The half-life of polonium-210, given that it decays from 98.3 micrograms to 12.3 micrograms in 414 days is 138 days
How to determine the number of half-lives Original amount (N₀) = 98.3 microgramsAmount remaining (N) = 12.3 microgramsNumber of half-lives (n) =?2ⁿ = N₀ / N
2ⁿ = 98.3 / 12.3
2ⁿ = 8
2ⁿ = 2³
n = 3
How to determine the half life Number of half-lives (n) = 3Time (t) = 414 daysHalf-life (t½) = ?
t½ = t / n
t½ = 414 / 3
t½ = 138 days
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The half life of the polonium-210 is 138 days.
What is Half-Life?The half-life is the time taken for half the sample to decay.
It takes 414 days for 98.3 g of to decay from 98.3 micrograms to 12.3 micrograms.
The fraction of 98.3 that is 12.3 g = 98.3/12.3 = 1/8
The sample has undergone 3 half-lives.
The half-life = 414/3 = 138 days.
In conclusion, it takes 138 days for half the sample to decay.
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the production of olefin
Answer:
Olefin production is a petrochemical process in which saturated hydrocarbons are broken down into smaller, regularly unsaturated ones
Consider the following reaction:
2KI (aq) + Pb(NO3)2(aq) -> 2 KNO3(aq) + Pbl2(s)
What minimum volume of 0.200 M Kl(aq) is required to completely react with 155.0 mL of a 0.112 M Pb(NO3)2 solution?
A. 174 mL
B. 43.4 mL
C. 86.8 mL
D. 348 mL
Answer:
B. 43.40 mL
Explanation:
We are required to determine the volume of 0.200 M Kl(aq).
We have; 155.0 mL of a 0.112 M Pb(NO3)2 solution.
We know that molarity of a solution is contained in 1 L or 1000 mL or 1000 cm³.
Hence,
0.112 M Pb(NO3)2 is contained in 1000 mLx mol Pb(NO3)2 is contained in 155.0 mL[tex]x \: mol \: = \frac{155 \times 0.112}{1000} \\ = 0.01736 \: moles[/tex]
= 0.01736 moles of Pb(NO3)2
We have a mole ratio of 2: 1 (KI : Pb(NO3)2).
To obtain the number of moles of KI; we divide by half the moles of Pb(NO3)2 (aq);
(0.01736)/2
= 0.00868 moles KI
0.20 moles KI is contained in 1000 mL
0.00868 moles KI is contained in x mL
[tex]x \: ml \: = \frac{0.00868 \times 1000}{0.20} [/tex]
= 43.40 mL
Therefore the volume of KI required to react completely with 0.112 M Pb(NO3)2 is 43.40 mL
The electron configuration of an element is 1s22s22p63s1.
Describe what most likely happens when an atom of this element comes near an atom having seven valence electrons.
The element is Sodium with an atomic number of 11 and electrovalent bonding takes place when it comes near an atom having seven valence electrons.
What is Electrovalent bonding?This is also referred to as ionic bonding and involves the transfer of atoms of an element to another.
In order for both of them to achieve a stable octet configuration, sodium donates one atom to the element seven valence electrons.
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Answer: A single electron from the outermost shell of this element will move into the outermost shell of the atom with seven electrons.
Explanation:
14. What volume of water vapor in liters could be generated at 1.01 atm and 420. K by the combustion of 273.36 grams of oxygen gas excess pentane gas (C5H12)?
C5H12(g) + 8 O2(g) ---> 5 CO2(g) + 6 H2O(g)
(OR C5 H12 ("g") + 8 O2 ("g") right arrow 5 C O2 ("g") + 6 H2 O ("g")
Do not type units with your answer
Answer:
776 L H₂O
Explanation:
To find the volume, you need to use the Ideal Gas Law. The equation looks like this:
PV = nRT
In this equation,
-----> P = pressure (atm)
-----> V = volume (L)
-----> n = number of moles
-----> R = constant (0.0821 L*atm/mol*K)
-----> T = temperature (K)
To find the volume of water vapor, you need to (1) convert grams C₅H₁₂ to moles C₅H₁₂ (via molar mass), then (2) convert moles C₅H₁₂ to moles H₂O (via mole-to-mole ratio from reaction coefficients), then (3) calculate volume H₂O (via Ideal Gas Law). The final answer should have 3 sig figs.
(Step 1 & Step 2)
Molar Mass (C₅H₁₂): 5(12.011 g/mol) + 12(1.008 g/mol)
Molar Mass (C₅H₁₂): 72.151 g/mol
1 C₅H₁₂ (g) + 8 O₂ (g) -----> 5 CO₂ (g) + 6 H₂O (g)
273.36 g C₅H₁₂ 1 mole 6 moles H₂O
----------------------- x ---------------- x ----------------------- = 22.7 moles H₂O
72.151 g 1 mole C₅H₁₂
(Step 3)
P = 1.01 atm R = 0.0821 L*atm/mol*K
V = ? T = 420 K
n = 22.7 moles
PV = nRT
(1.01 atm)V = (22.7 moles)(0.0821 L*atm/mol*K)(420 K)
(1.01 atm)V = 783.856
V = 776 L
Without units, your answer would be 776.
Skunks have scent glands that allow the animals to give off an unpleasant odor when they are frightened or uncomfortable.
What function do the scent glands have?
A.
They act as a propulsion system to propel the skunk away from predators.
B.
They attract other skunks to mate with.
C.
They protect skunks against predators.
D.
They kill insects and small animals for the skunks to eat.
Answer:
Some use them to mark their territory, while others use them as skunks do — as a defense mechanism to protect them from predators. Some animals are even named for their odor-producing ability.29 Mar 2021
Explanation:
Skunks have two glands, one on each side of the anus. These glands produce the skunk's spray, which is a mixture of sulfur-containing chemicals such as thiols (traditionally called mercaptans), which have an offensive odor. The thiols also make their spray highly flammable.
Allyl sulfide, C6H10S, is a compound that has the odor of garlic. How many moles of Allyl sulfide are in 125 g?
Considering the definition of molar mass, 1.096 moles of Allyl sulfide are in 125 g.
Definition of molar massThe molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.
The molar mass of a compound (also called Mass or Molecular Weight) is the sum of the molar mass of the elements that form it (whose value is found in the periodic table) multiplied by the number of times they appear in the compound.
Molar mass of C₆H₁₀SIn this case, you know the molar mass of the elements is:
C= 12 g/moleH= 1 g/moleS= 32 g/moleSo, the molar mass of the compound C₆H₁₀S is calculated as:
C₆H₁₀S= 6× 12 g/mole + 10× 1 g/mole + 32 g/mole
Solving:
C₆H₁₀S= 114 g/mole
Moles in 125 g CH₂Cl₂Next, you can apply the following rule of three: If by definition of molar mass 114 grams of the compound are contained in 1 mole, 125 grams of the compound are contained in how many moles?
[tex]amount of moles=\frac{125 grams x 1 mole}{114 grams}[/tex]
amount of moles= 1.096 moles
Finally, 1.096 moles of Allyl sulfide are in 125 g.
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Which of the following is true of an effective scientific model
An effective scientific model must be testable and verifiable by using the scientific method.
What is a scientific model?A scientific model is any explanation of an observation of the real world that can be proved by the scientific method.
A scientific model must be testable, which means that we can confirm or reject its assumptions through experimental and/or observational procedures.
In conclusion, the effective scientific model must be proved with the scientific method.
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Please help!!!
Tysm!! Xxxx
1) The amount of PbS produced will be 16.27 grams
2: The amount of Fe produced will be 118.72 grams.
Stoichiometric problems1) The equation is balanced. The mole ratio of lead (II) acetate to the PbS is 1:1.
Mole of 22.11 lead acetate = 22.11/ 325.29 = 0.06797 moles
Equivalent mole of PbS = 0.06797 moles
Mass of PbS = 0.06797 x 239.3 = 16.27 grams
2) from the equation, the mole ratio of Al to Fe is 1:1.
Mole of 57.2 g Al = 57.2/26.98 = 2.12 moles
Equivalent mole of Fe = 2.12 moles
Mass of Fe = 2.12 x 56 = 118.72 grams.
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Which of the following summarizes a change that takes palace as solid turns to liquid? A. particles have a decrease in mobility. B. particles move closer together. C. particles become less ordered. D. intermolecular forces between particles become stronger.
Which of the following is a group that can be measured against the experimental group. A. variable. B. responding. C. manipulated. D. contro
The change that takes palace as solid turns to liquid is that particles become less ordered. That is option C.
The group that is measured against the experimental group is control group. That is option D.
What is change of state?Change of state of a substance is the reversible changes that occurs in that substance which may include:
melting, freezing, sublimation, deposition, condensation, and vaporization.When a solid turns into liquid, it becomes less ordered because there is reduction of the intermolecular forces existing between the molecules of the substance.
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Answer: (C) particles become less ordered
Explanation:
Melting - When a solid is heated, it absorbs energy and it melts, turning into a liquid. Boiling - If the liquid is heated, it absorbs more energy and it boils, turning into a gas
If 6 moles of Al2O3 react, how many moles of O2 are produced?
Answer:
18 moles O₂
Explanation:
To convert moles of Al₂O₃ to moles O₂, you first need to determine the balanced reaction. Using the reaction coefficients, you can multiply the starting value by the mole-to-mole ratio of the desired substances.
1 Al₂O₃ ---> 3 O₂ + 2 Al
6 moles Al₂O₃ 3 moles O₂
----------------------- x ----------------------- = 18 moles O₂
1 mole Al₂O₃
Scenario A
Julio was given the task to produce 59 grams of iron(III) oxide, 23
F
e
2
O
3
. They had one tank of oxygen gas, 2
O
2
and 54 grams of solid iron,
F
e
. They knew that if he heated the iron in the presence of the oxygen gas, they could produce the iron(III) oxide. Since they had such little amount of iron, they decided to use as little of the iron as they could to produce the 59 grams of iron(III) oxide. Julio measured out 41 grams of iron and heated it with excess oxygen. Assume Julio's reaction went 100%. Julio was very happy that their reaction produced the 59 grams.
Scenario B
Gretchen was given the task to produce 19 grams of aluminum fluoride, 3
A
l
F
3
. They had a tank of fluorine gas, 2
F
2
, and 7 grams of solid aluminum,
A
l
. They knew that if they heated the aluminum in the presence of excess fluorine gas, they could produce the aluminum fluoride. Since Gretchen had such little amount of aluminum, they decided to use as little of aluminum as they could to produce the 19 grams of aluminum fluoride. Gretchen measured out 5 grams of aluminum and heated it with excess fluorine gas. Assume Gretchen's reaction went 100%. Gretchen was very happy their reaction produced the 19 grams.
Question #1: Which scientist did the experiment incorrectly? (1 pt)
Question #2: Explain what the scientist did incorrectly. Be sure to include the balanced equation for each scientist. Show the stoichiometry and explain in complete sentences why one experiment is wrong and the other is not. (4 pts)
Question #3: Explain specifically what the scientist should do to make the experiment correct (use numbers to support your answer). Also, include the stoichiometry to show how the scientist can make the experiment correct. (3 pts)
As you answer the questions above, use complete sentences to explain the stoichiometry you show and use proper grammar and spelling (1 pt)
Based on the mole ratio of the balanced equation of the reactions;
Gretchen did the experiment incorrectlyGretchen did not measure the accurate mass of aluminum required to produce 19 g of aluminum fluorideGretchen needs to react 6.1 g of Al in excess fluorine in order to produce 19 g of AlF₃What mass of iron(III) oxide is produced from reacting 41 g of Fe with excess oxygen?The equation of the reaction is given below:
4 Fe + 3 O₂ → 2 Fe₂O₃Based on the reaction, mole ratio of Fe and Fe₂O₃ is 2 : 1
Moles of Fe reacted = 41/56 moles
Mass of Fe₂O₃ produced = 41/56 * 1/2 * 160 = 58.6 g
What mass of aluminum fluoride is produced from reacting 5 g of aluminum with excess fluorine?The equation of the reaction is given below:
2 Al + 3 F₂ → 2 AlF₃Based on the reaction, mole ratio of Al and AlF₃ is 1 : 1
Moles of Al reacted = 5/27 moles
Mass of AlF₃ produced = 5/27 * 84 = 15.5 g
This is less than the required mass of AlF₃
Moles of AlF₃ in 19 g = 19/84 = 0.2262 moles
Mass of Al required = 0.2262 * 27 = 6.1 g
Based on the results above;
Gretchen did the experiment incorrectlyGretchen did not measure the accurate mass of aluminum required to produce 19 g of aluminum fluorideGretchen need to react 6.1 g of Al in excess fluorine in order to produce 19 g of AlF₃In conclusion, the mole ratio of the reactions obtained from the equation are required to know the accurate masses of reactants required.
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Which of these safety features aims to keep nuclear radiation contained
The safety feature aimed at keeping nuclear radiation contained is steel-reinforced concrete.
What is nuclear power plant?A nuclear power plant is a building with reactors that contain controlled nuclear reactions to produce energy.
Nuclear power plants are able to generate warm water by using atomic properties of matter (i.e.,m the process of nuclear fission), which is in turn converted into steam to move turbines.
The walls of nuclear power reactors are composed of steel-reinforced concrete in order to avoid radiation release.
In conclusion, the safety standard property that maintains nuclear radiation contained is steel-reinforced concrete.
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Calculate the mass of 2.11 moles of CF2Cl2. Your answer should be in grams.
WHATS THE CORRECT ANSWER ANSWER ASAP FOR BRAINLIST
Answer:
Falling water!Explanation:
Hope this helps
What are the Result of reaction between , Isoquinoline and alkali KMNO4 ?
Answer:
hydrogen
Explanation:
because it is my own ideal
A negatively charged substance is brought near the ion. What will most likely happen and why?
Answer:
The ion will attract the substance because it has more electrons than protons.
You drink part of your bottle of water, leaving 160 g in the bottle. When you purchased the water, it had a temperature of 10oC. After carrying the bottle around for awhile, you take a sip and find that the water is an unpleasantly warm 35oC. How much heat energy did the water left in the bottle absorb? Water has a specific heat capacity of 4.2 J/(g * oC).
The energy that the water in the bottle absorbed is obtained as 16800 J.
What is the specific heat capacity?The specific heat capacity of the water refers to the energy that is required to raise the temperature of 1Kg of the water by 1 degree.
Now we have the following;
mass (m) = 160 g
temperature change dT = ( 35oC - 10oC)
specific heat capacity (c)= 4.2 J/(g * oC).
Now;
H = mcdT
H = 160 g * 4.2 J/(g * oC) * ( 35oC - 10oC)
H = 16800 J
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What’s the correct answer answer asap for brainlist
Answer:
Vast Territory
Explanation:
Russia is a very big area. It makes sense that some parts vary in their climate.
Explanation:
We gujra weeeeeeeeeeeee
We gujra weeeeeeeeeeeee
We gujra weeeeeeeeeeeee
We gujra weeeeeeeeeeeee
1. Balance, to remove harmful NO gas from the jet exhaust!
_ NH3 + _ NO + _ O2 → _ N2 + _ H2O
2. Balance, to remove harmful NO2 gas from the jet exhaust!
_ NH3 + _ NO2 + _ O2 → _ N2 + _ H2O
The balanced equation are as follows:
4NH3 + 6NO → 5N2 + 6H2O8NH3 + 6NO2 → 7N2 + 12H2OHow to balance chemical reaction?A chemical equation is said to be balanced when the number of moles of each element on both sides of the equation are equal.
According to this question, two equations are given to remove harmful NO and NO2 gases from jet exhaust.
The balanced chemical equations are given below:
4NH3 + 6NO → 5N2 + 6H2O8NH3 + 6NO2 → 7N2 + 12H2OLearn more about balanced equation at: https://brainly.com/question/8062886
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what mass of water is produced from 2.5g of glucose?
From the calculation, there are 1.5 g of water produced in the reaction.
What is an equation?An equation shows the chemical transformation that takes place in a reaction vessel. In this case, the equation is; C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O.
Now;
Number of moles of glucose = 2.5g/180 g/mol = 0.014 moles
Since 1 mole of glucose produces 6 moles of water
0.014 moles of glucose produces 0.014 moles * 6 moles/ 1 mole
= 0.084 moles
Mass of water produced = 0.084 moles * 18 g/mol = 1.5 g of water
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Which is a form of atomic reaction?
Explanation:
atomic reactin is teaction
Platinum is a shiny metal material. How is this matter classified
Answer:
Noble Metals are found as pure metals becuase they are nonreactive and don't conmbine with other elements to form compounds.
Explanation:
Hope it help :)
How many moles of of ZnCl2 are in 1.5 L of a 0.2 M solution? Report your answer with one significant figure. Provide your answer below:
The moles of ZnCl₂ in 1.5 L of the 0.2 M solution is 0.3 moles.
What moles of ZnCl₂ is present in in 1.5 L of a 0.2 M solution?The moles of ZnCl₂ is present in in 1.5 L of a 0.2 M solution is calculated using the formula below:
moles = molarity x volumeMoles of ZnCl₂ = 1.5 x 0.2
Moles of ZnCl₂ = 0.3 moles
In conclusion, the moles of ZnCl₂ in the given volume of solution is determined from the molarity of the solution and the volume of solution.
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How much heat will be released (AH) if
0.1579 mol of NH3 are mixed with 0.20 mol of
O₂ in the following chemical reaction?
4 NH3(g) + O₂ (g) → 2 N₂H4 (g) + 2 H₂O(g)
AH = -286 kJ/mol
Answer:
11.29 kJ (to 4 sf)
Explanation:
Here, ammonia is the limiting reactant.
For the reaction to occur once, 4 moles of ammonia must be consumed.
Thus means that the reaction can occur 0.1579/4=0.039475 times.
Therefore, (286)(0.039475) = 11.29 kJ (to 4 sf)
HELP PLEASE!!!
Sodium bicarbonate, NaHCO3 ( MW 84.007 g/mol), is commonly known as baking soda. Sodium bicarbonate is a solid crystalline and appears as a white powder. Sodium bicarbonate has a pH of 8.3 at 77 deg F. Sodium bicarbonate can be easily be converted to sodium carbonate, Na2CO3 ( MW 105.988 g/mol) by decomposition to produce H2O and CO2. This can be accomplished by placing the sample in the oven at 176 deg F.
Unbalanced chemical equation:
NaHCO3 (s) + Heat --> Na2CO3 (s) + H20 (g) + CO2 (g)
Write the balanced chemical equation. Calculate yield of the decomposition reaction. Make sure to show your work.
Based on the law of conservation of mass, the expected yield of the decomposition reaction is 100% which is equal to the mass of the reactant.
What mass of products are formed when 1 mole of sodium bicarbonate is decomposed by heat?According to the law of conservation of mass, the mass of products formed when 1 mole of sodium bicarbonate is decomposed by heat will be equal to the mass of one mole of sodium bicarbonate.
The balanced equation of the reaction is given below:
2 NaHCO₃ (s) + Heat --> Na₂CO₃ (s) + H₂0 (g) + CO₂ (g)Molar mass of NaHCO₃ = 84. 0 g/mol
Molar mass of Na₂CO₃ = 106 g/mol
Molar mass of H₂0 = 18 g/mol
Molar mass of CO₂ = 44 g/mol
Based on the mole ratio as given in the equation of reaction,
mass of Na₂CO₃ produced = 1/2 * 106 = 53 g
mass of H₂O produced = 1/2 * 18 = 9 g
Mass of CO₂ produced = 1/2 * 44 g/mol = 22 g
Total mass of products = 53 + 9 + 22 = 84.0 g
Therefore, the yield of the decomposition reaction is equal to the mass of the reactant.
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For the decomposition of nitrosyl bromide at 10 °C
2 NOBr(g)2 NO(g) + Br2(g)
the average rate of disappearance of NOBr over the time period from t = 0 s to t = 25.7 s is found to be 7.36×10-4 M s-1.
What is the average rate of appearance of Br2 over the same time period?
M s-1.
From the calculation, the rate of appearance of Br2 is 1.472 * 10^-3 M s-1
What is the rate of reaction?The rate of reaction refers to how fast or slow that reactants disappear or the products are formed .
Now;
We know that;
-d[NOBr]/dt = 1/2 d[Br2]/dt
Hence;
d[Br2]/dt = 2[-d[NOBr]/dt ]
d[Br2]/dt = 2 (7.36×10-4 M s-1)
d[Br2]/dt = 1.472 * 10^-3 M s-1
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Sodium tungstate is Na₂WO4. Therefore, the formula for gold(III) tungstate is
Explanation:
Na2WO4 2Na+ + wo4 2-
2Au3+ + 3wo42- Au2(WO4)3
Which functional group does the molecule below contain?
HIC H
H=COH
[
Answer:
[tex]D. \ \ \ \text{hydroxyl}[/tex]
Explanation:
Alcohols are organic compounds that are composed of the hydroxyl function group ([tex]-\text{OH}[/tex]), bonded to a carbon atom of an alkyl or a substituted alkyl group. Hence, the functional group of alcohols is the hydroxyl group ([tex]-\text{OH}[/tex]).
According to the International Union of Pure and Applied Chemistry (IUPAC) nomenclature, alcohols are named by changing the -e ending of the name of the parent alkane to the suffix -ol.
For example, the alcohol molecule in the figure demonstrates a hydroxyl group bonded to a methyl group. Therefore, the name of the alcohol is methanol.
Hi all, if anyone could please help me on this question it would be appreciated, tysm!!
Answer: 69.92 Celsius
Explanation:
Enthalpy change = mass of water * specific heat * change in temperature
400g water * 4.18 J/g*celsius * 1.5K = 2.508kJ
2508 J/(138.3g*0.38 J/g*celsius) = 47.72 K
So the copper temperature was lowered by 47.72K/C when placed in water, so 22.2+47.72 = 69.92 Celsius
Hope this helps(and is correct)!
At what temperature does sulfur tetrafluoride have a density of 0.260 g/L at 0.0721 atm?
At 365 K temperature sulfur tetrafluoride have a density of 0.260 g/L at 0.0721 atm.
What is an ideal gas equation?The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
First, calculate the moles of the gas using the gas law,
PV=nRT, where n is the moles and R is the gas constant. Then divide
the given mass by the number of moles to get molar mass.
Given data:
P= 0.0721 atm
[tex]n=\frac{mass}{molar \;mass}[/tex]
[tex]R= 0.082057338 \;L \;atm \;K^{-1}mol^{-1}[/tex]
T=?
Putting value in the given equation:
[tex]\frac{PV}{RT}=n[/tex]
[tex]density = \frac{2 \;atm\; X molar\; mass}{0.082057338 \;L \;atm \;K^{-1}mol^{-1} X T}[/tex]
[tex]0.260 g/L = \frac{0.0721 \;atm\; X 108.07 g/mol}{0.082057338 \;L \;atm \;K^{-1}mol^{-1} X T}[/tex]
T = 365.2158727 K= 365 K
Hence , at 365 K temperature sulfur tetrafluoride have a density of 0.260 g/L at 0.0721 atm.
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