Answer:
38.3 g
Explanation:
The half life of a substance is the time taken for the substance to decay to about half of its amount.
Let us assume that I-125 have a half life of 60 days. It means that every 60 days, the amount of I - 125 would be halved.
The amount of I - 125 (A) that remains after t days is given by:
[tex]A=A_o*\frac{1}{2^n} \\[/tex]
Where Ao is the initial amount and n = t / half life
Given that:
Ao = 300 g, t = 178.2 days.
Therefore n = t / half life = 178.2 days / 60 days = 2.97
[tex]A=A_o*\frac{1}{2^n} \\A=300*\frac{1}{2^{2.97}}\\ A=38.3\ g[/tex]
Find the molar mass of s6
Moles: 1
Weight, g : 192.3900
Answer:
Moles: 1
Weight, g : 192.3900
Explanation:
In a reaction, 25 grams of reactant
AB breaks down into 10 grams of
product A and an unknown amount
of product B. Using the law of conservation of mass, how much does product B weigh?
a. 25 g
B. 10 g
С. It cannot be determined from the given
information.
d
D. 15g
Answer:
D. 15g
Explanation:
The law of conservation of mass states that, in a chemical reaction, mass can neither be created nor destroyed. This means that the amount of matter in the elements of the reactants must be equal to the amount in the resulting products.
In this question, 25 grams of a reactant AB, was broken down in a reaction to produce 10 grams of products A and X grams of product B. According to the law of conservation of mass, the mass of the reactant must be equal to the total mass of the products. This means that 25 grams must also be the total mass of both products in this reaction. Hence, if product A is 10 grams, product B will be 25 grams - 10 grams = 15 grams.
Therefore, product B must be 15 grams in order to form a total of 25 grams when added to the mass of product A. This will equate the mass of the reactant AB and fulfill the law of conservation of mass.
What is the name of the body part that passes messages
from the sensory neurons to the brain?
o Lungs
O Nerve Cells
o Brain
o Stimulus please help me thanks
A sample of octane undergoes combustion according to the equation 2 C8H18 + 25 O2 → 16 CO2 + 18 H2O ΔH°rxn = -11018 kJ. What mass of O2 (in grams) must react in order to generate 7280 kJ of energy?
Answer:
[tex]\large \boxed{\text{528.7 g} }[/tex]
Explanation:
It often helps to write the heat as if it were a reactant or a product in the thermochemical equation.
Then you can consider it to be 11018 "moles" of "kJ"
We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
M_r: 32.00
2C₈H₁₈ + 25O₂ ⟶ 16CO₂ + 8H₂O + 11 018 kJ
n/mol: 7280
1. Moles of O₂
The molar ratio is 25 mol O₂:11 018 kJ
[tex]\text{Moles of O}_{2} = \text{7280 kJ} \times \dfrac{\text{25 mol O}_{2}}{\text{11 018 kJ}} = \text{16.52 mol O}_{2}[/tex]
2. Mass of O₂
[tex]\text{Mass of C$_{8}$H}_{18} = \text{16.52 mol O}_{2} \times \dfrac{\text{32.00 g O}_{2}}{\text{1 mol O}_{2}} = \textbf{528.6 g O}_{2}\\\text{The reaction requires $\large \boxed{\textbf{528.67 g O}_{2}}$}[/tex]
The conversation of cyclopropane to propene in the gas phase is a first order reaction with a rate constant of 6.7x10-⁴s-¹. a) if the initial concentration of cyclopropane was 0.25M , what is the concentration after 8.8min?b) how long (in min) will it take for the concentration of cyclopropane to decrease from 0.25M to 0.15M?
Answer: a) The concentration after 8.8min is 0.17 M
b) Time taken for the concentration of cyclopropane to decrease from 0.25M to 0.15M is 687 seconds.
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) concentration after 8.8 min:
[tex]8.8\times 60s=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\log\frac{0.25}{a-x}[/tex]
[tex]\log\frac{0.25}{a-x}=0.15[/tex]
[tex]\frac{0.25}{a-x}=1.41[/tex]
[tex](a-x)=0.17M[/tex]
b) for concentration to decrease from 0.25M to 0.15M
[tex]t=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\log\frac{0.25}{0.15}\\\\t=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\times 0.20[/tex]
[tex]t=687s[/tex]
What volume of 10,0 M H2SO4 is required to prepare 4.0 L of 0.50 M H2SO4?
A) 0.20 L
B) 0.40 L
C) 0.50 L
D) 1.0L
E) 4.0L
Answer: A) 0.20 L
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.
According to the neutralization law,
[tex]M_1V_1=M_2V_2[/tex]
where,
[tex]M_1[/tex] = molarity of stock [tex]H_2SO_4[/tex] solution = 10.0 M
[tex]V_1[/tex] = volume of stock [tex]H_2SO_4[/tex] solution = ?
[tex]M_2[/tex] = molarity of dilute [tex]H_2SO_4[/tex] solution = 0.50 M
[tex]V_2[/tex] = volume of dilute [tex]H_2SO_4[/tex] solution = 4.0 L
[tex]10.0\times V_1=0.50\times 4.0[/tex]
[tex]V_1=0.20L[/tex]
Therefore, the volume of 10.0 M [tex]H_2SO_4[/tex] solution needed to prepare 4.0 L of 0.50 M [tex]H_2SO_4[/tex] is 0.20 L
An element and an atom are different but related because
a) A particular element is made up of many different types of atoms b) A molecule is the same as an atom
c) An element is made up of all the same type of atom
d) An element is smaller than an atom
Answer:
c) An element is made up of all the same type of atom
Explanation:
Atoms are the smallest unit of an element that consists of protons, electrons and neutrons in its structure. An element is the smallest part of a chemical substance that cannot be disintegrated i.e. it cannot be broken down further.
Atoms and elements are different in many ways but they are connected in the sense that an element contains only one type of atoms. For example, aluminum element is made up of only aluminum atoms. Different atoms form a molecule but same atoms form an element.
The difference of the element and iron should be option c) An element is made up of all the same type of atom.
What are atoms and elements?The atom represents the smallest unit that comprises of protons, electrons, etc.
While on the other hand, the element represents the small part of the chemical substance that should not be disintegrated. Also, it cannot be split. They both should be interlinked.
Therefore, the option c is correct.
Learn more about an atom here: https://brainly.com/question/15893771
A skeleton chemical equation includes which of the following
Answer:
Explanation:
Skeleton equations are also known as unbalanced equations.
Eg I react Oxygen, Hydrogen and Chlorine and I get Water and Chlorine Gas
H2 + Cl2 = HCl
Left Side
H = 2
Cl = 2
Right Side
H = 1
Cl = 1
As you can see it's not balanced is skeleton equation.
which of the following is a basic salt solution?
A. NH3 (aq)
B. NH4I (aq)
C. KNO3 (aq)
D. Na2CO3 (aq)
Answer:
D. Na2CO3
Explanation:
I'm just guessing tbh
ASAP plz I will give the brainliest
Which type of bond describes the coming
together and sharing of two unpaired outer
electrons, one from each atom?
a. Single covalent bond
b. Double covalent bond
С. Triple covalent bond
d. lonic bond
2nd question
What is the name of this molecule (CO2) that
forms by burning of fuels and is one of the
gases that contributes to global
warming/climate change?
A. Carbon oxygen
B. Carbon and two oxygen
C. Carbon dioxide
D. Carbon oxide
Answer:
Question 1
Which type of bond describes the coming together and sharing of two unpaired outer electrons, one from each atom?
A. Single covalent bond.
Definition of single covalent bond:
A single covalent bond is when only one pair of electrons is shared between atoms.
Question 2
What is the name of this molecule (CO2) that forms by burning of fuels and is one of the gases that contributes to global warming/climate change?
C. Carbon dioxide.
Balance the following chemical
equation by providing the correct
coefficients.
_FeBr3 +_Na2S -> _Fe2S3 + _NaBr
Answer:
2FeBr3 + 3Na2S ➡️ Fe2S3 + 6NaBr
4. What is the name of A13+?
A)Aluminum ion
B)Aluminum
C)Aluminous ion
D)Aluminide ion
Answer:
Aluminum ion
Explanation:
I used Google tbh but it has a higher charge then a regular Aluminum atom
4. If 175 undecayed nuclei remain from a sample of 2800 nuclei, how many half-
lives have passed? (Show your work.) *
Your answer
Answer:
X = 4
Explanation:
Start 2800
End 175
175 = 2800x(0.5)^X
175/2800 = 0.5^X
0.0625 = 0.5^X
log(0.5 x) = log(0.0625)
x · log(0.5) = log(0.0625)
-0.301x = -1.204
x = -1.204/-0.301
x = 4
A. Element
B. Compound
C homogenous mixture
D heterogenous mixture
If two electrically charged objects repel one another, which statement must be true? One object has more electrons, and the other has more protons. Electrons will flow from one object to the other when they touch each other. The two objects have the same electric charge. The objects do not have strong electrical fields.
Answer:
The two objects have the same electric charge.
Explanation:
Electrically charged objects repel if they are both of the same charge, ie plus plus or minus minus.
The statement, that describes two electrically charged objects repel one another is "the two objects have the same electric charge."
What is an electric charge?The feature of subatomic particles that causes them to experience a force when put in an electric and magnetic field is known as electric charge.
When one or more items are electrically charged, electrostatic interactions are widespread. Two items with opposing charges will attract each other.
Unlike the attractive force between two items with opposite charges, two objects with like charges repel each other. In other words, a positively charged object will repel another positively charged object. This repelling force will separate the two items.
Hence the correct answer is the two objects have the same electric charge.
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An electron is in a region outside the nucleus. An electron
a) Is larger than a proton and has no charge
b) Has less mass than a proton and has a negative charge
c) Is smaller than a proton and has no charge
d) Has a positive charge
Answer:
b
Explanation:
electrons lie in the orbits of the atom. they are negatively charged and they are very small in size. they have very less mass than proton. ele tron has 1/1840 mass of proton.
Which phase lasts longer, a full moon or a new moon?
Select one: a. Full moon
b. New moon
C. They both last for the same number of days.
Answer: Definitely the answer is C. They both last for the same number of days.
Explanation: This requires the moon to complete a bit more than one orbit to be between the earth and the sun again. The period from new moon to full moon is one half a synodic month of 29.530/2 which is 14.765 days.
Most scientists recommend reducing carbon dioxide emissions. Less carbon dioxide in the atmosphere would be expected to?
Answer:
the air would be much cleaner and better for us to breath.
Explanation:
PLEASE HELP ME OUTTTT
How many grams of Fe3O4 are required to react completely with 54.29 grams of H2?
Fe3O4 + H2 → Fe + H2O
Answer:
Balance the equation
Fe3O4 + 4H2---> 3Fe +4H2O
Molar mass H2=(2*1)=2g/mol
Mass of H2=54.29grams
mole of H2= 54.29/2=27.15mol
4 mol of H2 = 1 mol Fe3O4
27.15mol of H2= 6.79mol of Fe3O4
Moles of Fe3O4 =6.79mol
Molar mass of Fe3O4= (56×3)+(16×4)
=168+64=232g/mol
Grams of Fe3O4 required to react with 54.29 grams of H2 is 232g/mol× 6.79mol
=1575.28g
What are these labels?
Answer:
From left to right
Neutral
Acid
Base
Explanation:
So using HSAB theory hard and soft (Lewis) acids and bases.
OH - Is a Hard Base
H+ Strong Acid
Which image shows a nonrenewable resource?
Answer: The orange can shall be your answer.
fill in the blank
_______ is a gaseous state of matter that contains appreciable numbers of electrically charged particles.
Diamond is harder than graphite. This is a _______ observation.
Chemistry is defined as the study of _______.
Answer:
1. plasma; 2. qualitative; 3. matter;
Explanation:
PLASMA is a gaseous state of matter that contains appreciable numbers of electrically charged particles.
Diamond is harder than graphite. This is a QUALITATIVE observation.
Chemistry is defined as the study of MATTER.
Plasma is a gaseous state of matter that contains appreciable numbers of electrically charged particles.Diamond is harder than graphite. This is a qualitative observation.Chemistry is defined as the study of matter.
What is matter?Matter in chemistry, is defined as any kind of substance that has mass and occupies space that means it has volume .Matter is composed up of atoms which may or not be of same type.
Atoms are further made up of sub atomic particles which are the protons ,neutrons and the electrons .The matter can exist in various states such as solids, liquids and gases depending on the conditions of temperature and pressure.
The states of matter are inter convertible into each other by changing the parameters of temperature and pressure.Matter is always conserved according to law of conservation of matter.
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When we move from the bottom to the top of the periodic table:
Electronegativity increases and ionisation energy decreases
Both electronegativity and ionisation energy decreases
Both electronegativity and ionisation energy increases
They remain the same
Answer:
When we move from the bottom to the top of the periodic table:
Both electronegativity and ionisation energy increases.
Explanation:
The ionization energy I is the energy needed to start an electron to a gaseous atom, isolated and in a fundamental state. The electrons are attracted to the nucleus, so it is necessary to provide energy to start them. You should keep in mind that the electrons of the last layer are always lost, because they are the weakest attracted to the nucleus.
In a group, the ionization energy increases upwards because when passing from one element to the bottom, it contains one more layer of electrons. Therefore, the valence layer electrons, being further away from the nucleus, will be less attracted to it and it will cost less energy to pluck them.
On the other hand, electonegativity is defined as the ability of an element to attract electrons that link it to another element.
When descending within the same group, the atomic radius increases and the ionization energy decreases, indicating that the electrons are less attracted to the nucleus and therefore the electronegativity decreases from top to bottom.
Define Acid dissociation constant constant
Answer:
An acid dissociation constant, K a, (also known as acidity constant, or acid-ionization constant) is a quantitative measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction ↽ − − ⇀ − + + known as dissociation in the context of acid–base reactions.
Explanation:
What are the units of measurement for atomic radius?
Answer:
Units used to measure atomic radius:
Angstroms (Å): This the most common unit used. Equivalent to 1.0 x 10-10 meters.
Nanometer (nm): Equivalent to 1.0 x 10-9 meters.
Picometer (pm): Equivalent to 1.0 x 10-12 meters.
What is amplitude in chemisty
Answer:
CHEMISTRY GLOSSARY
Amplitude is the displacement of a wave from zero. The maximum amplitude for a wave is the height of a peak or the depth of a trough, relative to the zero displacement line
what are the steps to go from the names of compounds to the formulas
Answer:
Explanation:
write down the formulas, use the expressions and formulas to convert
PLEASE HELP ASAP!!!! 15PTS
How are 2,2-butanediol and 2,3,4-pentanetriol similar? Pick two.
EXPLANATION
2,2-butanediol is a four carbon chain with two hydroxyl groups both on the second carbon. 2,3,4-pentanetriol is a five carbon chain with three hydroxyl groups; one on carbon 2,3 and 4.
SELECT ALL THAT APPLY
Neither contain a hydroxyl group on an end chain carbon.
Neither contain four carbons in the parent chain.
Both contain a hydroxyl group on the second carbon.
Answer:
Both contain a hydroxyl group on the second carbon.
Neither contain a hydroxyl group on an end chain carbon.
Explanation:
2,2-butanediol Formula: C4H10O2
2,3,4-pentanetriol Formula: C5H12O3
Both contain a hydroxyl group on the second carbon.
Neither contain a hydroxyl group on an end chain carbon.
A compound contains 57.2 percent carbon, 6.1 percent hydrogen, 9.5 percent nitrogen, and 27.2 percent oxygen. What the empirical formula of the compound?
Answer:
So the empirical formula is C14H18N2O5
Explanation:
C = 57.2% = 12g/mol
H = 6.1% = 1g/mol
N = 9.5% = 14g/mol
O = 27.2% = 16g/mol
Empirical Formula for compound hmm
Assume
C = 57.2g
H = 6.1g
N = 9.5g
O = 27.2g
So we have
C = 57.2g/12g = 4.76 moles
H = 6.1g/1g = 6.10 moles
N = 9.5g/14g = 0.68 moles
O = 27.2g/16g = 1.70 moles
Divide each mole value by the smallest number of moles calculated. Round to the nearest whole number.
C = 4.76 moles / 0.68 moles = 7
H = 6.10 moles / 0.68 moles = 9
N = 0.68 moles / 0.68 moles = 1
O = 1.70 moles / 0.68 moles = 2.5
Ok so we now have the ratios but for O it's 2.5, have to be whole numbers so we will need to double all the numbers.
C = 14
H = 18
N = 2
O = 5
So the empirical formula is C14H18N2O5
Which of the following changes depending on the strength of the gravity
field it is in?
A. None of these
B. Mass
C. Matter
D. Weight
Reset Selection
Answer:
D. Weight
Explanation:
Answer:
Weight
Explanation:
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