First, let's recall the equation for half-life:
N(t) = [tex]N_{0}[/tex] · [tex]\frac{1}{2}^{\frac{t}{t_{1/2}}}[/tex]
Woah.
While we could certainly solve this question by using the half-life equation, it might be easier to just give this question some thought.
Half-life, is, essentially, the time it takes for radioactive material to be halved. For example, if something had a half-life of ten years and weighed 20 pounds, after ten years it would weigh 10 pounds and after another ten years would weigh 5 pounds, then 2.5, and so on. (Note that it never actually reaches 0! It keeps halving and halving over and over again, becoming smaller and smaller but never disappearing!)
In this question, we're given the half-life of Carbon-14 and asked how old a tree with 1/4 the amount of carbon-14 of a normal tree would be. Let's think about this question:
We can make the assumption that a "modern" tree is a tree that is 0 years old. Why? Well, it would make it painfully complicated if we assumed anything other than that, and your chemistry teacher wouldn't be that cruel (I hope).How many half-lives must the Carbon-14 go through for the amount to be 1/4? Since the amount halves every half-life, we can count on our fingers - one half-life will make the amount 1/2 the original, two half-lives will make the amount half the 1/2 amount, making it 1/4 the amount... hey! We got it!We figured out that it takes two half-lives for Carbon-14 to be 1/4 its original amount! Since the duration of a half-life never changes, we can simply multiply 5730 by 2 to find how many years it'd take to achieve two half-lives:
5730 · 2 = 11460
The tree is about 11,460 years old.
And we've solved it! (A quick tip - if you ever encounter a question like this again, you can quickly calculate the number of half-lives in your head depending on the amount remaining that they give you. Just keep halving the amount every half-life! One half-life is 1/2, two half-lives is 1/4, three is 1/8, four is 1/16, and so on and so forth)
If you have any questions about anything I explained here or need clarification on anything, just let me know! Good luck!
- breezyツ
Carbon dioxide has a relatively high solubility in blood plasma, although it has a very low partial pressure. What law describes this phenomenon
Answer:
The bulk of carbon dioxide is carried chemically combined with the amino acids of hemoglobin as carbaminohemoglobin in the RBCs.
2N₂ + 5 0₂2 N₂O5 What mass of nitrogen is required to react with 5.04 grams of oxygen?
Answer:
1.76g of N
Explanation:
5.04g x 1mol/16mol x 2mol/5mol x 14.01g/1mol = 1.76g
How many energy levels does europium have?
Answer:
6 Energy levels
Explanation:
First Energy Level: 2
Second Energy Level: 8
Third Energy Level: 18
Fourth Energy Level: 25
Fifth Energy Level: 8
Sixth Energy Level: 2
Hope this helps.
2. During which of the following stato changes would the particles in the matter become more spread out?
changing from liquid to gas?
changing from gas to liquid?
changing from gas to solid?
Answer
changing from liquid to gas
Explanation
changing from liquid to gas
One year, a herd of cattle released 2.44 metric tons of CH4 (methane) into the atmosphere. How many metric tons of carbon did this methane contain
The mass, in metric tons, of carbon in the methane is 1.83 metric tons
Calculating mass in a substance
From the question, we are to determine the quantity of carbon in the methane
The mass of carbon in the methane can be calculated from
Mass of carbon in the methane = [tex]\frac{Mass\ of\ carbon\ in\ a\ molecule\ of \ methane}{Mass\ of\ a\ molecule\ of \ methane}\times Total\ mass\ of\ the\ methane[/tex]
Mass of carbon in a molecule of methane = 12 g
Mass of a molecule of methane = 16 g
Therefore,
Mass of carbon in the methane = [tex]\frac{12}{16} \times 2.44[/tex]
Mass of carbon in the methane = 1.83 metric tons
Hence, the mass, in metric tons, of carbon in the methane is 1.83 metric tons
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At a research lab, a scientist carelessly pours cultures of living microbes down the drain
Answer:
that's not good
Explanation:
microbes???? not good for a sewage system
Using one specific example, explain why the human genome project
considered important.
Answer:
initiated the comprehensive discovery and cataloguing of a 'parts list' of most human genes
Explanation:
If right you will be marked brainiest :)
Answer: They are the same species and have the same traits.
Explanation: These horses are well, the same species because they are horses. They have very similar traits.
Let me know if this is right!
Why is the? The second ionization energy of sodium is about three times greater than the second ionization energy of magnesium
Answer:
~Na+1 is already in the preferred form. Because of this, the second ionization energy of sodium is higher than normal. Mg+1 loses an electron to form s2 p6 .
A 50 mL sample is held at 100 kPa. What pressure does it exert when the gas is compressed to 40 L.
Who's Law did you use?
Newton's third law
Explanation:
The chemical equation below shows the combustion of methane (ch4). ch4 2o2 right arrow. co2 2h2o the molar mass of oxygen gas (o2) is 32.00 g/mol. the molar mass of carbon dioxide (co2) is 44.01 g/mol. what mass of co2, in grams, will form when 8.94 g o2 completely react? 3.25 grams 6.15 grams 13.0 grams 53.0 grams
6.15 grams of carbon dioxide is form when 8.94 g of oxygen is completely react.
How we calculate mass from moles?Mass of any substance will be calculated from moles as :
n = W/M, where
W = required mass
M = molar mass
Given combustion reaction is:
CH₄ + 2O₂ → CO₂ + 2H₂O
Given mass of O₂ = 8.94 g
Molar mass of O₂ = 32.00 g/mole
Moles of O₂ = 8.94 / 32 = 0.279 mole
From the stoichiometry of the reaction, it is clear that:
2 moles of O₂ = produce 1 mole of CO₂
0.279 moles of O₂ = produce 1/2×0.279 = 0.139 moles of CO₂
Molar mass of CO₂ = 44 g/mole
Required mass of CO₂ will be calculated as:
W = n × M
W = 0.139 × 44 = 6.15 grams
Hence, option (2) is correct i.e. 6.15 grams.
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Answer:
Option 2/ B. 6.15 grams on edge.
Explanation:
S/o to the person above me, got it because of them.
During a lab, 1.62g of COCl2 · x H2O were heated. After heating, only 0.88g of COCl2 remained. Calculate the formula of the hydrate.
Show your work.
You have to break down the cobalt chloride and water by finding the mass of each and using empirical formula.
Answer:
Explanation:
Let the number of moles of water in the required formula be "y".
The final formula should be in the form of : CoCl2 yH2O
1.62 g is the weight of CoCl2 and water in the sample
After heating, the remaining mass represents the mass the salt only
mass of water in sample = 1.62 - 0.88 = 0.74 g
From the periodic table:
molar mass of cobalt is 59 g
molar mass of chlorine is 35.5
molar mass of hydrogen is 1
molar mass of oxygen is 16
molar mass of formula = 59 + 2(35.5) + 18y = 130 + 18y g
Now we have calculate the mass/molar mass for each part of the formula (salt and water) and equate them to get number of moles of water as follows:
0.88 / 130 = 0.74 / y18
y = 6.07 which is approximately 6 moles
Thus, the final formula is CoCl2 6H2O. This hydrate is called cobalt(II)chloride hexahydrate.
give brainliest.
(c) Graphite is another naturally-occurring form of carbon.
Graphite can be used in pencils because it is soft and can leave marks on paper.
Graphite can also be used as a conductor of electricity.
Explain why graphite is soft and conducts electricity.
Refer to structure and bonding in your answer.
(5)
DO NOT WRITE IN THIS AREA
Graphite is a fantastic lubricant and a powerful electrical conductor because of these unbound electrons.
What is the purpose of Unbound?Unbound can serve as a caching server, it can also perform recursion, store records obtained from other DNS servers, and provide an authoritative service, such as if you only have a few zones.
As a result, it can act as a "glue" server or host a small zone with only a few domains, making it ideal for a lab.
Why need to utilize Unbound DNS?
With its harden-glue, access control, maximum randomization for request ID and ports, response scrubbing, case preservation, plus Denial of Service or DoS prevention capabilities, Unbound is feature-rich with DNS Security. These are only a few.
Therefore, graphite is a fantastic lubricant and a powerful electrical conductor because of these unbound electrons.
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#SPJ1
Burning hydrogen is an example of a chemical reaction. The reaction is
shown in the diagram. Which of the following statements about energy in
this reaction is the most accurate?
Answer:
Energy is first released then arbsorbed the eventually it dissappears
Explanation:
Which do you think will cool the fastest?
sand
water
air
metal
Examine the picture above. What process does it represent?
Answer:
The formation of water from hydrogen and oxygen
Explanation:
Will give brainliest... what is the [OH-] of a solution whose pOH is equal to 2.86
Answer:
the pOH of a solution is the negative logarithm of the hydroxide-ion concentration. by this yields a [OH − ] of 1.0 × 10 -10 M. Finally the pOH of the solution equals -log(1.0 × 10 -10 ) = 10.Explanation:
The concentration of hydroxide ion of a solution whose pOH value is equal to 2.86 is 1.38×10⁻³ M.
How do we calculate the concentration of OH⁻?Concentration of hydroxide ion will be calculated by using the pOH value by using the below equation as:
pOH = -log[OH⁻]
[OH⁻] = [tex]10^{-pOH}[/tex]
Given that value of pOH = 2.86
On putting values we get,
[OH⁻] = [tex]10^{-2.86}[/tex]
[OH⁻] = 0.00138 = 1.38×10⁻³ M
Hence concentration of hydroxide ion is 1.38×10⁻³ M.
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what mass of magnesium bromide is produced when 35cm3 of 0.18 mol/dm3 of hydrogen bromide is treated with magnesium nitrate?
Answer:
C3H8
Explanation:
1 1.5mol
2 0.75mol
3 0.667mol
Questions 1.2
1 16.7mol
2 8.3×10−3mol
Questions 1.3
1 9
2 11
3 12
4 24
5 22
Questions 1.4
1 a) 151.9
b) 162.1
c) 60.0
d) 132.1
e) 388.8
2 a) 0.5mol
b) 2.5mol
c) 0.6mol
d) 2.0mol
e) 0.38mol
3 a) 180.6g
b) 44.46g
Questions 1.5
1 Mr = 277.9 moles of oxygen = 11
2 Mr = 474.3 moles of oxygen = 20
Questions 1.6
1 Cu2S
2 C3H8
3 CaFe2O4
Questions 1.7
1 a) 2H2 + O2 → 2H2O
b) I2 + 3Cl2 → 2ICl3
c) NaOH + Al(OH)3 → NaAlO2 + 2H2O
d) 2H2S + SO2 → 3S + 2H2O
e) 4NH3 + 3O2 → 2N2 + 6H2O
2 a) MgCO3 → MgO + CO2
b) Pb(s) + 2AgNO3(aq) → Pb(NO3)2(aq) + 2Ag(s)
c) Na2O(s) + H2O(l) → 2NaOH(aq)
d) 2FeCl2 + Cl2 → 2FeCl3
e) Fe2(SO4)3 + 6NaOH → 2Fe(OH)3 + 3Na2SO4
Questions 1.8
1 17.0g
2 60.7g
3 51.1%
Questions 1.9
1 1.2dm3
2 Volume of SO2 = 50cm3; mass of sulfur = 0.20g
Questions 1.10
1 a) 2.67moldm−3
b) 0.025moldm−3
c) 0.833moldm−3
2 a) 0.75mol
b) 0.044mol
c) 0.010mol
true or false: A person standing still with two heavy bundles is doing a lot of work
Which explanations did you include in your response? Check all that apply. The oxidation number of carbon changes from -1 to +4. The oxidation number of oxygen changes from 0 to -2. Carbon is oxidized. Oxygen is reduced. Electrons are transferred from carbon to oxygen.
Answer:
B, E
Explanation:
Edge
explain the occurrence of oxygen
Answer:
Oxygen is one of the most abundant elements on Earth. Oxygen accounts for 20.9% of the atmosphere, 45% of the Earth's crust (as oxide minerals) and also accounts for almost all of the mass of water on Earth (89%). It is found in a huge number of natural minerals including sulfates, phosphates, carbonates and oxides.
Explanation:
Hope this helps
Convert 30.0g of water to moles
please help
Answer:
1.7
Explanation:
1 grams Water to mol = 0.05551 mol
30 grams Water to mol = 1.66525 mol
if we round that up the answer is 1.7
Aluminum metal can be recycled from scrap metal by melting the metal to evaporate impurities. a. Calculate the amount of heat needed to purify 1.00 mole of Al originally at 298 K by melting it. The melting point of Al is 933 K. The molar heat capacity of Al is 24 J/(mol K), and the heat of fusion of Al is 10.7 kJ/mol.
The amount of heat required to purify the Al is 25.94 * 10^3 J
What is heat capacity?The term heat capacity refers to the amount of heat required to raise the temperature of a substance by 1K. The aluminum was heated from 298 K to 933 K then it melted.
The total heat required is;
H = ncdT + nL
H = (1 * 24 * (933 - 298)) + (1 * 10.7 * 10^3)
H = 15.24 * 10^3 J + 10.7 * 10^3 J
H = 25.94 * 10^3 J
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Which choice describes climate? In March 1971, Canada was hit by a major blizzard and up to 32 inches of snow fell. The U.S. gulf coast was hit by Hurricane Katrina in 2005 and suffered extensive damage. The U.S. gulf coast typically has warm, wet weather and tropical storms during the summer and fall. An extremely dangerous tornado hit Jarrell, Texas in 1997 destroying 40 homes.
Answer:
Its C
Explanation:
If you look, you can see that it tells you the humidity and the that its warm but it also tells you that it storms a little to and that makes it easier to know the climate but if it just sayed it was warm that wouldn't be enough information
CAN I PLS HAVE BRAINLIEST. I NEVER GET IT. ITS A LITTLE CROWN UNDER MY ANSWER. PLS. ILL GIVE YOU BRAINLIEST JUST PLS
Where does Respiration mainly take place in?
A - Mitochondria
B - The nucleus
C - The cell wall
D - The vacuole
Write the name of the Formula, Chromium(III) Sulfide
Answer:
Cr2S3
Explanation : Cr is +3
S is - 2 so when balancing it will give Cr2S3
Somebody help me? my head hurts here
1.between which two points is the car accelerating at the greatest rate?
2.between which two points is the car travelling at a steady speed?
3.what is the acceleration of the car between C and D?
4.between which two points is the acceleration getting bigger and bigger?
5.what is the acceleration of the car between D and F?
Answer 1 :
[tex]\green{\sf{D \: and \: E}}[/tex]
Step-by-step explanation:
As per graph, the highest lines are D and E. They are increasing.
Answer 2:-
[tex]\sf{\blue{B \: and \: C}}[/tex]
Step-by-step Explanation:
It is because the line between B and C is straight, indicating that it is steady.
Answer 3:-
[tex]\sf{\pink{2 \: m/s}}[/tex]
Step-by-step Explanation:
Its because the interval between line CD can be taken as-
[tex]\sf{40-50 = 1 m/s} \\ \sf{50-60 = 2 m/s}[/tex]
Hence, 2 m/s.
Answer 4:
[tex]\sf{\red{A \: and \: E}}[/tex]
Step-by-step Explanation:
We can see from the graph that the change in lines us occurring between initial and final points, i.e., between A and E.
Answer 5:
[tex]\sf{\purple{1m/s}}[/tex]
Step-by-step Explanation:
This is because, we can consider the interval between points D and E as :-
[tex]\sf{60-70=1m/s}[/tex]
A 1.00 l volume of hcl reacted completely with 2.00 l of 1.50 m ca(oh)2 according to the balanced chemical equation below. 2hcl ca(oh)2 right arrow. cacl2 2h2o what was the molarity of the hcl solution? 0.375 m 1.50 m 3.00 m 6.00 m
6 M is the molarity of the HCl solution with volume 1 liter.
How we calculate molarity?
Molarity (M) of solution is define as the number of moles (n) of solute present in per liter (V) of solution, i.e. M = n/V.
Given chemical reaction is:
2HCl + Ca(OH)₂ → CaCl₂ + 2H₂O
Given volume of HCl = 1 L
Given volume of Ca(OH)₂ = 2 L
Molarity of Ca(OH)₂ = 1.50M
Moles of Ca(OH)₂ = 1.50 × 2 = 3 moles
From the stoichiometry of the reaction:
1 mole of Ca(OH)₂ = react with 2 moles of HCl
3 mole of Ca(OH)₂ = react with 2×3=6 moles of HCl
Molarity of HCl will be calculated by using the above given formula as:
M = 6/1 = 6M.
Hence, option (4) is correct i.e. 6 M.
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Answer:
D
Explanation:
trust
Type the correct answer in the box. Express your answer to three significant figures. Sodium hydroxide and magnesium chloride react as shown by this equation: 2NaOH MgCl2 → Mg(OH)2 2NaCl. Suppose the reaction begins with 637 milliliters of 1. 35 M sodium hydroxide solution and excess magnesium hydroxide. What is the theoretical yield of magnesium hydroxide if the resulting solution has a volume of 2. 82 liters? Use the periodic table and the polyatomic ion resource. The mass of magnesium hydroxide formed is grams.
25.07grams is the theoretical yield of magnesium hydroxide if the resulting solution has a volume of 2. 82 liters.
How we calculate the mass from moles?Mass of any substance will be calculated from moles as:
n = W/M, where
W = given or required mass
M = molar mass
Given chemical reaction is:
2NaOH + MgCl₂ → Mg(OH)₂ + 2NaCl
From the stoichiometry of the reaction, it is clear that:
2 moles of NaOH = produce 1 mole of Mg(OH)₂
1 mole of NaOH = produce 1/2 mole of Mg(OH)₂
Given concentration of NaOH = 1.35M
Given volume of NaOH = 637mL = 0.637L
Moles of NaOH will be calculated as:
M = n/V
n = 1.35M × 0.637L = 0.859 moles
So, 0.859 moles of NaOH = produce 0.859×1/2 = 0.429 moles of Mg(OH)₂
Now, we convert this moles into grams by using the above formula:
0.429 = W/58.31 g/mole
W = 25.07grams
Hence, 25.07grams is the theoretical yield of magnesium hydroxide.
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ii) Adding common salt to distilled water makes it a) Good conductor b) Insulator c) Both a &b a
Answer:
Explanation:
Salt + water gives an adequate conductor. It is not absolutely wonderful like silver, but it will conduct electricity to varying degrees depending on the depth of salt water that the conductor is held at.
I'd say A.