After 160 years, the activity level of the sample will be 0.5 curies.
What is half-life?Half life of any radioactive waste is the half decay of that product.
The formula is [tex]\dfrac{\lambda }{\lambda_1} = 2^\dfrac{a}{b}[/tex]
Where, λ is 4 cruies
λ1 is 0.5 cruies
b = 40 years
Putting the values in the equation
[tex]\dfrac{4}{0.5} = 2^\dfrac{a}{40}\\\\\\\dfrac{a}{40} = 4\\ = 160 years[/tex]
Thus, the correct option is 160 years.
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People in the southern united states imported the plant kudzu from japan to control erosion along highways kudzu now spreads so quickly that it kills many
other plants. how have humans directly impacted the environment in this example?
a introduction of a non-native species
b destruction of habitat
c disruption of a food chain
d. overexploitation
Humans directly impacted the environment by destroying of the habitat of the other plants. Hence, option B is correct.
What is Kudzu plant?Kudzu vine is known as a fast-growing plant since the '30s and 40's when the Soil Conservation Service paid about 8$ to every farmer who can plant an acre with this plant.
Kudzu overgrows and crowds out native plant population, for sunlight and nutrients. Therefore, it's considered 'invasive'.
It grows so quickly that it cannot be controlled and disturb other habitats of plants. Hence, option B is correct.
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Type the correct answer in each box. express your answer to two significant figures. you form water vapor by mixing oxygen and hydrogen at 730°c in a 5.4-liter container. this is the equation for the reaction: o2(g) 2h2(g) → 2h2o(g). the partial pressure of oxygen before the reaction is 122.3 kilopascals, and there is excess hydrogen. how many moles of water are formed? the reaction produces moles of water.
The number of moles of water vapor formed in the reaction is 0.158 moles
What is the ideal gas equation?The ideal gas equation shows the relationship between number of moles, temperature, volume and pressure.
Now;
P = 122.3 kilopascals or 1.21 atm
V = 5.4 L
T = 730°c or 1003 K
n = ?
R = 0.082 atmLK-1mol-1
PV = nRT
n = PV/RT
n = 1.21 * 5.4/0.082 * 1003
n = 6.53/82.2
n = 0.079 moles
The equation of the reaction is; O2 (g) + 2H2(g) ---->2H2O(g)
If 1 mole of O2 formed 2 moles of H2O
0.079 moles of O2 yield x moles of H2O
x = 0.079 * 2/1
= 0.158 moles
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An atom has eight protons and nine neutrons. draw the atomic structure of the atom
An atom has eight protons and nine neutrons. The atomic structure of the atom is attached below in image.
What is an atomic structure ?The term "atomic structure" describes the structure of an atom, which has a nucleus that contains both protons and neutrons . The centre of the nucleus is circled by the negatively charged electrons.
The smallest piece of ordinary matter within an element is called an atom. Protons, neutrons, and electrons are the three subatomic particle types that make up an atom.
An isotope's number is equal to the sum of its protons plus neutrons since their masses are almost identical. Oxygen 16 therefore has 8 protons and 8 neutrons, followed by oxygen 17 with 8 protons and 9 neutrons, and oxygen 18 with 8 protons and 10 neutrons.
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Help!! fast pls. what is the second quantum number for one of the electrons in the 4p energy sub level of bromine
The second quantum number for one of the electrons in the 4p energy sub level of bromine is l = 1 .
What are Quantum Numbers ?Those set of numbers which describe the energy level and position of an electron are called Quantum Numbers.
There are 4 types of quantum numbers :
Principle Quantum Numbers
Azimuthal Quantum Number
Magnetic Quantum Number
Spin Quantum number
the bromine atom the one electron in 4p energy sublevel,
it is in 4rd shell , n= 4 ,
it is in 'p' orbital l = 1
therefore value of m = -1 , 0, 1
[tex]\rm m_s[/tex] = +1/2 or -1/2
The second quantum number for one of the electrons in the 4p energy sub level of bromine is l = 1 .
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A 57.6 g sample of methane (CH4) is found to contain 43.2 g of carbon. What is the
percent composition of Carbon and Hydrogen? How much hydrogen (in grams) would a
37.8 g sample of methane contain?
Answer:
Explanation:
The atomic mass of carbon is 12.011 g/mol.The atomic mass of hydrogen is 1.00794 g/mol.This means that the atomic mass of methane is 12.011+4(1.00794)=16.04276 g/mol.
The percent composition by mass of carbon is [tex]\frac{12.011}{16.04276} \times 100=\boxed{74.9\%}[/tex]The percent composition by mass of hydrogen is [tex]\frac{4(1.00794)}{16.04276} \times 100=\boxed{25.1\%}[/tex]This means that in a 37.8-gram sample of methane, there would be [tex](37.8)\left(\frac{25.1}{100} \right)=\boxed{9.49}[/tex] grams of hydrogen.
The conductance of the electric current through the electrolytic solution increases with
a)decrease in dilution
b)increase in dilution
c)increase in concentration
d)low degree of ionization
The conductance of the electric current through the electrolytic solution increases with increase in concentration.
What is an electrolytic solution?An electrolytic solution is a solution containing dissolved electrolyte.
The ions of the electrolyte dissociate and are able to carry electric current around the electrolytic cell.
The higher the concentration of the electrolyte, the more electric current it can conduct due to greater number of ions present.
Therefore, the conductance of the electric current through the electrolytic solution increases with increase in concentration.
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Sulphuric acid (H2SO4) is extremely corrosive to skin. Which branch of chemistry is this?
1) Analytical Chemistry
2) Bio Chemistry
3) Environmental Chemistry
4) Inorganic Chemistry
Answer:
B
Explanation:
Bio Chemistry.
1. Which term identifies a factor that will shift a
chemical equilibrium?
A) atomic radius
B) catalyst
C) decay mode
D) temperature
Answer:
D) Temperature,
Explanation:
The half-life of carbon-14 is approximately 5700 years. An archaeologist unearths a piece of wood that is determined to
have 83% of its carbon-14 remaining. Using carbon-12 dating techniques, approximately how old is the ancient piece of
wood that she located?
The age of the ancient piece of wood that she located given the data is 1482 years
How to determine the number of half-lives
Original amount (N₀) = 100%
Amount remaining (N) = 83%
Number of half-lives (n) =?
2ⁿ = N₀ / N
2ⁿ = 100 / 83
2ⁿ = 1.2
Take the Log of both side
Log 2ⁿ = Log 1.2
nLog 2 = Log 1.2
Divide both side by Log 2
n = Log 1.2 / Log 2
n = 0.26
How to determine the age
Number of half-lives (n) = 0.26
Half-life (t½) = 5700 years
Time (t) =?
t = n × t½
t = 0.26 × 5700
t = 1482 years
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how many moles of pb(NO3)2 are needed to react with 4.8 moles of Al
Select the atoms that belong to the same element.
16 protons 16 neutrons 16 electrons
11 protons 10 neutrons 11 electrons 13 protons 14 neutrons 13 electrons. 14 protons 14 neutrons 14 electrons. 11 protons 12 neutrons 11 electrons
Explanation:
please structure your question correctly so that we can answer.
Answer:
Cant answer until its wrote correctly
Explanation:
Because its not stated properly
The substances sodium (Na), oxygen (O2), and sodium oxide (Na2O) participate in this chemical reaction:
4Na + O2 → 2Na2O.
Which statement best describes the reaction?
The chemical reaction involving sodium and oxygen as given in the reaction: 4Na + O2 → 2Na2O is a synthesis reaction.
What are chemical reactions?Chemical reactions are changes which occur in the chemical composition of atoms of substances which results in the formation of new substances.
There are different types of chemical reactions such as:
synthesis reactiondisplacement reactiondouble displacement reactionsA synthesis reaction is a reaction in which two or more substances combine to form a new product.
Therefore, the chemical reaction involving sodium and oxygen as given in the reaction: 4Na + O2 → 2Na2O is a synthesis reaction.
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If ba+2 will reacts with n-3, the formula of the compound formed is:
a. ban3
b. ba2n3
c. ban
d. ba3n2
If [tex]Ba^{+2}[/tex] will reacts with [tex]N^{-3}[/tex], the formula of the compound formed is [tex]Ba_3N_2[/tex].
What is an ionic compound?Ionic compounds are neutral compounds made up of positively charged ions called cations and negatively charged ions called anions.
Barium is a metal element and Nitrogen is a non-metal element, so they form an ionic compound. To make the formula of an ionic compound, first, we need to see the valence of the atoms, that is, how many electrons it can donate or it has to gain to have 8 electrons in the valence layer (octet rule).
Barium is in family 2, so it has two electrons in its valence layer, so it must donate these two electrons; Nitrogen is in family 15, so it has 5 electrons ins its valence layer and must gain 3 electrons.
Writing the ions they must form:
[tex]Ba^{+2}N^{-3}[/tex]
First came the cation (positive charge), then the anion (negative charge), and the charges must change between them, without the signal, and will inform how many atoms are necessary for which element:
[tex]Ba_3N_2[/tex]
Hence, If [tex]Ba^{+2}[/tex] will reacts with [tex]N^{-3}[/tex], the formula of the compound formed is [tex]Ba_3N_2[/tex].
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Below is the thermochemical equation for the combustion of octane.
SC8H18(l) + 25O2(g) ⇒ 16CO2 (g) + 18H2O(l), ΔH= -10,941kj
How much heat is released during the combustion of 4 moles of octane (C8H18)
Question 5 options:
-21,882 kJ
-175,056 kJ
-2,735 kJ
-10,941 kJ
Impossible to answer this question with the information provided
-5,470.5 kJ
5mol produces -10.941KJ
4 mol let produces x KJ
Solve through proportion
5/-10.941=4/x5x=-43.764x=-43.764/5x=8.756 KJ5moles of octane produces -10941KJ
1mol of octane produces 2188KJ
4mol of octane produces
2188(4)8756KJNEED ASAP PLS WILL AWARD BRAINLIEST
The table compares some characteristics of two atoms.
Charged Particles
Atom Number of Neutrons Mass Number
X 6 12
Y 7 13
Use the table to determine the number of protons for each atom. Then, choose the statement below that is true about the two atoms.
Atom X and Atom Y are in the same row, but not the same family, on the periodic table.
Atoms X and Atom Y are in the same family, but not the same row, in the periodic table.
Atom X is in a column to the right of Atom Y in the periodic table.
Atom X and Atom Y occupy the same position in the periodic table because they are isotopes.
Answer:
proton number for element X is 6
while proton number for element Y is 7
X and Y are in the same row but not the same family on the periodic table cause element X belongs to group 6 also known as carbon family while Y belongs to group 7 also known as nitrogen family
Which electrochemical cell does the illustration depict
Answer:
This depicts an electrolytic cell.
If you have 100 ml of water mixed with 100 ml of pollutant, the concentration of pollutant is
The concentration of pollutants is equal to the concentration of water.
What is concentration?The concentration of a solution is a measure of the amount of solute that has been dissolved in a given amount of solvent or solution.
The concentration of water is 100 ml and the concentration of pollutants is 100 ml .
Hence, If you have 100 ml of water mixed with 100 ml of pollutant, the concentration of pollutant is equal to water.
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Water is made of polar molecules, and oil is made of nonpolar molecules. Based on your observations, which molecules attract each other more strongly, polar molecules or nonpolar molecules? Explain your reasoning.
Based on observation of polar and non-polar molecules, polar molecules would attract each other more strongly.
What are polar and non-polar molecules?Polar molecules are those molecules that can ionize or dissociate into their respective positive and negative ions when in an aqueous solution.
Nonpolar molecules, on the other hand, are not ionic i.e. not dissociating into ions when dissolved in water.
Polar molecules like water (H2O) contains an uneven distribution of cations (+) and anions (-), hence, would be more attracted to one another than nonpolar molecules that have an even distribution of ions.
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what are the advantages of wind energy/fuel?
have complete details and also add the disadvantages
Answer:
Advantages of Wind Energy -
Free , clean , unlimited fuel . One of the Cleanest Forms of Energy · Advances in Technology · Doesn't Disrupt Farmland Operations ·5) Reduces Our Dependence of Fossil FuelsDisadvantages of Wind Energy-
Dangerous to Some Wildlife NoisyExpensive Upfront CostUnreliable/Unpredictablehttps://justenergy.com/blog/wind-energy-pros-and-cons/
hope this site might help you with the details
The rocks that make up the crust are relatively cold and ?
Answer:
brittle
Explanation:
a student used a vernier magnetic field sensor to measure the strength of the magnetic field generated by a bar magnet. at which position is the
strength of the magnetic field strongest point a or point b?
The position is the strength of the magnetic field strongest is is the place where the magnetic field leaves, being point A.
What generates a magnetic field?When an electrically charged particle moves, it creates a magnetic field. According to the laws of electromagnetism, this magnetic field originates from the variation of the electric field strength.
In the region of the poles we see that the lines of magnetic induction are closer to each other, therefore, we consider that close to the poles the magnetic field is more intense.
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When adding sugar to tea, it was observed that the sugar kept dissolving. After a
minute, all of the sugar was completely dissolved, as no extra particles can be
added and be seen floating around. The mixture is then considered to be
Answer: When adding sugar to tea, it was observed that the sugar kept dissolving. After a minute, all of the sugar was completely dissolved, as no extra particles can be added and be seen floating around. The mixture is then considered to be
Explanation:
The molecule of mixture cannot be seen hence, it will be considered as homogeneous mixture.
What is molecule?
A molecule is just a collection of more than two atoms bound together by chemical bonds; depending on the context, the phrase doesn't have to include ions that meet this requirement.
What is homogeneous mixture?Solids, liquids, as well as gases, can all be homogeneous mixtures. Through, they have almost the same look and chemical makeup.
When sugar will be dissolved, the sucrose molecules get separated from one another. The materials that make up individual molecules stay together like sucrose molecules sucrose molecules, so the molecule will not break up.
Therefore mixture can be considered as molecule and homogeneous mixture.
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PLEASE HELP! WILL GIVE BRAINLIEST:
A gas has a volume of 62.65 L at STP. At what temperature (in oC) would the volume of the gas be 78.31 L at a pressure of 612.0 mm Hg?
Please show the work <3
2.45 °C
From the Ideal gas law (Combined gas law)
PV/T = P'V'/T' .....eq 1
Where:
P - initial pressure
V - initial volume
T - initial temperature
P' - final pressure
V' - final volume
T' - final temperature.
To proceed we have to make T the subject from eq.1
Which is, T = P'V'T/PV.......eq.2
We have been provided with;
Standard temperature and pressure (STP)
P = 760 mm Hg (SP - Standard Pressure)
T = 273.15 K (ST - Standard Temperature)
V = 62.65 L
P' = 612.0 mm Hg
V' = 78.31 L
T' = ? (what we require)
Therefore, we substitute the values into eq.2
T' =
.
T' = 275.60 K
T = (275.60 - 273.15) ......To °C
T = 2.45 °C
>>>>> Answer
Have a nice studies.
Based on Figure 2, which statement best describes what happens to the amount of matter in the reaction?
A. There are 54 atoms in the reactants and 54 atoms in the products.
B. There are 15 reactants molecules that become the 15 product atoms.
C. The 15 reactants molecules are destroyed to produce energy in the form of energy
D. The fuel molecule is broken in half and each half makes molecules of water and carbon dioxide as products.
Answer:15 +18
Explanation:15 fuel +18 oxygen + 33 cd
An automobile gasoline tank holds 25.0 gal when full. how many pounds of gasoline will it hold if the gasoline has a density of 0.737 g/ml ?
The amount (in pounds) the gasoline tank will hold when full is 153.76 lb
What is density?The density of a substance is simply defined as the mass of the subtance per unit volume of the substance. Mathematically, it can be expressed as
Density = mass / volume
How to convert gallon to milliliters1 gallon = 3785.412 mL
Therefore,
25 gallon = 25 × 3785.412
25 gallon = 94635.3 mL
How to determine the mass Density = 0.737 g/mLVolume = 94635.3 mLMass =?Mass = Density × Volume
Mass = 0.737 × 94635.3
Mass = 69746.2161 g
How to convert grams to pounds453.592 g = 1 lb
Therefore,
69746.2161 g = 69746.2161 / 453.592
69746.2161 g = 153.76 lb
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Activity 1: "PEA-ce of Cake"
OBJECTIVE: Identify the genotypic and phenotypic ratios of offspring in the standard monohybrid cross.
Parent 1: _______________
Garden pea plant with homozygous gene pair for round seed
Garden pea plant with homozygous gene pair for wrinkled seed
Genotype (Parent 1): _______________
RR
rr
Parent 2: _______________
Garden pea plant with homozygous gene pair for round seed
Garden pea plant with heterozygous gene pair for round seed
Genotype (Parent 2): _______________
RR
Rr
The genotype and phenotype ratio for the first cross will be 100% Rr and 100% round seeded while that of the second cross will be 1RR:1Rr and 50/50 round/wrinkle seeded offspring respectively.
Genotype and phenotype ratioFor the first cross:
RR x rr
Rr Rr Rr Rr
Genotype ratio: 100% Rr
Phenotype ratio - 100% round seeded
For the second cross:
RR x Rr
RR Rr RR Rr
Genotype ratio: 1RR:1Rr
Phenotype ratio = 50% round seeded and 50% wrinkle seeded.
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How many moles of a gas are contained in 2.085 L at STP?
A. 0.0931 mol
B. 10.8 mol
C. 10.3 mol
D. 1.11 mol
Saturn has a diameter of 74,898 miles. What is its diameter in kilometers? (1
mile = 1.6 kilometers)
Answer:
119836.8 km
Explanation:
74 898 miles * 1.6 km / mile = 119836.8 km
groundwater is an important resource for all life on earth. as you have read, water levels in the ogallala aquifer are decreasing. one proposed
strategy mentioned in the article is to dig deeper wells. do you agree or disagree with this strategy? use evidence and scientific reasoning to
support your position
Digging of wells being able to increase aquifer is something I agree with.
What is an Aquifer?
This is a water permeable rock layer which is found in the underground layer of the earth.
Wells will ensure water seeps into these layers thereby bringing about an increase in the aquifer.
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CH3NH₂ + H2O → what is this equal
The balanced equation is CH₃NH₂ + H₂O → CH₃NH + H₃O.
What is a chemical reaction?A chemical reaction is a reaction involves two or more reactants that reacts to form products.
When methyl amine reacts with water, then methyl amino and hydronium ion are formed.
Thus, the product of the reaction is CH₃NH₂ + H₂O → CH₃NH + H₃O.
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