To solve this question we need to know the concept behind half life. Decay of radioactive element always comes under first order kinetics. Three half-lives have passed since the rock formed.
What is half life?Half life tells about the time at which the radioactive material decays to half of its initial concentration.
Mathematically the the total number of half life can be calculated as
[tex]\rm \frac{t}{t_{1/2}} =-\frac{ln\frac{N_{t}}{N_{0}} }{ln 2}[/tex]
Nt= amount of the isotope that has not yet decayed after a time t
N₀= initial amount of the isotope
t=the time
[tex]t_{1/2}[/tex] = the half-life
Substituting the given values in the above equation
[tex]\rm \frac{t}{t_{1/2}} =-\frac{ln\frac{125}{100} }{ln 2}[/tex]
Solving this we get
3[tex]t_[1/2}[/tex]= t
Therefore, three half-lives have passed since the rock formed.
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Which two elements do not have a second energy level at all?
The two elements that do not have a second energy levels are Hydrogen (H) and Helium (He)
Energy levels are nothing but the 3-D spaces around the nucleus of an atom. The electrons revolve around the nucleus in their respective energy levels. Each energy levels can accommodate only a particular number of electrons.
For example, first energy level can accommodate only a maximum of 2 electrons whereas second energy level can accommodate 8 electrons.
Hydrogen has 1 electron and helium has 2 electrons around their respective nucleus. In both hydrogen and helium, electrons are accommodated in the first energy level.
Hence, the two elements that do not have a second energy levels are Hydrogen (H) and Helium (He)
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A physical model of a crime scene is called
O a map
O an animation
O a reenactment
O a reconstruction
A physical model of a crime scene is called an animation
What exactly is tangible proof at a crime scene?The evidence that crime scene investigators gather includes fingerprints, tyre tracks, hairs, fibres, blood, and other bodily fluids. The NIJ sponsors initiatives to enhance: Blood and other bodily fluids at the location were identified.
There are three different sorts of imprint evidence: bite marks, tool marks, and shoe and tyre prints. Each of these may employ one or more of the following collection strategies, such as taking photos, lifting objects with tape, or plaster-casting.
Physical evidence, also known as actual evidence or material evidence, is any tangible thing that is presented as evidence in a court case that has some connection to the issue that gave birth to the dispute.
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Answer:
The answer is O a reconstruction.
Explanation:
Got it right on the test.
Two solutions are made by mixing sugar and enough water to make a 1 liter solution. One contains 10% sugar and the other 20% sugar. Which solution has more solvent?.
Two solutions are made by mixing sugar and enough water to make a 1 liter solution. 10% sugar has more solvent.
In chemistry, a solution is a homogeneous mixture of two or more compounds in their relative proportions that can be continually altered up to what is referred to as the limit of solubility. Although the word "solution" is frequently used to refer to the liquid state of matter, solutions of gases and solids are also possible. A solute is dissolved by a solvent (s), which is a substance (from the Latin solv, "loosen, untie, solve,") to produce a solution. The most common form of a solvent is a liquid, although other forms include solids, gases, and supercritical fluids. Depending on the temperature, a different amount of solute can dissolve in a given volume of solvent. Solvents are extensively utilized in paints, paint removers, inks, and dry cleaning.
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suppose, in an experiment to determine the amount of sodium hypochlorite in bleach, you titrated a 23.92 ml 23.92 ml sample of 0.0100 m k i o 3 0.0100 m kiox3 with a solution of n a 2 s 2 o 3 nax2sx2ox3 of unknown concentration. the endpoint was observed to occur at 13.80 ml 13.80 ml . how many moles of k i o 3 kiox3 were titrated?
The number of moles of k I o 3 kiox3 titrated is 2.392 x 10^-4 mol.
Concentration is the abundance of a constituent divided with the aid of the total quantity of a combination. Numerous sorts of mathematical descriptions may be prominent: mass concentration, molar concentration, number awareness, and volume awareness.
Concentration is a totally common idea used in chemistry and related fields. it is the measure of ways much of a given substance there is mixed with another substance.
Given : concentration of KIO3 = 0.0100 M
volume of KIO3 = 23.92 mL = 0.02392 L
moles of KIO3 titrated = (concentration of KIO3) * (volume of KIO3 in Liters)
moles of KIO3 titrated = (0.0100 M) * (0.02392 L)
moles of KIO3 titrated = 2.392 x 10^-4 mol
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The photo of a glass of water shows the most abundant substance of earths surface. Which fact about this substance tells you it is a compound
Water is the most abundant substance in earth. Water is a compound because it made of a number of H₂O molecules. Water is a homogeneous compound.
What is compounds?Compounds are substances formed by chemical bonding of two or more elements. All the molecules in the compounds will be identical. For example CO₂ where one carbon and two oxygens covalently bond together to form the compound.
Each compound is made of a number of molecules. Thus molecules are the basic units of compounds like we say as for atoms for every substances.
There are different types of compounds based on the type of bond and number of atoms etc namely ionic compounds, covalent compounds, coordination compounds etc.
Water contains two hydrogen atoms and one oxygen thus forms one molecule of water. Similar kinds of molecules joins together to form the compound.
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Identify the element symbol
1s22s22p63s23p64s23d104p65s24d5
Answer:
Tc
Explanation:
You just have to follow the rows with the exponents. Just remember that when we get to d, the number in the front is a period lower. Hope this helps!
an insulated tank is divided by a thin partition. (a) on the left is 0.79 mole of n2 at 1 bar and 298 k; on the right is 0.21 mole of o2 at 1 bar and 298 k. the partition ruptures. what is dsuniv for the process? (b) on the left is 0.79 mole of n2 at 2 bar and 298 k; on the righ
The entropy is -3.65 and -0.049 J per kelvin per mole respectively are the entropy of an insulated tank.
Entropy is a measure of randomness in a system. It is a state function. It can be denoted by heat supplied for a reversible system per temperature.
The final pressure will be the partial pressure of each gas in the mixture.
a) Partial pressure of nitrogen = mole fraction of nitrogen x total pressure = (0.79 mol) × (1 + 1 bar)/(0.79 + 0.29 mol) = 1.46 bar
Partial pressure of oxygen = mole fraction of oxygen x total pressure = (0.29 mol) ×(1 + 1 bar)/(0.79 + 0.29 mol) = 0.54 bar
Therefore,
ΔS of nitrogen= -R ln1.46 = -0. 38R
∆S of oxygen= -R ln 0.54= -0. 61R
ΔSuniv=−(0.79mol/0.79+0.29mol)×0.38 R−(0.29mol/0.79+0.29mol)×0.61
R=−0.27 R−0.16
R=−0.44
R=−3.65JK−1mol−1
(b) Partial pressure of nitrogen = mole fraction of nitrogen x total pressure = (0.79 mol) × (2 + 1 bar)/(0.79 + 0.29 mol) = 2.19 bar
Partial pressure of oxygen = mole fraction of oxygen x total pressure = (0.29 mol) × (2 + 1 bar)/(0.79 + 0.29 mol) = 0.80 bar
ΔS of nitrogen gas=−Rln1.46=−0.09R
ΔSof sulphur oxide =−Rln0.54=0.22R
ΔSuniv=−(0.79mol/0.79+0.29mol)×0.09R+(0.29mol/0.79+0.29mol)×0.22
R=−0.066 R+0.060
R=−0.049JK−1mol−1
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Put the following elements in order, with the element having the most valence electrons at the top of your list and the element with the fewest valence electrons at the bottom.swap_vertAstatine (At)swap_vertArsenic (As)swap_vertCalcium (Ca)swap_vertSodium (Na)swap_vertOxygen (O)swap_vertSilicon (Si)swap_vertAluminum (Al)
answer
1. Neon
2. Astatine
3. oxygen
4. Arsenic
5. Silicone
6. Aluminium
7. Calcium
8. Sodium
Explain how to make one liter of a 1.25 N sodium hydroxide solution.
Answer:
1.25 moles(N) of NaOH are present in 1000 gm of water.
and 1000gm = 1L
hence we need to put 1.25 Moles (N) of NaOH in 1L H2Owhich part of your brain most likely works hardest
Answer:
The Stroop effect is a simple phenomenon that reveals a lot about how the how the brain processes information.
Answer: The Cerebral Cortex
Explanation: Most information processing takes place here!
what methods are used to address acid mine drainage? burying mine tailings or immersing them in water removing the sulfuric acid before processing the ore adding buffering compounds to neutralize acids exposing the mine tailings to oxygen and sulfur crushing granite to produce silicon dioxide
Adding buffering compounds to neutralize acids is used to address acid mine drainage.
Therefore, the correct option is C.
Adding lime or other alkaline materials to neutralize the acidity of the soil, as well as adding uncontaminated topsoil, planting vegetation, and modifying slopes to stabilize the soil and reduce surface water infiltration into the underlying contaminated material, are some of the common methods for cleaning up contaminated land. The most commonly used technique for treating AMD contamination is the use of alkaline reagents like lime, limestone, sodium carbonate, or sodium hydroxide. The purpose of this process is to neutralize acidic water and prevent the precipitation of heavy metals.
Acid mine drainage (AMD) is a global problem that has negative effects on the ecosystem. Because of its high acidity and high concentration of heavy metals and metalloids, AMD is harmful to both plants and animals as well as to people. Traditional AMD therapies have been in use for a very long time.
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Five liters of hydrogen gas are stored at a pressure of 400
torr. If the temperature does not change, what will be the
volume of the gas when the pressure is decreased to 250
torr?
Five liters of hydrogen gas are stored at a pressure of 400 torrs. If the temperature does not change, then the volume of the gas would be 8 liters when the pressure is decreased to 250 torrs.
What is an ideal gas?It is an imaginary gas for which the volume occupies by it is negligible, this gas does not exist in a practical situation and the concept of an ideal gas is only the theoretical one,
Using the Boyle's law for the given problem,
P₁V₁=P₂V₂
400 × 5 = 250 × V₂
V₂ = 400 × 5 / 250
= 8 Litres
Thus, if the temperature does not change the volume of the gas would be 8 Litres.
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What type of force would put the soccer ball in motion?
balanced
unbalanced
input
output
Type of force would put the soccer ball in motion is unbalanced force.
Unbalanced force is defined as when the net force acting on the object is not equal to zero. The unbalanced force brings an object in motion. while balanced force acting on any object does not change the state of rest or uniform motion. The soccer ball moves from one place to another because unbalanced forces are acting on the soccer ball. this means the resultant force acting on soccer ball is not equal to zero.
Thus, Type of force would put the soccer ball in motion is unbalanced force.
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Answer:
b) Unbalanced force
Explanation:
Unbalanced force is the type of force which puts the soccer ball in motion while kicking it. Hence, option (b) is the correct answer.
What is the mass of 5.36 mol of ammonia
vapor (NH3)?
Answer in units of g.
Answer:
91.12 gram
Explanation:
Number of moles of Ammonia = 5.36
Molecular Mass of Ammonia = 14 + 3 × 1 = 17 gram/mol
Mass = Number of moles × Molecular mass
Mass = 5.36 mol × 17 gram/mol = 91.12 gram
copper has two stable isotopes,and , with masses of 62.939598 amu and 64.927793 amu, respectively. calculate the percent abundances of these isotopes of copper.
Considering the definition of atomic mass, isotopes and atomic mass of an element, the isotope with masses of 62.939598 amu and 64.927793 amu have percent abundances of 69.80% and 30.20% respectively.
Definition of atomic massThe atomic mass (A) is obtained by adding the number of protons and neutrons in a given nucleus of a chemical element.
Definition of isotopeThe same chemical element can have the same atomic numbers, but the number of neutrons is different. These atoms are called isotopes of the element.
Definition of atomic massThe atomic mass of an element is the weighted average mass of its natural isotopes, taking into account the relative abundance of each of them.
Atomic mass of the element in this caseIn this case, you know:
The first isotope has an atomic mass of 62.939598 amu and a percent natural abundance of x%. The second isotope has an atomic mass of 64.927793 amu and a percent natural abundance of (100 -x)%.Average mass of copper is 63.54 amu.The percent abundance can be calculated as:
62.939598 amu× (x%÷100%) + 64.927793 amu× [(100-x)%÷100%]= 63.54 amu
Solving:
62.939598 amu× x+ 64.927793 amu× (1-x)= 63.54 amu
62.939598 amu× x+ 64.927793 amu× 1- 64.927793 amu× x= 63.54 amu
62.939598 amu× x- 64.927793 amu× x= 63.54 amu - 64.927793 amu× 1
-1.988195 amu× x= -1.387793 amu
x= (-1.387793 amu)÷ (-1.988195 amu)
x= 0.6980= 69.80%
Then, (100-x)%= (100 -69.80)%= 30.2%
Finally, the isotope with mass of 62.939598 amu has a percent abundance of 69.80% and the isotope with mass of 64.927793 amu has a percent abundance of 30.20%.
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3. An object that has a volume of 2500 cm³ is dropped into a vat of corn syrup. What is the buoyant force on the object? (The density of corn syrup is 1.38 g/cm³.)
Answer:3.381 X 10^(-11)
Explanation:
The formula for buoyant force is F = -Volume*density*gravitational acceleration. Convert volume and density to SI units and then apply them in the formula where gravitational acceleration is 9.8m/s^2. Done
a reaction involving acetic acid has an enthalpy change of 55.7 kj/mol. what is the concentration of 27.90-ml of this acetic acid solution if the reaction it is involved in evolves 716.12-j of heat?
not gon find it here cuh
Explanation:
The concentration of the acetic acid solution is approximately 0.0128 mol/L, given the information provided.
To determine the concentration of the acetic acid solution, we need to use the given enthalpy change and the heat evolved in the reaction.
The enthalpy change (ΔH) is given as 55.7 kJ/mol, which represents the heat released or absorbed per mole of acetic acid involved in the reaction.
The heat evolved in the reaction is given as 716.12 J. However, we need to convert it to kilojoules to match the unit of the enthalpy change. There are 1000 J in 1 kJ, so 716.12 J is equal to 0.71612 kJ.
Now, we can set up a proportion to find the concentration of the acetic acid solution. The heat evolved is directly proportional to the moles of acetic acid involved in the reaction, which is in turn proportional to the concentration of the solution.
Let's assume the concentration of the acetic acid solution is c mol/L.
The proportion can be set up as:
ΔH (kJ/mol) / Heat evolved (kJ) = 1 mol / c L
Substituting the values we have:
55.7 kJ/mol / 0.71612 kJ = 1 mol / c L
Simplifying:
c = 1 mol / (55.7 kJ/0.71612 kJ)
c ≈ 0.0128 mol/L
Therefore, the concentration of the acetic acid solution is approximately 0.0128 mol/L, given the information provided.
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what are some shared properties of both transition metals and alkali metals.
Both transition metals and alkali metals are good conductors of heat and electricity, react with water, and are easily oxidized.
What are alkali metals and transition metals?The alkali metals are elements of group 1 which are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). They are also known as the s-block elements because they have their outermost electron in an s-orbital.
The alkali metals are shiny, soft, highly reactive metals and readily lose their outermost electron to create cations with charge +1. They can tarnish rapidly in the air due to oxidation by atmospheric moisture and oxygen.
Transition elements or transition metals are elements that have partially filled d-orbitals. An element having a d-subshell that is partially filled with electrons or can form stable cations with an incompletely filled d orbital.
Any element present in the d-block of the modern periodic table which consists of groups 3 to 12, is considered to be a transition element. For example, the mercury in the +2 oxidation state, corresponds to an electronic configuration of (n-1)d¹⁰. Many paramagnetic compounds are formed by transition metals because they have unpaired electrons in the d orbital.
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What are different types of forces and how do they act on objects?