In radioactivity, half-life refers to the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay. If the half-life is 1 000 years, which of the following alternatives is the best approximation of the time, when 7/8 of nuclei have decayed and 1/8 are remaining?In radioactivity, half-life refers to the interval of time required for one-half of the atomic nuclei of a
radioactive sample to decay. If the half-life is 1 000 years, which of the following alternatives is the
best approximation of the time, when 7/8 of nuclei have decayed and 1/8 are remaining?
In radioactivity, half-life refers to the interval of time required for one-half of the atomic nuclei of a
radioactive sample to decay. If the half-life is 1 000 years, which of the following alternatives is the
best approximation of the time, when 7/8 of nuclei have decayed and 1/8 are remaining?
Answers
The best option would be that If the half-life is 1 000 years, then the time when 7/8 of nuclei have decayed and 1/8 are remaining is approximately 2,000 years.
What is radioactivity?Radioactivity is the phenomenon in which an atomic nucleus undergoes spontaneous decay, emitting particles and radiation in the process. This results in the emission of alpha particles (helium nuclei), beta particles (electrons), and gamma rays (high-energy photons), which can be harmful to living things.
The decay process is caused by an unstable ratio of protons to neutrons in the nucleus, leading to the emission of particles and radiation until a more stable configuration is reached.
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Related Questions
describe how lyophobic sols are synthesize by dispersion method
Answers
Explanation:
For preparing lyophobic sol, the substance in bulk is broken down into particles of colloidal dimensions (Dispersion) or aggregating smaller particles into particles of colloidal dimensions (condensation).
A 12.2 mL sample of liquid was found to have a mass of 10.4 g. Calculate the density of this liquid ( in g/mL).
Answers
Answer:
d=m/
Explanation:
d is density, m is mass, v is volume
Given: m =10.4g, v=12.2mL
substituting in equation,
d=10.4/ 12.2
d=0.8524g/mL
To learn more about density:
The density of the liquid is 0.852 g/mL.
To calculate the density of the liquid, we need to use the formula:
Density = Mass / Volume
Given that the mass of the liquid is 10.4 g and the volume is 12.2 mL, we can substitute these values into the formula:
Density = 10.4 g / 12.2 mL
Simplifying this expression, we find:
Density = 0.852 g/mL
Density is a physical property of a substance and is defined as the amount of mass per unit volume. In this case, the density tells us that for every milliliter of the liquid, there is 0.852 grams of mass. The units of grams per milliliter (g/mL) indicate that the density is a ratio of mass to volume.It is important to note that the density of a substance can vary with temperature, so this value is only valid under the conditions at which the measurement was made. Additionally, the density can provide valuable information about the identity of a substance, as different substances have different densities.
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A small amount of aluminum reacts with hydrochloric acid (HCI) to form hydrogen gas and aluminum chloride Write and balance the equation, and how many grams of AI are required to produce 0.10 grams of H2?
Answers
2.007grams
Explanations:The balanced reaction between aluminium and hydrochloric acid is given as:
\(2Al+6HCl\rightarrow3H_2+2AlCl_3\)Determine the moles of Hydrogen gas
\(\begin{gathered} mole=\frac{mass}{molar\text{ mass}} \\ mole=\frac{0.10}{2.016} \\ mole=0.0496mole\text{ of }H_2 \end{gathered}\)According to stoichiometry, 2 moles of Aluminium produces hydrogen 3 moles of hydrogen:
\(\begin{gathered} moles\text{ }of\text{ }Al=00496mole\times\frac{3}{2} \\ moles\text{ of Al}=0.07441mole \end{gathered}\)
Determine the mass of Aluminium
\(\begin{gathered} Mass\text{ of Al}=mole\times molar\text{ mass} \\ Mass\text{ of Al}=0.7441\times\frac{26.98g}{mol} \\ Mass\text{ of Al}=2.007grams \\ \end{gathered}\)Hence the mass of Al required to produce 0.10grams of H2 is 2.007grams
PLEASE HELP 30 POINTS PLS PLS
Answers
23- they are metals
24-Atoms of group 1 elements all have one electron in their outer shell. This means Na and K have the same valence electrons.
25-Metals are solids at room temperature, therefore Na and K are solid.
26- mass number=A=235
Protons=z=92
Neutrons=mass number-protons
Neutrons=A-Z
Neutrons=235-92
Neutrons=143
Why are numbers placed before the elements and molecules in a chemical equation?
A: To represent if an element or molecule is a liquid, gas, or solid.
B: To balance the equation so that it has the same number of atoms of each element on each side.
C: To show whether a substance is an element or molecule.
D: To make sure there's always more reactants than products.
Answers
Numbers are placed before the elements and molecules in a chemical equation so as to balance the equation so that it has the same number of atoms of each element on each side and s denoted as option B.
What is an Equation?This is referred to as a symbolic representation of a chemical reaction and it contains the reactants and products in it thereby providing more information.
It has numbers in front of them so as to make the equation balance as the number of atoms of elements on the reactant side must be equal to that on the product side.
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What is the most highly populated rotational level of Cl2 (i) 25deg C and (ii) 100 deg C? Take B=0.244cm-1.This question should not be resubmitted, it is a textbook question from the Atkins physical chemistry txtbook. 10 e.
Answers
Answer:
i
\(J_{m} = 20 \)
ii
\(J_{m} = 22.5 \)
Explanation:
From the question we are told that
The first temperatures is \(T_1 = 25^oC = 25 +273 =298 \ K\)
The second temperature is \(T_2 = 100^oC = 100 +273 = 373 \ K\)
Generally the equation for the most highly populated rotational energy level is mathematically represented as
\(J_{m} = [ \frac{RT}{2B}] ^{\frac{1}{2} } - \frac{1}{2}\)
Here R is the gas constant with value \(R =8.314 \ J\cdot K^{-1} \cdot mol^{-1}\)
Also
B is given as \(B=\ 0.244 \ cm^{-1}\)
Generally the energy require per mole to move 1 cm is 12 J /mole
So \(0.244 \ cm^{-1}\) will require x J/mole
\(x = 0.244 * 12\)
=> \(x = 2.928 \ J/mol \)
So at the first temperature
\(J_{m} = [ \frac{8.314 * 298 }{2* 2.928 }] ^{\frac{1}{2} } - 0.5 \)
=> \(J_{m} = 20 \)
So at the second temperature
\(J_{m} = [ \frac{8.314 * 373 }{2* 2.928 }] ^{\frac{1}{2} } - 0.5 \)
=> \(J_{m} = 22.5 \)
Mass = 7.2 g Volume = 3 mL Density = ?
Answers
Answer:
2.4
Explanation:
The following data was collected when a reaction was performed experimentally in the laboratory. Reaction Data Reactants Products Fe2O3 Al Al2O3 Fe Starting Amount in Reaction 3 moles 5 moles ? ? Determine the maximum amount of Fe that was produced during the experiment. Explain how you determined this amount.
Answers
The maximum amount, in grams, of Fe that would be produced during the experiment, will be 280 grams
Sotichiometric calculationFrom the equation of the reaction:
\(Fe_2O_3 + 2Al -- > 2Fe + Al_2O_3\)
The mole ratio of \(Fe_2O_3\) to Al is 1:2.
But 3 moles and 5 moles of reactants respectively started the reaction. Thus, Al is limited in availability and will determine the amount of products that will be produced.
The mole ratio of Al and Fe is 1:1, therefore, a maximum of 5 moles of Fe will be produced from the reaction.
5 moles Fe = 5 x 56 = 280 grams
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In the following reaction how many moles of NaCI are needed to produce 5.4 miles of Na2O
NaCI+MgO= Na2O+MgCI2
Answers
To produce 5.4 moles of \(Na_{2} O\) in the given reaction, 10.8 moles of NaCl are required.
The given chemical equation is a balanced equation, which means it represents the stoichiometric relationship between the reactants and products involved in the reaction.
The coefficients of the balanced equation represent the number of moles of each reactant and product involved in the reaction.
In this case, the equation is:
2 NaCl + MgO → \(Na_{2} O\) + \(MgCl_{2}\)
From the equation, we can see that 2 moles of NaCl are required to produce 1 mole of . Therefore, to produce 5.4 moles of \(Na_{2} O\), we need to use stoichiometry to determine the amount of NaCl required.
We can use the following formula to calculate the number of moles of NaCl required:
moles of NaCl = moles of \(Na_{2} O\) × (2 moles NaCl / 1 mole \(Na_{2} O\))
Substituting the given values, we get:
moles of NaCl = 5.4 moles \(Na_{2} O\) × (2 moles NaCl / 1 mole \(Na_{2} O\)) = 10.8 moles NaCl
Therefore, we need 10.8 moles of NaCl to produce 5.4 moles of \(Na_{2} O\) in the given reaction.
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need help with this question
Answers
Answer:
Sugar, Carbon Dioxide, And Water
Explanation:
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., without breaking chemical bonds. Chemical substances can be simple substances, chemical compounds, or alloys. Chemical elements may or may not be included in the definition, depending on expert viewpoint.
1. Consider the following reaction where Kc = 1.29×10-2 at 600 K.
COCl2(g) CO(g) + Cl2(g)
A reaction mixture was found to contain 9.87×10-2 moles of COCl2(g), 2.19×10-2 moles of CO(g), and 3.79×10-2 moles of Cl2(g), in a 1.00 liter container.
Is the reaction at equilibrium?
If not, what direction must it run in order to reach equilibrium?
The reaction quotient, Qc, equals _____
The reaction:
A. must run in the forward direction to reach equilibrium.
B. must run in the reverse direction to reach equilibrium.
C. is at equilibrium.
2. Consider the following reaction where Kc = 55.6 at 698 K.
H2(g) + I2(g) 2HI(g)
A reaction mixture was found to contain 2.59×10-2 moles of H2(g), 4.38×10-2 moles of I2(g) and 0.294 moles of HI(g), in a 1.00 liter container.
Is the reaction at equilibrium?
If not, what direction must it run in order to reach equilibrium?
The reaction quotient, Qc, equals ____
The reaction:
A. must run in the forward direction to reach equilibrium.
B. must run in the reverse direction to reach equilibrium.
C. is at equilibrium.
Answers
Answer:
Consider the following reaction where Kc = 1.29×10-2 at 600 K:
COCl2(g) <=> CO(g) + Cl2(g)
A reaction mixture was found to contain 9.85×10-2 moles of COCl2(g), 2.61×10-2moles of CO(g), and 3.71×10-2 moles of Cl2(g), in a 1.00 Liter container.
Indicated true (T) or false (F) for each of the following:
Describe what is meant by synthesis. How do the functions of analysis, synthesis, and evaluation relate to each other
Answers
Answer:
New element formed by combination of reactants.
Explanation:
Synthesis refers to the production of a new product from the combination of two or more reactants. Analysis, synthesis, and evaluation are related to each other because in synthesis a new product is formed while in analysis, we examine the structure of the new product in detailed and in evaluation, we assess the quantity of a new product. So analysis and evaluation gives a lot of information about the product which is formed in synthesis.
Which statement best represents the Law of Conservation of Matter with regard to chemical reaction?
Answers
The statement which best represents the Law of Conservation of Matter with regard to chemical reaction is reactants and products have the same number and type of atoms, but the atoms may be recombined.
According to the rule of conservation of mass, matter cannot be generated or destroyed during a reaction. This implies that the mass of each reactant and each product in a reaction will be equal. Although the mass may change forms during the reaction, neither matter creation nor destruction occurs.
In a closed system, matter is conserved, to put it another way. Nothing (gas, water, or other) may enter or leave a closed system. The system contains all of the products. The system cannot accept or reject matter. A closed system could be the entire earth or it could be a tightly enclosed test tube.
The terms "law of conservation of mass" and "law of conservation of matter" are frequently used interchangeably. The law may also go by the titles of the law of mass conservation or the conservation of matter.
Hence, reactants and products have the same number and type of atoms, but the atoms may be recombined- best represents the law of conservation of matter.
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Your question is incomplete please write the complete question over the internet.
17. HAZWOPER training and certification recognizes:
a. A large number (as much as 80%) will self-present or be self-referred victims
b. Awareness level training will promote proper initial triage actions
c.
Victims will use any entrance they can enter at the hospital, in addition to the
emergency department entrance
d. Both A and C
Answers
HAZWOPER training and certification recognize:
a large number (as much as 80%) will self-present or be self-referred victimsVictims will use any entrance they can enter at the hospital, in addition to the emergency department entranceThe correct option is both A and C
What is the HAZWOPER training and certification?HAZWOPER (Hazardous Waste Operations and Emergency Response) training and certification recognize that a large number of victims (as much as 80%) in hazardous waste incidents or emergencies will self-present or be self-referred for medical treatment.
Additionally, HAZWOPER training acknowledges that victims may use any entrance they can access at a hospital, not just the emergency department entrance.
This is because individuals affected by hazardous materials may arrive at different areas of the hospital seeking medical assistance.
Therefore, option d. Both A and C are correct statements regarding the recognition of HAZWOPER training and certification.
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how do you balance this equation
2h2s+3o2+so2
Answers
The balanced equation is: 4 \(H_2S\)+ 3 \(O_2\)→ 4 \(SO_2\)+ 8 \(H_2O\)
The given chemical equation is unbalanced. To balance it, we need to adjust the coefficients in front of each chemical species until the number of atoms on both sides of the equation is equal.
The unbalanced equation is:
2 \(H_2S\)+ 3 \(O_2\)→ \(SO_2\)
Let's start by balancing the sulfur (S) atoms. We have two sulfur atoms on the left side and one sulfur atom on the right side. To balance the sulfur, we can place a coefficient of 2 in front of the \(SO_2\):
2 \(H_2S\)+ 3 \(O_2\)→ 2 \(SO_2\)
Now, let's balance the hydrogen (H) atoms. We have four hydrogen atoms on the left side (2 from each \(H_2S\)) and none on the right side. To balance the hydrogen, we can place a coefficient of 4 in front of the water (H2O) on the right side:
2 \(H_2S\)+ 3 \(O_2\)→ 2 \(SO_2\)+ 4 \(H_2O\)
Finally, let's balance the oxygen (O) atoms. We have six oxygen atoms on the right side (3 from \(O_2\) and 3 from 2 \(SO_2\)) and three on the left side (2 from \(H_2S\)). To balance the oxygen, we can place a coefficient of 3/2 in front of the O2:
2 \(H_2S\)+ (3/2) \(O_2\)→ 2 \(SO_2\)+ 4 \(H_2O\)
To remove the fractional coefficient, we can multiply all coefficients by 2:
4 \(H_2S\) + 3 \(O_2\)→ 4 \(SO_2\)+ 8 \(H_2O\)
Now the equation is balanced, with an equal number of atoms on both sides. The balanced equation is:
4 \(H_2S\)+ 3 \(O_2\)→ 4 \(SO_2\)+ 8 \(H_2O\)
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How much did asbestos exposure decrease during the year 1982 and 1983
Answers
The asbestos exposure during the years 1982 and 1983 was 2.5 fibers per cubic centimeter and 0.8 fibers per cubic centimeter respectively. So asbestos exposure decreased by 1.7 fibers per cubic centimeter during the year 1983.
Breathlessness Persistent, dry cough Chest pain or tightness Lack of a dry, crackling sound in the lungs when you breathe in Wider and rounder fingers and toes are some of the symptoms of asbestos exposure.
The largest group of people exposed to asbestos is those working in the construction industry. Historically, asbestos was also used by pipe fitters and shipyard workers. In addition, asbestos was used by military personnel, auto mechanics, and many other occupations.
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The container seems to have about 650 mL of copper(II) sulfate
solution in volume. Convert this volume to liters (L) of
solution.
Answers
The volume of copper (II) sulfate in a container is equivalent to 0.650L.
How to convert units of volume?Volume is the three-dimensional measure of space that comprises a length, a width and a height. It is measured in units of cubic centimeters (cm³) in metric, cubic inches or cubic feet in English measurement.
According to this question, a container seems to have about 650 mL of copper(II) sulfate solution in volume. The volume can be converted to litres as follows:
1 millilitre = 0.001 litre
650 millilitres = 0.650 litres
Therefore, 0.650L is the volume of copper II sulfate in litres.
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A block of wood that is 3 cm on each side has a mass of 27 g. What is the density of the block? ( using sig figs )
Answers
Answer:
desity =mass /volume
27/ 3cube
1g/cm³
What is the pH of a solution with [H⁺] = 2.5 x 10-4 M?
Answers
Answer:
\(\text{pH}=3.6\)
Explanation:
Given that,
\([H^+]=2.5\times 10^{-4}\ M\)
We need to find the pH of a solution with \([H^+]=2.5\times 10^{-4}\ M\).
We know that,
\(\text{pH}=-\text{log}[H^+]\\\\=-\text{log}[2.5\times 10^{-4}]\\\\=-(-3.6)\\\\=3.6\)
So, the pH of the solution is 3.6.
How many seconds (s) are needed to deposit 7.25 g of copper metal from an aqueous solution of CuCl2, using a current of 3.1 Amps.
Answers
Answer:
7,052.6secs
Explanation:
n of Cu = +2
R.A.M of Cu = 64g
m = 7.25g
I = 3.1A
F = 96500
nF = R.A.M
It = m
2*96500 = 64
3.1*t = 7.25
1,399,250 = 198.4t
t = 7,052.6secs
Balance the chemical equation
Ba3N2 + H2O-----> Ba(OH)2 + NH3
Answers
Answer:
Ba3N2 + 6H2O ------> 3Ba(OH)2 + 2NH3
chlorine reacts with fluorine to form flowing monofluoride write an equation for this reaction including the state symbols are the substances are a room temperature
Answers
Hope this helped
what is the solution
Answers
Answer: 1.85 (D)
Explanation:
D is the solution to this question
HELPPPP FASTTTTTTT
An inflated balloon is left outside overnight. It has a volume of 1.7 4 L when the temperature is 20.2 degC and the pressure is 1.02 atm. At what temperature will the balloon have a volume of 1.56 L if the pressure falls to 0.980 atm?
What gas law will you use to solve this problem?
options
A. boyles gas law
B. charles gas law
C. Gay lussacs gas law
D. combined gas law
E. ideal gas law
What is your reason for choosing the gas law?
options
A.moles are in the problem
B. there are 2 variables that are changing
C. there are 3 variables that are changing
In this problem, is the volume increasing or decreasing?
What is the unknown that you are solving for?
options.
A.T1
B.T2
What temperature will you use in your calculations?
A. 20.2 degc
B. 273 k
C. 293.2 K
What is the final temperature after the volume and pressure decrease in this problem?
options.
A. 253k
B. 314k
C. 353 K
Answers
Explanation:
1.The gas law that we will use to solve this problem is the combined gas law.
2.We will choose the combined gas law because there are three variables that are changing in this problem: volume, pressure, and temperature.
3The volume is decreasing in this problem, from 1.74 L to 1.56 L.
The unknown that we are solving for is T2, the temperature at which the balloon will have a volume of 1.56 L.
4We will use the temperature in Kelvin for our calculations. To convert from Celsius to Kelvin, we add 273.15 to the Celsius temperature. Therefore, the temperature we will use in our calculations is 293.35 K (20.2°C + 273.15).
5To find the final temperature, we can use the combined gas law equation:
(P1 x V1)/T1 = (P2 x V2)/T2
where P1 = 1.02 atm, V1 = 1.74 L, T1 = 293.35 K, P2 = 0.980 atm, and V2 = 1.56 L.
Substituting the values into the equation and solving for T2, we get:
T2 = (P2 x V2 x T1)/(P1 x V1)
= (0.980 atm x 1.56 L x 293.35 K)/(1.02 atm x 1.74 L)
= 268.06 K
Therefore, the final temperature after the volume and pressure decrease is 268.06 K, which is approximately 253 K (option A).
During surgery, a patient receives 3.5 pt of plasma. How many milliliters of plasma were given?
Answers
Answer:
1656.116
Explanation:
473.176 is how many millimetres equals a pint and you would multiply that by 3.5
Plasma is the largest component of blood comprises about 55% of the total blood volume. It is responsible for the maintenance of immune system. 3.5 pt of plasma is equal to 1656.12 milliliters.
How to convert pints to mL?A pint is a measure of volume or capacity. It is a unit in both imperial and US customary measurement system. Traditionally, it is one-eighth of a gallon. To convert pints to mL, a formula can be used.
In US customary measurement system, 473.176 mL of any liquid substance is equal to a pint. To convert pints to milliliters, we can multiply the given value of pints simply by 473.176.
For example, to find how many milliliters of plasma is there in X pints of plasma.
pints to mL formula:
___mL = pint × 473.176
In the question, 3.5 pints of plasma is given. So, to calculate the amount of plasma in milliliters we can use the formula:
3.5 × 473.176 = 1656.116
Therefore, 1656.116 mL of plasma is equal to 3.5 pt which is received by the patient.
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Identify the double displacement reaction
2NH3+H2SO4
Answers
Answer:
......................
nh42so4
ch4+br2 ch3br+hbr which type of reaction does this equation represent
Answers
To solve such this we must know the concept of combination reaction. Therefore, the given reaction CH\(_4\)+Br\(_2\) \(\rightarrow\)CH\(_3\)Br+ HBr is a combination reaction.
What is chemical reaction?Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.
CH\(_4\)+Br\(_2\) \(\rightarrow\)CH\(_3\)Br+ HBr
The above reaction is a combination reaction. In combination reaction, more than one reactant combine to form a product. Because new chemicals are created during combination reactions, they are often referred to as synthesis.
Therefore, the given reaction is a combination reaction.
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Why do we use commas after transition words?
Commas are extra punctuation.
Commas show readers when something should be shouted.
Commas indicate a natural pause in the sentence.
Commas make the sentence look nicer.
Answers
Answer:
C - commas indicate a natural pause in the sentence
GivenL C2H2 + 5O2 ------> 4 CO2 + 2H2O
If 9.5 L of CO2 are produced, how many liters of O2 will be needed for this reaction? Show work
Answers
Answer:
101 L
Explanation:
35.0 g KOH ÷ 56.09 g/mol KOH × (1 mol H2O/ 1 mol KOH) × 18 g/mol H2O = 11.2 g H2O
35.0 g HCl ÷ 36.45 g/mol HCl × (1 mol H2O/ 1 mol HCl) × 18 g/mol H2O = 17.3 g H2O
35.0 g KOH is the limiting reactant
The mass number of Fe2+ is 56. How many neutrons are there in a single Fe2+ atom?
28
30
56
58
Answers
Answer:
A.) 28
Explanation:
The mass number is the number of protons and neutrons within a particular atom. The charge of the atom is irrelevant because the mass number is not affected by the number of electrons.
Unless this atom is an isotope (different number of neutrons), there should be an equal amount of protons and neutrons.
As such, since the mass number is 56, there should be 28 protons and 28 neutrons (56 / 2 = 28).