An archaeologist finds 14C in a sample of material to be decaying at 20 Geiger Counter clicks per second. A modern equivalent sample of the same material decays at 160 clicks per second. The half-life of 14C is 5,730 years. How old is the sample
Answer:
17188 years
Explanation:
Recall the formula;
0.693/t1/2 = 2.303/t log(No/N)
t1/2 = half life of 14C
No = initial activity of 14C
N = activity of 14C at time t
t = age of the sample
Substituting values
0.693/5730= 2.303/t log(160/ 20)
1.21 * 10^-4= 2.0798/t
t = 2.0798/1.21 * 10^-4
t = 17188 years
A potted plant is placed under a grow lamp, which provides 6,400 J of energy to the plant and the soil over the course of an hour. The specific heat capacity of the soil is about 0.840 J/g°C and the temperature goes up by 9.25°C of soil. How many grams of soil are there?
Answer:
823.7g
Explanation:
Using the formula as follows:
Q = m × c × ∆T
Where;
Q = amount of heat (J)
m = mass of substance (g)
c = specific heat capacity (J/g°C)
∆T = change in temperature (°C)
Using the information given in this question as follows:
Q = 6,400 J
m = ?
c of soil = 0.840 J/g°C
∆T = 9.25°C
Using Q = mc∆T
m = Q ÷ c∆T
m = 6,400 ÷ (0.840 × 9.25)
m = 6400 ÷ 7.77
m = 823.7g
Answer:
There are 823.68 grams.
Explanation:
Calorimetry is responsible for measuring the amount of heat generated or lost in certain physical or chemical processes.
Between heat and temperature there is a relationship of direct proportionality. The constant of proportionality depends on the substance that constitutes the body and its mass, and is the product of the specific heat by the mass of the body. In summary, the amount of heat Q that receives or transmits a mass m of a substance with specific heat C to raise its temperature from T1 to T2 is given by the formula:
Q= C*m* (T2- T1) = C*m* ΔT
In this case:
Q= 6400 JC= 0.840 [tex]\frac{J}{g*C}[/tex]m= ?ΔT= 9.25 CReplacing:
6400J= 0.840 [tex]\frac{J}{g*C}[/tex] *m* 9.25 C
Solving:
[tex]m=\frac{6400 J}{0.840 \frac{J}{g*C} *9.25 C}[/tex]
m=823.68 grams
There are 823.68 grams.
What will be produced at the cathode during the electrolysis of an aqueous solution of magnesium iodide, MgI2
Answer:
At the cathode during the electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced
Explanation:
At cathode, reduction reaction takes place.
The dissociation of MgI2 in aqueous solution is Mg2+(aq) and 2I−(aq)
Here, the Iodine reduces to 2I−(aq) from state of 0 (MgI2) to state of -1 (2I−(aq))
Hence, at the cathode during the electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced
Answer:
During electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced at the cathode
Explanation:
Electrolysis is a process whereby ionic compound is broken down or degraded into smaller substances when electric current flow through it.
During electrolysis of magnesium iodide, At the cathode reduction reaction occur .
MgI2 is dissociated to is Mg2+(aq) and 2I−(aq)
Then Iodine is reduced to 2I−(aq) which is 0 in (MgI2) then change to -1 (2I−(aq))
Therefore;
During electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced at the cathode.
If 10.0 moles of NO are reacted with 6.0 moles of O2, How many moles of NO2 are produced?
Answer:
We have to find out which of the reactants that is the Limiting Reagent.
The Limiting Reagent is the reactant that finishes before reaction is complete or simply put... Its the reactant that's NOT IN EXCESS.
We use the reactant that's not in excess to find the Number of moles of product because once that reactant is used up.... The reaction also ends or stops(hence the name;Limiting reactant).
Now
We have 10moles of NO
We also have 6moles of O2
The balanced equation of Reaction is
2NO + O2 ===> 2NO2
Now
looking at this equation
2moles of NO is required to react with 1mole of O2
So since we have NO=10moles and O2 = 6moles
It means that
20moles of NO is required to react with 6 moles of O2.
We were only given 10moles of NO and this is not even enough to react with the whole 6moles of Oxygen because from what we just discovered... We need 20moles of NO to react with all 6moles of O2.
So
This means that NO is the LIMITING REACTANT. It is in short supply and would be used up before the whole reaction takes place.
So we use the limiting reactant to find the Number of Moles of Product formed.
Now
From the eqn of reaction
2moles of NO forms 2Moles of NO2.
Their Mole ratio is 2:2 or 1:1...
This simply means that an equal amount of NO2 will be Produced
MEANING.... 10 MOLES OF NO2 IS PRODUCED.
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What would the IUPAC name be?
Answer:
methyl ethanoate
Explanation:
To name the compound given above, the following must be obtained:
1. Determine the functional group of the compound.
In this case, the functional group is R–COOR' where R and R' are alkyl groups. Thus, the compound is an ester.
2. Determine the longest chain before the functional group and the compound after the functional group.
In this case, the longest chain before the functional group is carbon 2 i.e ethane and the compound after the functional group is methyl.
3. Name the compound by naming the compound after the functional group first, followed by the compound before the functional group and ending it with –oate.
This is illustrated below:
After the functional group => methyl
Before the functional group => ethane
Name of the compound => methyl ethanoate
Which is the same as moving the decimal point 3 places to the left in a decimal
number?
Multiplying the number by 100
Dividing the number by 1,000
Multiplying the number by 1,000
Dividing the number by 100
Answer:
B. Dividing the number by 1,000
Explanation:
Every time you move the decimal ,add a zero.Since the decimal is moved three times ,there are three zeroes. When you move left ,the number is getting smaller so it is division.
hello HELP ME pLS ANYONE with this question I will give u 18 points pls I need real help here:((
Answer:
Boiling - The process of a liquid changing to gas.
Boiling point - The temperature at which a liquid boils.
Condensing - The process of a gas changing to a liquid.
Distillate - The liquid collect from the condenser.
Residue - The liquid left behind in the distillation flask.
Vapour - Another name for gas.
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Give two examples of each of the following:
1.) Physical systems designed by people.
2.) Naturally occurring physical systems.
3.) Social systems that you are a part of.
4.) Naturally occurring social system.
A chemical bond formed when two atoms share three pairs of electrons is a ________ bond; it is best described as ________.
Answer:
Explanation:
A chemical bond formed when two atoms share three pairs of electrons is a triple bond; it is best described as covalent.
Write the formulas for each of the compounds in the following table.
1.
Ferric sulfate
2.
Strontium oxalate
3
.
Chromic acid
4.
Nickel(III) carbonate
5.
Silver bromate
6
.
Dinitrogen difluoride
1.
Magnesium molybdate
8.
Sodium hydrogen phosphate
Answer:
1. Ferric sulfate - Fe2(SO4)3
2. Strontium oxalate – SrC2O4
3. Chromic acid – CrO3
4. Nickel (III) carbonate – NiCO3
5. Silver bromate – AgBrO3
6. Dinitrogen difluoride - N2H2
7. Magnesium molybdate – MgMoO4
8. Sodium hydrogen phosphate - Na2PO4
The MO diagram of CN is similar to N2. Based on the molecular orbital energy-level diagram of CN, which of the following statements are correct?
i. The CN bond order is 2.
ii. CN is diamagnetic.
iii. The bond enthalpy in CN- ion is higher than CN.
iv. CN has longer bond length than CN-
answer choices:
a. ii, iv
b. iii, iv
c. i, iii
d. i, ii
e. i, iv
Answer:
Nitrogen molecule (N2)
The electronic configuration of nitrogen (Z=7) = 1s2 2s2 2px12py12pz1.
The total number of electrons present in the nitrogen molecule (N2) is 14.
In order to maximize energy, these 14 electrons can be accommodated in the different molecular orbitals.
N2: KK'(σ2s)2 (σ*2s)2 (π2Px)2 (π2py)2 (σ2pz)2
Here (σ1s)2 (σ*1s)2 part of the configuration is abbreviated as KK’, which denotes the K shells of the two atoms. In calculating bond order, we can ignore KK’, as it includes two bonding and two antibonding electrons.
The bond order of N2can be calculated as follows:
Here, Nb = 10 and Na = 4
Bond order = (Nb−Na) /2
B.O = (10−4)/2
B.O = 3
So your answer should be C3.
Radium has a half-life of 1500 years. How long will it take for 250kg of Radium to decay down to less than 10kg
Answer:
6967 years
Explanation:
The radioactive substance left after a periodical t year can be expressed by using the formula:
[tex]Q(t) = Q_oe^{-kt}[/tex]
here;
[tex]Q_o[/tex] = the radioactive initial value.
We need to understand that provided that the radioactive substance will get reduced to half of the provided initial amount after a periodic time, Then:
the half-life of the radioactive substance left is:
[tex]Q(h) = \dfrac{Q_o}{2}[/tex]
Given that:
the half-life = 1500 years
[tex]\dfrac{Q_o}{2}= Q_o e^{-k\times 1500} \\ \\ \dfrac{Q_o}{2}= Q_o e^{ -1500k}[/tex]
Divide both sides by [tex]Q_o[/tex]
[tex]\dfrac{1}{2} =e^{-1500k}[/tex]
Then, find the natural logarithm of both side;
[tex]\mathtt{In \dfrac{1}{2} = -1500 k}[/tex]
[tex]k = \dfrac{1}{-1500}\mathtt{In}\dfrac{1}{2}[/tex]
k = 0.000462
So, after a particular (t) time, a 250 kg radium sample was reduced to 10 kg;
Then:
[tex]10 = 250 e^{-0.000462t}[/tex]
[tex]0.04 = e^{-0.000462t}[/tex]
From both sides, finding the natural logarithm, we have:
In(0.04) = -0.000462t
[tex]t = \dfrac{In(0.04)}{-0.000462}[/tex]
t = 6967.26
Thus, it will take approximately 6967 years for a 250 kg radium sample to get reduced to 10 kg.
What is the total mass of products formed when 64.18 grams of CH4 is burned with excess oxygen?
Look at the reaction below. Upper H subscript 2 upper S upper O subscript 4 (a q) plus upper C a (upper O upper H) subscript 2 (a q) right arrow upper C a upper S upper O subscript 4 (a q) plus 2 upper H subscript 2 upper O (l). Which substance is the base in the reaction? A. 2H2O (l) B. H2SO4 (aq) C. CaSO4 (aq) D. Ca(OH)2 (aq)
Answer:
Its D
Explanation:
Did it on edge
According to the reaction: H₂S0₄ + Ca(OH)₂ → CaSO₄+ 2H₂O, the base is Ca(OH)₂.
What is a base?Base is defined as a substance which can accept protons or any chemical compound that yields hydroxide ions (OH-) in solution.
Generally, base are substances that produces hydroxide ion when dissolve in water.
Base are substances that reacts with acid to produce salt and water. Example of base includes sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide etc.
Therefore, according to the reaction:
H₂S0₄ + Ca(OH)₂ → CaSO₄+ 2H₂O
The base is Ca(OH)₂.
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Calculate the equilibrium solubility of silver arsenate
(Ksp = 6 * 10-23) in a solution that buffered to a pH of :
a) 3
b) 6
c) 9
For H3ASO4
Ka1 = 5 * 10-3
Ka2 = 1.1 * 10-7
Ka3 = 3.2 * 10-12
Answer:
sorry don't know the answer!!!
A 136 g sample of an unknown substance was heated from 20.0 °C to 40.0 °C. In the process the substance absorbed 2440 J of energy. What is the specific heat of the substance? Identify the substance among those listed in Table 2.
A. the specific heat is 0.897 J/g.C, The Substance is aluminum
B. the specific heat is -0.897 J/g.C, The Substance is aluminum
C. the specific heat is 4.184 J/g.C, The Substance is water
D. there's not enough information to determine which is the substance.
Answer:
Option A. The specific heat is 0.897 J/gºC, The Substance is aluminum.
Explanation:
We'll begin by calculating the change in temperature of the substance. This can be obtained as follow:
Initial temperature (T₁) = 20.0 °C
Final temperature (T₂) = 40.0 °C
Change in temperature (ΔT) =?
ΔT = T₂ – T₁
ΔT = 40 – 20
ΔT = 20 °C
Finally, we shall determine the specific heat capacity of the substance. This can be obtained as follow:
Mass (M) = 136 g
Change in temperature (ΔT) = 20 °C
Heat (Q) absorbed = 2440 J
Specific heat capacity (C) =?
Q = MCΔT
2440 = 136 × C × 20
2440 = 2720 × C
Divide both side by 2720
C = 2440 / 2720
C = 0.897 J/gºC
Comparing the specific heat capacity (i.e 0.897 J/gºC) of the substance with those in the table above, the substance is Aluminum.
Thus, option A gives the correct answer to the question.
THIS NOT MY WORK. its for my sister. HELP HER
Answer:
Your answer will be b(molten material from the outer core makes its way to the surface of earth)
Explanation:
Answer:
C
Explanation:
I'm pretty sure molten material comes from the inner core. I think you can search up this though, try to find where molten material comes from. Goodluck!
does iodine occur naturally in salt ? yes or no
Answer:
[tex]yes[/tex]
Explanation:
Iodine is present in salt which makes it salty:)
Consider the reaction 4FeS2 + 11O2 → 2Fe2O3 + 8SO2. If 8 moles of FeS2 react with 15 moles of O2, what is the limiting reactant? (3 points)
SO2
O2
Fe2O3
FeS2
Answer:
O2
Explanation:
for find the limiting reactant you must calculate the moles of the reactants from the amount that you have and from the MM:
MM FeS2 = 120n = 26.2g / 120g/mol = 0,218 mol
MM O2 = 32n = 5,44g/32g/mol = 0,17 mol
The limiting reactant is
O2
Please someone help me!
I need this done ASAP *URGENT*
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What’s the difference worksheet
Atoms,molecules,elements and compounds
PLEASE PLEASE PLEASE PLEASE PLEASEEEEEEE ANSWER THIS I only have TWO days of school left! And I need this done quickly
To solve this we must be knowing each and every concept related to chemical formula. Therefore, in the above given ways the chemical formula for the molecule can be written.
What is chemical formula?A chemical formula is a scientific notation that uses atomic symbol and numerical subscripts to represent the number and types of elements contained in a molecule. A chemical formula seems to be a concise written description of an existing three-dimensional molecule.
A chemical formula characterizes a material to the atomic level. There are three sorts of chemical formulas: empirical, molecular, and structural.
The chemical formula for the given molecules are:
2. H[tex]_2[/tex]O
3. O[tex]_3[/tex]
4. H[tex]_2[/tex]
5. CO[tex]_2[/tex]
6. CO
7. NO[tex]_2[/tex]
8. CH[tex]_4[/tex]
Therefore, in the above given ways the chemical formula for the molecule can be written.
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El osmio es un metal sólido que tiene una densidad
de 22 600 kg/m?, ¿qué volumen ocuparán 100 g de
este metal?
Answer:
4.42x10⁻⁶ m³
Explanation:
Primero convertimos 100 gramos a kilogramos:
100 g / 1000 = 0.100 kgAhora se puede calcular el volumen que ocuparán 0.100 kg de osmio, usando la densidad dada por el problema:
Densidad = masa / Volumen22600 kg/m³ = 0.100 kg / volumenvolumen = 4.42x10⁻⁶ m³La respuesta es 4.42x10⁻⁶ m³.
How do isotopes of the same atom react chemically? How do isotopes of the same atom compare in size?
Atoms of the same elements differing in the number of neutrons in their nuclei are known as isotopes. Thus, isotopes of an element have the same atomic number but different atomic mass number. Isotopes of an element have similar chemical properties but different physical properties.
Magnesium metal reacts with a solution of silver nitrate in a single-replacement reaction, producing aqueous magnesium
nitrate and silver metal.
If a reaction starts with 0.480 mol Mg, how many moles of silver are produced?
You must show a proper set up for the calculation, the answer with a proper unit, and
the proper significant figures.
Answer:
0.960 mol of Ag
Explanation:
Mg(s) + 2AgNO3(aq) → Mg(NO3)2(aq) + 2Ag(s)
1.00 mol of Mg ---- 2.00 mol of Ag
0.480 mol of Mg ---- x
x = (0.480×2)/1 = 0.960 mol of Ag
In the ground state, the valence electrons of a krypton atom are found in
1. The first shell
2. The outermost shell
3. Both the nucleus and the first shell
4. Both the first shell and the outermost shell
Answer: 2. The outermost shell
Explanation:
In an elements ground state, its electrons have the least amount of energy that they could have so they stay in their shells. When Krypton is in this state therefore, its valence electrons will stay in the outermost shell.
As Krypton has a total of 36 electrons in this state, there will be 8 valence electrons and they will all be in the outer shell.
Based on this chart, which of the following statements describes sources of
energy in the United States?
Sources of Energy
Petroleum
3796
Other
91%
Natural Gas
24%
Renewable
Energy
7%
Coal
2396
*Nuclear
Electric Power
8%
A. Most energy comes from nuclear power and renewable sources.
B. Most energy comes from nonrenewable energy sources.
C. Most energy comes from sources in the solid phase.
D. Most energy comes from greenhouse gases.
Answer:
B. Most energy comes from non-renewable sources
Explanation:
A P E X
In United States Most energy comes from non-renewable energy sources, as petroleum coal and others has the highest consumption in the given chart
What is the energy source in US?In the given chart, the energy consumption in US is based on Petroleum, coal and others the highest consumption pattern as compared to other energy sources
Hence, most energy in the US is from non-renewable energy sources
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About how long did it take for this population to reach the carrying capacity of this habitat
Answer:100
Explanation:
The student kicks the soccer ball three times and I shouldn’t record the distance the amount of time the ball travels and the average speed in the table shown below soccer ball girl how many seconds did it take for the ball to travel 30 m during kick three
Answer: D it’s is 2.0 s
i think..
Explanation:
How many moles of O2 did you produce the 8.31 moles of H2O
the equation is not present.
How many grams of oxygen are necessary to react completely if you have 4.0 moles of oxygen
Answer:
1.3 × 10² g
Explanation:
Step 1: Given data
Moles of oxygen: 4.0 mol
Step 2: Calculate the mass corresponding to 4.0 moles of oxygen
For a given chemical reaction, we need 4.0 moles of oxygen and we want to find what mass in grams it represents. To convert moles to mass, we need a conversion factor: the molar mass. The molar mass of oxygen is 32.00 g/mol.
4.0 mol × 32.00 g/mol = 1.3 × 10² g
In which substance are molecules moving the fastest? The options are, a. Solid water (ice) b. Liquid water c. Water vapor (gas)
Answer:
The answer is C
Explanation:
The more space the molecules have the faster they will move, solid doesn't allow movement at all, when it gets to liquid they are free to move around because it's more space, when a gas they can move all around in the air.