It will take 56 days to go from 100% iodine-131 to less than 1% iodine-131.
From the table, we can see that the half life of iodine-131 is 8 days. We can see that it takes 8 days to have 50% of iodine-131
After 16 days, we will have 25 % of iodine-131
After 24 days, we will have 12.5 % of iodine-131
After 32 days, we will have 6.25% of iodine-131
After 40 days, we will have 3.125% of iodine-131
After 48 days, we will have 1.5625% of iodine-131
After 56 days, we will have 0.78125% of iodine-131
After 56 days, the percentage of iodine-131 drops to less than 1%.
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PLEASE HELP!!!!! WILL GIVE BRAINLIEST!!!!
The answer should be A
VisibleVisible wave length visible wavelength of light that are emitted by Adams can be used to get Nate explosive devices remotely
what mass of water (in grams) is produced by the reaction of 23.0 g of SiO2?
The mass of water produced by the reaction of the 23 g of [tex]SiO_2[/tex] is 13.8 g.
The given chemical reaction;
[tex]4Hf (g) \ + \ SiO_2 (s) \ --> \ SiF_4(g) \ + \ 2H_2O(l)[/tex]
In the given compound above, we can deduce the following;
molecular mass of [tex]SiO_2[/tex] = 28 + (2 x 16) = 60 gmolecular mass of [tex]2H_2O[/tex] = 2(18) = 36 g60 g of [tex]SiO_2[/tex] --------- 36 g of water
23 g of [tex]SiO_2[/tex] ------------- ? of water
[tex]mass \ of \ water = \frac{23 \times 36}{60} = 13.8 \ g \ of \ water[/tex]
Thus, the mass of water produced by the reaction of the 23 g of [tex]SiO_2[/tex] is 13.8 g.
"Your question is not complete, it seems to be missing the following information";In the reaction of the given compound, [tex]4Hf (g) \ + \ SiO_2 (s) \ --> \ SiF_4(g) \ + \ 2H_2O(l)[/tex], what mass of water (in grams) is produced by the reaction of 23.0 g of SiO2?
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A total solar eclipse occurs because the moon can totally block the sun. If the moon was smaller or farther from earth, a total eclipse
Could occur
Could not occur
Answer:
both
Explanation:
id say that it could occur but also not as much. the moon would be smaller and further from the earth to where we would barely be able to see it. if the full moon is barely visible then im sure the total solar eclipse wouldn't be as noticeable as it is now. but thats just my opinion
Is the molecule H2+ stable?
Answer: yes it is
Explanation:Bond order
The antibonding orbital is empty. Thus, H2 is a stable molecule
Which describes a chemical change? (Select all that apply.)
A new substance is created.
A phase change is occurring.
It is a permanent change.
It can be a physical change.
Explanation:
it is a permanent change
Answer: It is a permenat change
Explanation: Because you are creating it into something else and when it turns into that thing it stays like that permanatly.
5 examples of Earth Surface .
Answer:
lithosphere (land)
hydrosphere (water)
biosphere (living things)
atmosphere (air).
[EASY][50pt] Temperature vs Time Graph
5. In what state of matter does this substance exist at the 22 minute mark?
6.At what temperature does condensation occur?
7.What phase change occurs at 70C
#5
At 22min the temperature is at 40°C
So the matter is at solid state.#6
Graph ended at 20°C so condetion occured at 20°C
#7
After 70°C the matter got melted do its at liquid state
1. What is the shape of an organic molecule containing a triple bond with respect to the carbons on either side of the bond?
Explain your answer
Answer:
The alkyne is linear
Explanation:
Any molecule with a triple bond is considered an alkyne. In regards to the shape, because carbon can only bond to 4 different atoms at once a triple bond fills in 3 of the required 4 atoms needed to reach the molecules ground state (when it's most stable). The more electrons shared between atoms, the shorter the bond will be which results in a stronger and more linear line. Keep in mind a quadruple bond is not possible between carbons as of now.
What method would you use to separate sand from gasoline?
Answer:
Filtration (The process of separating liquids and solids)
Explanation:
Filtration works best when the solute isn't dissolved in the solvent. Basically like how you can filter dirt or sand from water. The opposite of this would be if water and sugar where mixed together you cannot unmix this duo with filtration but with the example given you can use the process of filtration to rid the gasoline of sand.
what happens when co2 dissolves in water
Determine the molar solubility for Cr(OH)3 Ksp = 6.3x10^-31 ....
a) Set up the ICE table Cr(OH)3 (s) <-> Cr^3+ (aq) + 3OH^- (aq)
b) Ksp expression
c) Determine molar solubility
The equilibrium constant shows the extent of dissolution of a substance in solution. The molar solubility of the compound here is 1.2 * 10^-8 M.
What is solubility product?The solubility product is the equilibrium constant that shows the extent to which a substnace is dissolved in soution.
Now let us set up the ICE table as shown;
Cr(OH)3 (s) <-> Cr^3+ (aq) + 3OH^- (aq)
I 0 0
C +x +3x
E x 3x
Ksp = [Cr^3+] [OH^- ]^3
6.3x10^-31 = [x] [3x]^3
6.3x10^-31 = 27x^4
x = 4√6.3x10^-31 /27
x = 1.2 * 10^-8 M
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Calculate the concentrations of all species in a 0.100 M Na2CO3 solution.
The concentrations of all species in a 0.100 M Na₂CO₃ are:
1. The concentration of Na⁺ in the solution is 0.2 M.
2. The concentration of CO₃²¯ in the solution is 0.1 M
We'll begin by writing the dissociation equation for Na₂CO₃. This is illustrated below:
Na₂CO₃(aq) —> 2Na⁺(aq) + CO₃²¯(aq)
Thus, the species in Na₂CO₃ are Na⁺ and CO₃²¯
From the balanced equation above,
1 mole of Na₂CO₃ contains 2 moles Na⁺ and 1 mole of CO₃²¯
1. Determination of the concentration of Na⁺.
From the balanced equation above,
1 mole of Na₂CO₃ contains 2 moles Na⁺
Therefore,
0.100 M Na₂CO₃ will contains = 2 × 0.1 = 0.2 M Na⁺
Thus, the concentration of Na⁺ in the solution is 0.2 M.
2. Determination of the concentration of CO₃²¯
1 mole of Na₂CO₃ contains 1 mole of CO₃²¯
Therefore,
0.100 M Na₂CO₃ will also contains 0.100 M CO₃²¯
Thus, the concentration of CO₃²¯ in the solution is 0.1 M
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The Lewis electron-dot structure of oxygen has how many dots?
Answer:
Oxygen has 6 valence electrons and follows the octet rule.
If you were drawing a lewis structure for O2, there would be a total of 12 valence electrons (6 x 2 = 12).
The completed structure would have a double bond between the two oxygen atoms with 2 lone pairs per oxygen, giving you a total of 8 electrons that are lone pairs (or dots).
How many atoms of Xe does 7.84 moles of Xe contain?
A flask of water is sealed with a balloon and heated to various temperatures on a hot plate
Answer:
What is the question?
Explanation:
You just gave a statement.
Answer:
it will increase
Explanation:
Calculate AH for the following reaction:
-
-
2NO2(g) → N204(9)
Use appropriate data from the following listing:
NO(g) + NO2(g) + O2(g) → N2O5(9) ΔΗ, = -113.7
NO(g) + NO2(g) → N2O3(g)
9
AH2 = -36.1
N205(9) ► N,05(s)
,
AH = -55.3
N2O3(g) + N2O3(s) -→ 2N204(9)
ΔΗ, = -8.100
2NO(g) + O2(g) → 2NO2(g)
ΔΗς = -112
Answer:
Explanation:
Explain why the element of an atom doesn't change if you remove or add electrons or neutrons
Answer: Does not change.
Explanation:
The atomic number and the electrical charge of that atom would remain unchanged. Neutrons do not carry an electrical charge so adding or removing them from the nucleus does not change the electrical charge of the nucleus.
What will happen to the pH of sodium bicarbonate if vinegar is added to it?
Answer:
The overall chemical reaction between baking soda (sodium bicarbonate) and vinegar (weak acetic acid) is one mole of solid sodium bicarbonate reacts with one mole of liquid acetic acid to produce one mole each of carbon dioxide gas, liquid water, sodium ions, and acetate ions. The reaction proceeds in two steps
Write the full electron configuration for a Ca+ ion.
Answer:
[Ar] 4s²
Explanation:
The full electron configuration for the Ca+ ion is:
1s² 2s² 2p⁶ 3s² 3p⁶.
How to determine the electron configuration for the Ca+ ionTo determine the full electron configuration for a Ca+ ion, we need to remove one electron from the neutral calcium atom (Ca). The neutral calcium atom has the electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s².
When Ca loses one electron to form the Ca+ ion, the electron removed comes from the highest energy level, which is the 4s orbital.
Therefore, the full electron configuration for the Ca+ ion is:
1s² 2s² 2p⁶ 3s² 3p⁶.
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Which characteristic do valence electrons indicate about reactions between atoms? (1 point)
o electronegativity difference
o absolute electronegativity
o bond type
o bond number
The characteristic of reactions that depends on valence electrons is the bond type.
In chemistry, a chemical bond could be;
IonicCovalentThe type of bond formed depends on the number of valence electrons present. When there are few valence electrons on an atom, it mostly forms ionic bonds.
When there are more electrons on an atoms, it mostly forms covalent bonds and the electrons between the atoms are shared.
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Answer:
D: bond number
the class of organic compound below contains a carbonyl group as a part of its structure?
Aldehydes and Ketones. Aldehydes and ketones are classes of organic compounds that contain a carbonyl (C=O) group.
that's the correct answer
can I get brainilest
What is condensation
1. Oxygen was discovered by Joseph Priestley in 1774 when he heated mercury (II) oxide, HgO, to decompose it to form its constituent elements. How many moles of mercury (II) oxide are needed to produce 125 g of oxygen?
Given:
Unknown:
Mole ratio:
Solution:
2. In a blast furnace, iron (III) oxide is used to produce iron by the following (unbalanced) reaction:
Fe2O3(s) + CO(g) Fe(s) + CO2(g)
If 4000 g of Fe2O3 is available to react, how many moles of CO are needed?
Given:
Unknown:
Mole ratio:
Solution:
Final answer:
ugh pls help:(
Answer:
1. 7.81 moles HgO
2. n = mass/molar mass = (4000 g)/(159.69 g/mol) = 25.05 mol.
Explanation:
How many moles of mercury (II) oxide are needed to produce 125 g of oxygen?
2HgO ==> 2Hg + O2
125 g O2 x 1 mol O2/32 g x 2 mol HgO / mol O2 = 7.81 moles HgO
------------------------------------------------------------------------------------------------------------
If 4000 g of Fe2O3 is available to react, how many moles of CO are needed?
The no. of moles of CO are needed = 75.15 mol.
Fe₂O₃ + 3CO → 2Fe + 3CO₂,
It is clear that 1 mol of Fe₂O₃ reacts with 3 mol of CO to produce 2 mol of Fe and 3 mol of CO₂.
If 4.00 kg Fe₂O₃ are available to react, how many moles of CO are needed?
We need to calculate the no. of moles of 4.00 kg Fe₂O₃:
n = mass/molar mass = (4000 g)/(159.69 g/mol) = 25.05 mol.
Using cross multiplication:
1 mol of Fe₂O₃ need → 3 mol of CO to react completely, from stichiometry.
25.05 mol of Fe₂O₃ need → ??? mol of CO to react completely.
The no. of moles of CO are needed = (3 mol)(25.05 mol)/(1 mol) = 75.15 mol.
define the term chemotherapy.
I'm not able to understand that what is written in the pic.. As I can't understand this language..
Treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Chemotherapy may be given by mouth, injection, or infusion, or on the skin, depending on the type and stage of the cancer being treated.
96 POINTS
1. An atom of platinum has a mass number of 195 and an atomic number of 78. How many protons and neutrons are in this atom? – Calculate your answer and please note that work must be shown to earn credit.
neutrons=117
protons=78
Answer:
Platinum has mass number 195.
The atomic number of platinum =78
so the number of protons is 78.
By using simple formulas
we can find out that how many neutrons and protons are present in an atom of platinum-195.
Mass number = neutrons + protons
195=neutrons + 78
neutrons=195-78=117
so the number of neutrons is 117.
Describe how you could show by adding aqueous sodium hydroxide and aqueous ammonia that a solution contained zinc ions.
Answer:
Learning Task 3. Solving word problems involving multiplication of deci-
the
A cstep in solving word problems. Do these in your notebook. ),
1. A clerk is paid P 45.25 per hour for 40 hours a week, 1.50 times the
regular rate for overtime and double the rate for a holiday. How much
holiday?
2. fofkmputer programmer earns a regular hourly rate of P50.00. If he
worked 42.75 hours in a week, how much did he earn?
3. Arthur earns P1350.00 a day. He sets aside 0.10 of this for savings.
How much does he save in a month?
4. Mr. Fernandez has a monthly pay of P 5,450. The tax deducted from
year?
5. Dianne works 2.5 hours a day from Monday to Friday and 3.75 hours
his a
on Saturday. If he is paid P25.00 per hour, how much does he earn in
a
week?
Explanation:
Learning Task 3. Solving word problems involving multiplication of deci-
the
A cstep in solving word problems. Do these in your notebook. ),
1. A clerk is paid P 45.25 per hour for 40 hours a week, 1.50 times the
regular rate for overtime and double the rate for a holiday. How much
holiday?
2. fofkmputer programmer earns a regular hourly rate of P50.00. If he
worked 42.75 hours in a week, how much did he earn?
3. Arthur earns P1350.00 a day. He sets aside 0.10 of this for savings.
How much does he save in a month?
4. Mr. Fernandez has a monthly pay of P 5,450. The tax deducted from
year?
5. Dianne works 2.5 hours a day from Monday to Friday and 3.75 hours
his a
on Saturday. If he is paid P25.00 per hour, how much does he earn in
a
week?
How many moles are in 29.5 grams of Ax?
A. 1.3 moles
B. 1.8 moles
C. 0.78 moles
D. 678 moles
The number of moles present in 29.5 grams of argon is 0.74 mole.
The atomic mass of argon is given as;
Ar = 39.95 g/mole
The number of moles present in 29.5 grams of argon is calculated as follows;
39.95 g ------------------------------- 1 mole
29.5 g ------------------------------ ?
[tex]= \frac{29.5}{39.95} \\\\= 0.74 \ mole[/tex]
Thus, the number of moles present in 29.5 grams of argon is 0.74 mole.
"Your question seems to be missing the correct symbol for the element"
Argon = Ar
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how many gallons in one cubic foot?
Answer:
1cf gallon=7.481 us liquid gallon
Describe how you could show by adding aqueous sodium hydroxide and aqueous ammonia that a solution contained zinc ions.
Result with sodium hydroxide
Excess sodium hydroxide
Result with aqueous ammonia
Excess aqueous ammonia
Answer:
*result with sodium hydroxide: white ppt of Zn(OH)2
*excess sodium hydroxide: Precipitate dissolves to form a COLOURLESS solution
*Result with Aqueous ammonia: White ppt of Zn(OH)2
*excess aqueous ammonia: Precipitate dissolves to form a COLOURLESS solution
What are acids ? Will they harm skin
Hydrochloric acid can cause damage if it comes into contact with your lungs, eyes, stomach, or skin. If hydrochloric acid comes into contact with your skin, it can cause: chemical burns. scarring.