greater than or equal to five, you must increase the value of the digit you're rounding to by one. And any remaining digits before the decimal point become zeros, and any that are after the decimal point are dropped.
Hope this helps you out! : )
Which of the following is a halogen?
O A. Neon (Ne)
B. Iodine (1)
O C. Oxygen (0)
O D. Potassium (K)
Answer:
[tex]\boxed{\mathrm{Iodine}}[/tex]
Explanation:
Halogens are elements in group 17 or 7 in the periodic table.
Iodine is a halogen.
Therefore, iodine, an Halogen
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What is the freezing point of a solution of 1.43 g mgcl2 in 100 g of water? Kf for water is 1.86°c/m for water.
Answer:
Change in T = i x m x kf. Where i is the number of particles the compound dissociates, m is the molality, and kf is the constant specific to water. MM of MgCl2 = 95.21 g/mol
MgCl2 will form three atoms....i = 3......1Mg + 2Cl
kf = 1.86
moles of MgCl2 = 1.43g/95.21 = 0.015
m = moles solute/ kg solvent = 0.015/.1kg = .15m
Change in T = (3)(.15)(1.86) = .838
This is the depression of the freezing point of water, it is negative because the water's new freezing point is its normal freezing point minus the change in T.
0 - .838 = -.838
Explanation:
HELP ME ASAP PLISSSSS
Answer:
In this titration, solution P (that contains hydrochloric acid) is added into the conical flask that contains sodium hydroxide drop by drop. The indicator (phenolphthalein) changes color when all the NaOH is completely neutralized.
i) Solution P contains hydrochloric acid. Hydrochloric acid is the chemical that reacts with sodium hydroxide to give salt and water.
This type of reaction is called neutralization.
ii) Under alkaline conditions, phenolphthalein appears pink in color. When the solution becomes neutral or acidic, it is colorless.
So, the color change of the mixture at the end point is from pink to colorless.
iii) same explanation from question i,
HCl (aq) + NaOH (aq) --> NaCl (aq) + H2O (l)
iv) no. of moles = volume (in dm3) x concentration
hence,
no. of moles of NaOH used = 25/1000 x 0.1
= 0.0025 mol
From the equation in (iii), since the mole ratio of HCl : NaOH = 1:1, meaning 1 mole of HCl reacts completely with 1 mole of NaOH.
This also means that the no. of moles of NaOH reacted equals to the no. of moles of HCl needed to react with it, which is 0.0025 mol.
Given the concentration of HCl in solution P is 0.1 mol /dm3. (pls correct me if I misunderstood your comment),
if v is the volume of HCl needed,
0.0025 = 0.1 v
v = 0.025 dm3
also = 25 cm3
Answer:
In this titration, solution P (that contains hydrochloric acid) is added into the conical flask that contains sodium hydroxide drop by drop. The indicator (phenolphthalein) changes color when all the NaOH is completely neutralized.
i) Solution P contains hydrochloric acid. Hydrochloric acid is the chemical that reacts with sodium hydroxide to give salt and water.
This type of reaction is called neutralization.
ii) Under alkaline conditions, phenolphthalein appears pink in color. When the solution becomes neutral or acidic, it is colorless.
So, the color change of the mixture at the end point is from pink to colorless.
Explanation:
A nursing home is installing their own bulk oxygen system due to their large volume of consumption. OSHA regulation 29 CFR 1910.104(b)(2)(iii) requires owners of bulk oxygen systems to provide noncombustible surfacing in areas where liquid oxygen might leak during operation of the system or during the filling of a storage container. If the nursing home provides an asphalt surface in areas where oxygen could potentially leak, will it be in compliance with the workplace regulation regarding oxygen? Explain your answer
Answer:
NO! It would be in violation of the workplace regulation regarding oxygen.
Explanation:
Bulk oxygen systems convey liquified oxygen which is of geat use and importance in institutions like a nuirsing home.
Liquified oxygen is gaseos oxygen that has been condensed under high presures into liquid form. It is transported via a complex system of vaporizers, storage tanks and pipes around the facility it is needed. Liquified oxygen is oxygen- rich.
Asphalt is a petroleum derivative that is often used to in coating surfaces and tarring roads.
Its primry constituent is Carbon with minor constitunets like sulphur, nirogen, oxygen. As a petrolem derivative, it is very combustible.
In the event of an oxygen leak on an asphalt surtface, oxygen acting as an oxidizing agent can combine with asphalt in the presence of air, to cause a large fire.
Hence, asphalt surfacing in areas of oxygen leaks, would not be in compliance with the workplace regulation as it has the potential of causing a fire in the nursing home.
The table shows the conditions during two trials of a reaction.
Answer:
The correct option is;
The reaction pathway for the trials is different
Explanation:
The effect of a catalyst in a chemical reaction is to increase the rate of a reaction by changing the pathway or mechanism of the reaction and/or to lower the transition state's energy thereby lowering the activation energy of the reaction
The pathway of the reaction is changed by the catalyst by the formation of intermediate compounds by the catalyst which require lower activation energy to form the products than the original non-catalyzed reactants. In the process the catalyst is regenerated, thereby, not taking part in the reaction.
A 2.00L flask was filled with 4.00 mol of HI at a certain temperature and given sufficient time to react. At equilibrium the concentration of H2 was 0.400 M. Find the equilibrium concentrations of I2 and HI and then find the Keq at this temperature.
Answer:
The equilibrium concentration of I₂ is 0.400 M and HI is 1.20 M, the Keq will be 0.112.
Explanation:
Based on the given information, the equilibrium reaction will be,
2HI (g) ⇔ H₂ (g) + I₂ (g)
It is given that 4.00 mol of HI was filled in a flask of 2.00 L, thus, the concentration of HI will be,
= 4.00 mol/2.00 L
= 2.00 mol/L
Based on the reaction, the initial concentration of 2HI is 2.00, H₂ is 0 and I₂ is O. The change in the concentration of 2HI is -x, H₂ is x and I₂ is x. The equilibrium concentration of 2HI will be 0.200-x, H₂ is x and I₂ is x.
It is given that at equilibrium, the concentration of H₂ or x is 0.400 M.
Now the equilibrium concentration of HI will be,
= 2.00 -2x
= 2.00 - 2 × 0.400
= 1.20 M
The equilibrium concentration of I₂ will be,
I₂ = x
= 0.400 M
The equilibrium constant (Keq) will be,
Keq = [H₂] [I₂] / [HI]²
= (0.400) (0.400) / (1.20)²
= 0.112
Thus, the Keq of the reaction will be 0.112.
Why are the oxidation and reduction half-reactions separated in an
electrochemical cell?
Answer:
It makes the current viable enough to pass through an exterior wire.Explanation:
Electrochemical cells primarily comprise of two half-cells. These half-cells assist in isolating the oxidation and reduction half-reactions. These two reactions are linked by a wire which allows the current to move from one edge to the other. The oxidation at the anode and the reduction take place at the cathode and the addition of a salt bridge helps in completing the circuit and permits the current to flow and leads to the generation of electricity.
hello:)!! for the preparation of salts , I don’t really understand the part where acids react with insoluble bases. do I just memorise it? :) thanks!
Answer:
I think if u will clear your topic it would be more helpful.
But if u r unable to do it, then u can just memorise it.
See, i will try to help u.
Salts are formed when acids react with bases.
and this reaction is called neutralisation reaction.
e.g. HCl+NaOH=NaCl+H2O.
It is very easy.
Other examples:
H2SO4+Mg(OH)2=MgSO4+2H2O.
There may be some other reactant with acid like u have mentioned above.
hope it helps u....
plz mark as brainliest...
During which two minute time period is the temperature of the water changing fastest? Select one: a. 0-2 minutes b. 2-4 minutes c. 4-6 minutes d. 6-8 minutes Clear my choice
Answer:
b. 2-4
Explanation:
Look at the slope of the line, between 0-2 and 4-6 the slope is only 10, but between 2-4 the slope is 20, so that's when the temperature is changing the fastest. In the same time it took for the water to increase by 20 degrees between 0-2 and 4-6, the temperature of the water increased by 40 degrees between 2-4 so that's when the change is the fastest.
Label the chemical equation.
2 Mg(s) + O2(g) → 2 MgO(s)
Label the chemical equation.
2 Mg(s) + O2(g) → 2 MgO(s)
Answer:
Kindly check Explanation
Explanation:
Given the chemical equation:
2 Mg(s) + O2(g) → 2 MgO(s)
2 molecules of Magnesium + Oxygen gas (Reactant)
→ ( yield)
2 molecules of magnesium oxide (product)
2 in Mg and MgO (coefficients)
2 in Oxygen gas (subscript)
Solid (s) - physical state of Reactant Mg
Gas (g) - physical state of Reactant O2
Solid (s) - physical state of product 2MgO
Plz solve mcqs#04 with full detailed.note
Answer:
The correct option is;
(B) 1 s², 2s², 2p⁶, 3s², 3p³
Explanation:
The electron configuration is the outline of the electron arrangement about a nucleus
In the systemic pattern of electron arrangement within an atom, there are, s, p, d, f orbitals
The maximum number of electrons in an s, p and d orbital = 2, 6, and 10 respectively
Based on Aufbau's principle the electrons are arranged based on the order of their energy level
The charge is presented by the number of electrons in the outermost shell, an element able to form an ion of charge of -3 will gain 3 electrons to complete its outermost shell
Among the options given, option B is the only option that has the capacity to take the electrons to complete the number of electrons in the p orbital outermost shell to 6 from 3, that is 3p³ + 3e⁻→ 3p⁶.
The concentration of phenylephrine hydrochloride in a prefilled syringe is 10 mg/mL. What is the percentage concentration (w/v) of phenylephrine in the injection. (Answer must be numeric; no units or commas; round the final answer to the nearest WHOLE number.)
Answer:
The percentage concentration (w/v) of phenylephrine in the injection is 1 %.
Explanation:
The percentage concentration in w/v of the phenylephrine hydrochloride can be calculated as follows:
[tex]\%^{w}/_{v} = \frac{m}{V} \times 100[/tex]
Where:
m: is the mass of the solute in grams
V: is the volume of the solution in milliliters
The concentration of the phenylephrine hydrochloride is 10 mg/mL, so the percentage concentration is:
[tex]\%^{w}/_{v} = \frac{m}{V} \times 100[/tex]
[tex]\%^{w}/_{v} = \frac{10 \cdot 10^{-3} g}{1 mL} \times 100[/tex]
[tex]\%^{w}/_{v} = 1 \%[/tex]
Therefore, the percentage concentration (w/v) of phenylephrine in the injection is 1 %.
I hope it helps you!
what will happen if a candle will be covered with an inverted jar filled will nitrogen
Answer:
The flame will burn out
Explanation:
The oxygen will be kept out of the jar, without oxygen the flame cannot last long. The flame will eventually burn out. Nitrogen gas has no role to play in the burning. Nitrogen slows down the burning rate.
(Help please!! important test!!!) What property of matter are you measuring if you are using a triple beam balance? (2 points)
volume,
gravity,
mass, or
size
Answer:
mass
Explanation:
The triple beam balance is an instrument used to measure mass very precisely.
why ammonium is not a molecular ion
Answer:
See below
Explanation:
Ammonium [tex](NH_{4}^+)[/tex] is not a molecular ion because it is just a poly-atomic ion. A molecular ion has a "negative or positive charge" as a whole but the positive charge on here is not on the whole. So, it is a poly-atomic ion and not molecular ion.
How many electrons can the n = 4 shell hold? 8 16 32 64
Answer:
32Explanation
n = 4
Now,let's find the number of electrons:
[tex]2 {n}^{2} [/tex]
plug the value
[tex] = 2 \times {4}^{2} [/tex]
Evaluate the power
[tex] = 2 \times 16[/tex]
Multiply the numbers
[tex] = 32[/tex]
Hope this helps...
best regards
Electrons are the sub-particles present in atomic shells. The (Principal Quantum Number) n = 4 shell of the atom can hold 32 electrons in it. Thus, option c is correct.
What is Principal Quantum Number?Principal Quantum Number (n) is defined as the distance of the electron from the nucleus and its energy in the atom. It can also be said to know the position of the electron in the energy level along with the orbital size.
The Principle Quantum Number, n = 4 depicts the fourth shell or energy level of the atom that can hold a specific number of electrons in it.
The electrons present in the shell or the energy level are determined by,
2n²
Here, n = 4
Substituting the values above,
= 2 (4)²
= 2 (16)
= 32
Therefore, the n = 4 energy shell can contain 32 electrons.
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The electron configurations of two unknown elements x and y are shown. X: 1s2 2s2 2p6 Y: 1s2 2s2 2p6 3s2 3p6 Which statement is most likely correct about the two elements? A) They will react because X can give up two electrons B) They will react because X and Y can share two pairs of electrons to become stable C) They will not react because both have a complete outermost shell and are stable D) They will not react because both will give up one electron. to become stable.
Answer:
B) They will react because X and Y can share two pairs of electrons to become stable
Explanation:
The electron configurations of two elements x and y are given :
X: 1s2 2s2 2p6
Y: 1s2 2s2 2p6 3s2 3p6
The statement that is true for both the elements is that, they both will react as they both can share two pairs of electrons to become stable.
To become stable the outermost shell or p orbital should have 8 electrons, so element X can gain 2 atoms to become stable.
Element Y can also react as it can also share two atoms to fulfill its 3p orbital and will stable.
Hence, the correct option is "B".
Two samples of sodium chloride were decomposed into their constituent elements. One sample produced 2.84 g of sodium and 4.37 g of chlorine. Which of the following could be the results of the decomposition of the other sample, being consistent with the law of constant composition (also called the law of definite proportions or law of definite composition)?
a) 4.17 g of sodium and 3.75 g of chlorine
b) 4.17 g of sodium and 6.42 g of chlorine
c) 4.17 g of sodium and 1.05 g of chlorine
d) 4.17 g of sodium and 12.1 g of chlorine
Answer:
The correct answer is b) 4.17 g of sodium and 6.42 g of chlorine
Explanation:
According to the law of definite proportions a chemical compound is composed always by the same elements in the same proportions by mass. In this case, the proportion of the elements by mass will be 4.37 g of chlorine (Cl) per 2.84 g of sodium (Na):
4.37 Cl/2.84 g Na= 1.54
We can calculate the proportions of the results in order to see which is the correct:
a) 3.75 g Cl/4.17 g Na = 0.899
b) 6.42 g Cl/4.17 g Na = 1.539 ⇒ ≅1.54
c) 1.05 g Cl/4.17 g Na = 3.971
d) 12.1 g Cl/4.17 g Na = 2.901
The option in which the proportion Cl/Na is equal to 1.54 is option b
In heating and melting curves, what is the name of the heat associated with the solid-liquid phase? A. Heat of formation B. Heat of fusion C. Heat of sublimation D. Heat of vaporization
Answer:
C I believe not quite sure tho
In heating and melting curves, the name of the heat associated with the solid-liquid phase is Heat of fusion.
What is the Heat of fusion ?
The standard fusion enthalpy is the amount of thermal energy required for a single mole of a substance to change states from a solid to a liquid or vice versa is known as the heat of fusion or specific melting heat. The melting point is the temperature at which it takes place, and it is also known as the latent heat of fusion or the enthalpy change of fusion.The temperature of a liquid or solid goes down when thermal energy is taken away. The temperature rises when heat and energy are added. However, additional energy—the heat of fusion—is required at the melting point—the transition point between solid and liquid. The molecules of a substance need to become more organized in order to change from liquid to solid. They require the withdrawal of additional heat in order to maintain their solid state. In the opposite direction, additional heat is required to induce the disorder from the solid crystal to the liquid.The temperature of water as it freezes can be measured to observe the heat of fusion. When you place a closed container of room temperature water in a very cold environment, say 20 °C, the temperature will gradually fall until it is just below the freezing point. After that, the temperature rises and stays the same as the water crystallizes. The temperature will again fall steadily after it has completely frozen.The heat of fusion causes the temperature to stop falling at (or just below) the freezing point. Before the temperature can continue to fall, the energy from the heat of fusion must be removed—the liquid must transform into a solid.
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A container initially holds 5.67 x 10^10-2 mol of propane and has a volume of V1. The volume of the container was increased by adding an additional 2.95 x 10^-2 mol of propane to the container, so that the container has a final volume of 1.93 L. If the temperature and pressure are constant, what was the initial volume of the container ,V1?
Answer:
The initial volume of the container was 1.27L
Explanation:
Avogadro's law states that under the same pressure and temperature, equal moles of gases occupies equal volume. The equation is:
V₁n₂ = V₂n₁
Where V is volume and n moles of 1, initial state and 2, final state.
In the problem, initial moles are 5.67x10⁻², final moles after the addition are:
5.67x10⁻² + 2.95x10⁻² = 8.62x10⁻² moles
And, after the addition, the volume is 1.93L.
Replacing in Avogadro's law:
V₁×8.62x10⁻² moles = 1.93L×5.67x10⁻² moles
V₁ = 1.27L
The initial volume of the container was 1.27LHow did Bohr describe the arrangement of particles within an atom?
A. Protons and electrons form the nucleus, with neutrons
orbiting it.
O B. Neutrons make up the atom's nucleus, with electrons and
protons orbiting it.
c. Protons make up the atom's nucleus, with electrons and
neutrons orbiting it.
O D. Protons and neutrons form the nucleus of the atom, with
electrons orbiting it.
Bohr describe the arrangement of particles within an atom by: O D. Protons and neutrons form the nucleus of the atom, with electrons orbiting it.
Who is Niels Bohr?This hypothesis states that the atom's core is a small, compact, positively charged nucleus. Protons which have a positive charge and neutrons which are neutral are both found in the nucleus.
Specific energy levels or electron shells are where the negatively charged electrons orbit the nucleus. Due to the quantization of these energy levels, only a limited number of discrete energy states are accessible to electrons.
Therefore the correct option is D.
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Who is john Dalton ?
Answer:
He is a English chemist physicist and meteorologist. He is best known for the atomic theory
Answer:
John Dalton was a scientist.
Explanation:
sodium has 11 protons 12 neutrons. what is the isotope nation
Answer:
these are two atoms which have the same number of protons but different number of neutrons
Explain how temperature and volume of a gas are related and use that to make a prediction about
how you can use this information to calculate absolute zero.
Answer:
See explanation
Explanation:
Charles law gives the relationship between volume and temperature of a gas. Charles law States that, the volume of a given mass of gas is directly proportional to its temperature at constant pressure.
Theoretically, it is assumed that when the absolute zero temperature has been achieved, the volume of any ideal gas will be found to be equal to zero. If the volume of the gas is zero, it now implies that all molecular motion will be stopped. This does not happen in real gases as all gases are found to condense to solids or liquids when this temperature is exceeded.
When volume is plotted against temperature, volume of the gas approaches zero at t = −273.15 °C, which is the x-intercept of the Charles law graph. Below this temperature, we can only get negative values of volume which does not exist hence, −273.15 °C is the lowest attainable temperature also known as the absolute zero.
Seawater is highly saline, which means it contains large amounts of dissolved salt. When seawater freezes and icebergs form, the water in the iceberg doesn’t take the salt with it. What effect will this phenomenon have on the concentration of salt in the water around the iceberg?
Answer:
Because the amount of liquid water decreases and the amount of dissolved salt remains constant, the concentration of salt in the liquid water around the iceberg will increase.
Explanation:
Answer:
Because the amount of liquid water decreases and the amount of dissolved salt remains constant, the concentration of salt in the liquid water around the iceberg will increase.
Explanation:
PLATO exact answer
pls help...
You are a forensic scientist working on a murder case. You have taken the blood sample from the crime scene and put it through Electrophoresis and Southern blotting. What step do you need to take next? A. Add ethanol B. Add restriction enzymes C. Add minisatellites D. Add radioactive probes
Add minisatellites. Hence, option C is correct.
What is Electrophoresis?Electrophoresis is a laboratory technique used to separate DNA, RNA or protein molecules based on their size and electrical charge.
You are a forensic scientist working on a murder case. You have taken the blood sample from the crime scene and put it through Electrophoresis and Southern blotting. you need to add minisatellites.
Hence, option C is correct.
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what are the property of electrons
Answer:
basically an atom consist of electons and protrons .
electrons have a negative charge and in a circut the charge of electorns is more.
Answer:
listed below.
Explanation:
Few properties of electrons include:
- Electrons are subatomic particles with an electric charge of -1.
- Electrons have mass of approximately 1/1836 that of the proton.
- Electrons revolve around the nucleus of the atom.
- Electrons spin around their own axis.
Match each term below with its definition or description.
1 The point in a titration when the added amount of standard reagent is equal to the amount of analyte being titrated.
2 The analyte is titrated with the standard reagent and the volume of standard solution required to complete the reaction is measured.
3 A reagent that is pure and stable, which can be used directly after weighing.
4 The analyte that is being analyzed in the titration.
5 Standard reagent is added in excess to ensure complete reaction with the analyte. The excess reagent is then titrated with a second standard reagent.
6 A solution, whose concentration is known, often made from a reagent of known purity.
7 The standard reagent of known concentration that is added from a buret to the analyte solution.
8 The analyte does not react directly with the titrant so it is converted to another form which will react with the titrant.
9 The point in a titration when a change in the analyte solution is observed, indicating equivalency.
10 It is added to the analyte solution and aids in the observation of the completion of the reaction.
a) End Point
b) Indicator
c) Direct Titration
d) Back Titration
e) Indirect Titration
f) Primary Standard
g) Standard Solution
h) Titrand
i) Equivalence Point
j) Titrant
Answer:
1. Equivalence point
2. Direct titration
3. Primary standard
4. Titrand
5. Back titration
6. Standard solution
7. Titrant
8. Indirect titration
9. End point
10. Indicator
Explanation:
1. The equivalence point is the tiration point at which the quantity or moles of the added titrant is sufficient or equal to the quantity or moles of the analyte for the neutralization of the solution of the analyte.
2. Direct titration is a method of quantitatively determining the contents of a substance
3. A primary standard is an easily weigh-able representative of the mount of moles contained in a substance
4. A titrand is the substance of unknown concentration which is to be determined
5. The titration method that uses a given amount of an excess reagent to determine the concentration of an analyte is known as back titration
6. A standard solution is a solution of accurately known concentration
7. A titrant is a solution that has a known concentration and which is titrated unto another solution to determine the concentration of the second solution
8. Indirect titration is the process of performing a titration in athe reverse order
9. The end point is the point at which the indicator indicates that the equivalent quantities of the reagents required for a complete reaction has been added
10 An indicator is a compound used to visually determine the pH of a solution.
The titration has been the neutralization reaction in which the titrand and the titrant react to form the salt and the water and help in the determination of the qualitative and quantitative properties.
What is an Endpoint?In a titration reaction, the endpoint has been the point at which the equivalent amount of reagent has been completely neutralized.The Indicator has been the chemical that changes to indicate the endpoint of the reaction.Direct titration involves the reaction for the quantitative determination of the substances.The back titration can be given as the reaction in which the excess reagent is used to titrate the second standard reagent in the reaction.Indirect titration can be given as the reaction of the analyte to convert to another form and then the analysis with the titrant.The primary standard has been the known concentration of the pure and stable weighing reagent.The standard solution has been the solution of the known concentration in the reaction.Titrand has been the unknown sample that has to be analyzed.The equivalence point is the concentration point at which the quantity of titrant added to the titrand has been equal.Titrant has been the known concentration of sample that has been added to equivalent the unknown sample.Learn more about titration here:
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The radioactive isotope used for carbon dating is
1. Carbon 12
2. Carbon 13
3. Carbon 15
4. Carbon 14
Carbon 14 would be your answer, however if it's more than one answer it would also be Carbon 12, so yeah. Your best bet would be Carbon 14.
True or False a. Sodium chloride is the main salt found in sea water. ……………………………………………………………………. b. Potassium bromide salt is not found in sea water ……………………………………………………………………. c. Both evaporation and electric conduction techniques prove that sea water contain the dissolved salts. …………………………………………………………………….. d. The amount of fresh water is greater than 5% of the total Earth water. …………………………………………………………………….. e. In water treatment process, filter membrane is used to remove fine particles and other impurities from water. …………………………………………………………………………....
Answer:
A is true NaCl
B is false K2Br
C is true
D false its only 0.03 percent
E is true