Therefore if a patient receives a dose with an activity of 53. 8 mCi of technetium-99m for cardiac imaging, radioactivity will be left in the patient’s body 72 hours after injection is 0.00024
The equation that describes the radioactive decay is:
Ln [A] = -kt + Ln [A]₀
Where [A] could be taken as activity of the source after time t, [A]₀ is initial activity and k is decay constant.
Decay constant could be written as:
k = ln2 / Half-life
k = ln 2 / 6h
k = 0.115h⁻¹
Replacing in decay equation:
ln a = -0.115 x 72 + Ln [53.8]
ln a = - 8.28 + 3. 98
ln a = - 8.28
log a = -4/ 2.303
log a = 1.867
Therefore if a patient receives a dose with an activity of 53. 8 mCi of technetium-99m for cardiac imaging. radioactivity will be left in the patient’s body 72 hours after injection is 1.867
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The density of copper is 8.92g/cm³. If a 10.00g sample is placed in a graduated cylinder that
contains 15.0mL of water, what is the total volume?
The total volume of sample with given density and mass of copper is 16.815 cm³.
Equation :volume of copper = mass / density
v = 10.00g / 8.92g/cm³
v = 1.121 cm³
So to calculate total of volume of given sample,
Total volume = Volume of copper x Volume of water
V = 1.121 x 15.0
V = 16.815 cm³
What is volume ?A solid shape's capacity is measured using volume, a three-dimensional quantity. It implies that a closed figure's volume determines how much three-dimensional space it can occupy. A derived unit called the cubic meter (m3) serves as the SI unit of volume. The cubic decimeter is referred to as a "liter" (L) (dm3).
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What is the energy of an electron in the n = 15 energy state?
A.) 4.91 x 10^-16 J
B.) 3.27 x 10^-17 J
C.) -1.45 x 10^-19 J
D.) Zero. The n = 15 energy state doesn't exist.
E.) -9.69 x 10^-21 J
E. The energy of an electron in the n = 15 energy state is determined as -9.6 x 10⁻²¹ J.
Energy of the electron in the n = 15 energy stateThe energy of an electron in the n = 15 energy state is calculated as follows;
E = -13.6/n²
given n = 15
E = -(13.6/15²)
E = -0.06 eV
Energy of the electron in JoulesE = -0.06 x 1.6 x 10⁻¹⁹
E = -9.6 x 10⁻²¹ J
Thus, the energy of an electron in the n = 15 energy state is determined as -9.6 x 10⁻²¹ J.
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What is the molarity of a substance in which 10.8 grams per f calcium chloride is dissolved in enough water to make to make 125 mL of solution?
The moles of solute per liter of solution is measured as molarity. For instance, when table salt is dissolved in water, water serves as both the solution and the solute. Sodium chloride weights 58.44 grams per mole. 58.44 grams of sodium chloride dissolve in one liter of water to form a one molar solution, or 1M.
What is the molarity of a substance in which 10.8 grams per f calcium chloride is dissolved in enough water to make to make 125 mL of solution?
"2.7 moles"
Rearranging Molarity is determined by multiplying moles by litres.
Litres times molarity equals moles.
The amount of water in 125 g is similar to 125 ml, or 0.125 litre.
The number of moles is 0.125 x 2 = 0.25 mol since the molarity is 2.0M.
To get the answer of 10.8g, simply multiply this by the molar mass of calcium chloride, which is 110.98 g/mol.
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What is the density of a metal block that has a mass of 250.00 grams and the length is 16.25 cm, the width is 2.30 cm, and the height is 6.00 cm?
Round to the correct number of significant figures. Do not include the unit in the answer.
The density of a metal block that has a mass of 250.00 grams and the length is 16.25 cm, the width is 2.30 cm, and the height is 6.00 cm is 1.11.
What is density?Density can be defined as the measurement of how tightly a material is pecked together. It is defined as mass per unit volume.
Its SI unit is g/cm3 .
Density can be expressed as
Density = mass/ volume
Volume of metal block = length x width x height
= 16.25 x 2.30 x 6.00
= 224.3 ml
Density = 250.0 / 224.3 g/ml
= 1.11 g/ml
Thus, the density of a metal block that has a mass of 250.00 grams and the length is 16.25 cm, the width is 2.30 cm, and the height is 6.00 cm is 1.11.
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While camping, you make a snack over a campfire. You roast a marshmallow over the campfire until it is browned and put it between some chocolate and graham crackers. When you take a bite, you notice that the chocolate and marshmallow have melted slightly.
Which statement correctly identifies a part of this process as a physical or a chemical change?
A. The melting of the chocolate is a chemical change
B. The digestion of the food is a physical change
C. The toasting of the marshmallow is a chemical change
D. The burning of the wood for the campfire is a physical change
The answer is C. The toasting of the marshmallow is a chemical change.
Why?
Based on the other options:
A.) The melting of the chocolate ISNT a chemical change. It's a physical change.
B.) The digestion of food is NOT a physical change. It's a chemical change.
D. The burning of the wood for the campfire is NOT a physical change. It's a chemical change.
Physical Change: Doesn’t change the composition of the matter. However, its physical appearance and properties can change.
Chemical Change: During chemical changes, the matter that you start with isn’t the matter you end up with.
if you can please answer both
Answer: C & D
Explaination:
C because the atomic number increases sequentially and also the nuclear charge
D because as you're moving down a column the valance electrons does not change, only the atomic radius does.
How I can convert 7 Ms to s
Answer:
Divide the time value by 1000
Explanation:
7 Ms = 0.007s
32. Describe how scientific notation makes it easier to
work with very large or very small numbers.
Scientific notation makes it easier to work with very large or very small numbers because it makes a very small or large number into a shorter one.
How scientific notation makes it easier to work with very large or very small numbers?Scientific notation makes it easy to compare numbers that have very large values because all the zeroes have been replaced with small number which can be read easily. In scientific notation, numbers with a greater exponent are bigger than numbers with a small or less exponent because higher exponent shows the larger value and smaller value represents smaller value. So that's why scientific notation make easier to write or read a very large or small number.
So we can conclude that Scientific notation makes it easier to work with very large or very small numbers because it makes a very small or large number into a shorter one.
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For the reaction shown, identify the oxidation half-reaction and the reduction half-reaction. KNO3 → KNO2 + O₂ Which pair of half-reactions represents the balanced half-reactions? N5+ + 2e →N³+ 0² →0₂ + 4e 2N5+ + 4e¯ → 2N³+ 20²- → 0₂ +4e 4N5+ 2e4N³+ 20² → 20₂ + 4e¯
N5+ + 2e →N³
here Nitrogen gains electron so, its reduction half-reaction
20²- → 0₂
here oxygen loss electron so, its oxidation half-reaction
20² → 20₂ + 4e¯
here oxygen loss electron so, its oxidation half-reaction
2N5+ + 4e¯ → 2N³
here nitrogen gains electron so, its reduction half-reaction
When an atom loses electrons, it is said to be oxidising; when it acquires electrons, it is said to be reduced. A redox reaction occurs when both of these reactions take place at the same time.When a molecule oxidises, it implies it either gives or loses electrons to another molecule. As a result, the reaction between a molecule of oxygen and a molecule of hydrochloric acid may be shown below. Because it has to combine with hydrogen to create a proper molecule, the oxygen molecule in this process is unstable. Four extra hydrogen molecules are available for disposal in the hydrogen chloride molecule. Thus, although the hydrochloric acid transforms into chlorine gas, all of the hydrogen from the acid unites with the oxygen molecule to form water.To know more about oxidation visit : https://brainly.com/question/13003361
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(PLEASE HELP)"The most abundant isotope of Hydrogen has a mass of 1 amu. Therefore, the average atomic mass on the periodic table for Hydrogen will be 1 amu." Using the terms isotopes, abundance, average atomic mass and weighted mass to explain why this misconception is incorrect and why the abundance(amount) of each isotope of the element affect the average atomic mass.
The statement the most abundant isotope of Hydrogen has a mass of 1 amu is wrong.
What is the average atomic mass?The average atomic mass could be obtained as the sum of the products of the percentage abundance of each of the hydrogen isotopes and the mass of the isotope.
We know that every element has isotopes. In every sample of the atom, there are various isotopes of the element. Thus the average atomic mass must take into account the masses of all these isotopes.
As such, the statement the most abundant isotope of Hydrogen has a mass of 1 amu is wrong.
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Will mark BRAINLYEST
When you place your hand in water it appears to be larger. explain why this happens
Answer:
because the water is like a magnified glass Its on your hand and your hand apears bigger
Explanation:
PLEASE HELP ME I AM STRUGGLING SO BADLY ACELLUS
What is the energy of an orange lamp with a frequency of 5.10 x 10^14 Hz
? X 10^? <----- ANSWER LIKE THAN PLEASE
The energy of an orange lamp with a frequency of 5.10 x 10¹⁴ Hz is 5.88 x 10⁻⁷ is 3.38 x 10⁻¹⁹ J.
Frequency is defined as the number occurrences of repeated events per unit of time. SI unit is hertz (Hz).
Using the formula,
E = hν
where,
E = energy in joules (J)
h = Planck's constant = 6.63 x 10⁻³⁴ Js
ν = frequency in hertz
Given :
frequency = 5.10 x 10¹⁴ Hz
h = 6.63 x 10⁻³⁴ Js
Putting the values,
E = (6.63 x 10⁻³⁴) x (5.10 x 10¹⁴) J
E = 3.38 x 10⁻¹⁹ J
Therefore, the energy of an orange lamp with a frequency of 5.10 x 10¹⁴ is 3.38 x 10⁻¹⁹J.
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1000 in² = ? yd.
Could sb help me out
Answer:
um 27 yards..............
Write the name of the alkane with six carbon atoms
Hexane is an alkane with six carbon atoms.
Hexane is an organic substance having the chemical formula C6H14. It is a straight-chain alkane containing six carbon atoms. When pure, it is an odorless, colourless liquid with a boiling point of roughly 69 °C (156 °F). It is a broadly applicable non-polar solvent that is quite safe, mainly unreactive, affordable, and easily evaporable.
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Given that the work function of chromium is 4.40 eV calculate the kinetic energy of electrons emitted from chromium surface that is irradiated with ultraviolet radiation of wavelength 200.0 nm.
The kinetic energy of electrons emitted from chromium surface is determined as 2.9 x 10⁻¹⁹ J.
Energy of the emitted photon
The energy of the emitted photon is calculated as follows;
E = hf
E = hc/λ
where;
h is Planck's constantc is speed of lightλ is wavelength of the photonE = (6.626 x 10⁻³⁴ x 3 x 10⁸) / (200 x 10⁻⁹)
E = 9.94 x 10⁻¹⁹ J
Work function of the chromium is joulesΦ = 4.4 x 1.6 x 10⁻¹⁹
Φ = 7.04 x 10⁻¹⁹ J
Kinetic energy of the electronE = K.E + Φ
K.E = E - Φ
K.E = 9.94 x 10⁻¹⁹ J - 7.04 x 10⁻¹⁹ J
K.E = 2.9 x 10⁻¹⁹ J
Thus, the kinetic energy of electrons emitted from chromium surface is determined as 2.9 x 10⁻¹⁹ J.
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Which reactions performed in the experiment
involved chemical changes?
crushing calcium carbonate
mixing calcium carbonate and HCI
boiling water
heating copper (II) sulfate pentahydrate
separating iron filing and sulfur
mixing potassium iodide and lead nitrate
combining magnesium and HCI
burning the candle
DONE
Mixing calcium carbonate and HCl
Heating copper sulfate pentahydrate
Mixing potassium iodide and lead nitrate
Combining magnesium and HCl
Burning the candle.
The crushing of limestone is a bodily trade it no longer alters the chemical composition of the limestone. The heating of limestone is a chemical trade the limestone decomposes into two other materials, lime and carbon dioxide. both ended in gas formation. both ended in shade change.
Rust is not anything however Iron Oxide is a brand new substance shaped out of the response. The color of the floor of the iron additionally modifications. hence, rusting of iron is a chemical trade. Rusting is an instance of chemical exchange. A chemical property describes the ability of a substance to go through a particular chemical alternate. The chemical belonging of iron is that it is miles capable of combining with oxygen to form iron oxide, the chemical call of rust. like several steel carbonates, calcium carbonate reacts with acidic solutions to supply carbon dioxide gas.
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Marjorie is trying to determine the identity of an unknown substance. After running tests, she determines that the substance is insoluble in CCl4 with a density of about 2.2 g/mL. Substance Density Boiling Point Solubility (in water) Solubility (in CCl4) NaCl 2.165 g/mL 1413°C soluble insoluble C10H8 1.14 g/mL 255°C insoluble soluble FeCl3 2.898 g/mL 315°C soluble insoluble SiO2 2.634 g/mL 2590°C insoluble insoluble Using the data above, which of the following substances is most likely Marjorie's unknown? A. FeCl3 B. NaCl C. SiO2 D. C10H8
Marjorie's unknown substance is sodium chloride NaCl.
The substance is insoluble in CCl₄. The density of the substance is 2.2 g/mL.
Solubility:
The fact that the chemical is insoluble in CCl₄ (tetrachloromethane), as indicated in the statement, indicates that the substance is polar in nature. Only C₁₀H₈ of the choices is soluble in CCl₄ since they are both non-polar by nature and related substances dissolve similarly. C₁₀H₈ is therefore disregarded.
Density:
There are now only three possibilities left. SiO₂, FeCl₃, and NaCl. The student discovered that the material has a density of 2.20 g/ ml. This is quite similar to sodium chloride's density (i.e., 2.165 g/mL). As a result, sodium chloride is most likely the material the student is working with.
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Pb + PbO2 + 2H2SO4 → 2PbSO4 + 2H2O
What is the mole ratio of PbO2 to water
The mole ratio of PbO2 to water is 1:2.
The mole ratio of PbO2 to water, PbO2:H2O, is 1:2 when the reaction stoichiometry is taken into consideration.
The appropriate reaction is:
2 PbSO4 + 2 H2O ⇒ Pb + PbO2 + 2 H2SO4
The following numbers of moles of each component are involved in the reaction according to reaction stoichiometry, which describes the relationship between the amounts of reagents and products in a chemical reaction:
1 mole Pb
1 mole of PbO2
H2SO4: 2 mol
2 moles of PbSO4
Water: 2 moles
Then, you can see that according to the reaction's stoichiometry, 1 mole of PbO2 produces 2 moles of water (H2O).
Therefore,the mole ratio of PbO2 to water is 1:2.
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Why can’t calcium ,CA, be broken down into a simpler substance?
A 25 mL sample of matter has a density of 7.9 g/ml., What is the mass of the substance?
Answer:
197.5 grams
Explanation:
To find the mass (g) of the sample, you need to multiply the given volume (mL) by the denisty. You can use the denisty to convert between mL and g because the denisty is a ratio which represents the mass of the sample per every 1 mL. The ratio should be arranged in a way that allows for the cancellation of units (mL should be in the denominator).
Denisty = 7.9 grams/ 1 mL
25 mL 7.9 grams
----------------- x ---------------------- = 197.5 grams
1 mL
**The final answer is not written with the proper sig figs.
72. A 5-mL sample of water has a mass of 5g. What is the density of water?
Answer: 1 g/ml
Explanation:
5 g / 5ml= 1 g/ml
3. In a chemical reaction, the final amount of the products is determined by the
A. Universal Gas Law
B. catalysts involved
C. air pressure
D. temperature
E. limiting reactant
Which subatomic particle is used to identify the atom, as it never changes?
Protons
Electrons
Neutrons
Nucleus
What is the volume of foil for 14.45cm times 8.55 cm times 0.550 g
The volume of foil for 14.45cm times 8.55 cm times 0.550 g is
67.95 cm^3
Volume = lenght * breadth * height
= 14.45cm * 8.55 cm * 0.550 cm
= 67.95 cm^3
Volume is the amount of space an object take upA measure of the size of a body or region in three-dimensional space.amount of space occupied by an object L x W x Hcubic centimeters is the basic unit for measuring the volume of solids and gasesvolume is a Three Dimensional existing in three dimensions; having length, width, and height.Cubic Yard is the volume of a cube is one yard on each side.Cubic Meter is the volume of a cube is one meter on each side.To know more about Volume visit :
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state the types of matter
Answer:
they're
Explanation:
solid, liquid and gas
One example of an estuary is
Responses
A The Atlantic Ocean.the Atlantic Ocean.
B Lake Superior.Lake Superior.
C the Potomac River.the Potomac River.
D the Chesapeake Bay.
NO SPAMS OR I WILL REPORT YOU AND BAN YOU IMMEDIATLEY
Answer: D I PROMISE
Explanation:
IVE TOOK THE TEST AND ITS D
Round the answer of the following calculation to the correct number of significant figures;
3700 20.1 x 5.60 x 0.0407
The calculation gives the product 17000 to 2 significant figures
What are significant figures in a calculation?Significant figures in a calculation or a number refers to the number of non-zero numbers that are present in a number.
If the number contains a decimal point, the number of non-zero numbers before the decimal point gives the number of significant figures.
However, if a zero occurs between non-zero numbers, it is considered significant.
Significant figures are used in approximation to indicate to what point a set of numbers become significant.
In a calculation, the number significant figure is determined by the number which has the lowest number of significant figures.
In the given calculation, the lowest significant figure is in the numbers 3700 and 5.60
3700 × 20.1 × 5.60 × 0.0407 = 17000 to 2 significant figures
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How many moles of ethylenediamine (H2NCH2CH2NH2) are contained in 10.4 ml of 25% ethylenediamine solutions? The density of the solution is 0.950 g/mL.
Moles of ethylenediamine contained in 10.4 ml of 25% ethylenediamine solutions is 0.0388 moles
What is mole?
A mole is defined as 6.02214076 × 10²³ of some chemical unit, be it atoms, molecules, ions, or others.
Given:
volume=9.8 mL
Density= 0.960 g/mL
Percent concentration of solution= 25%
mass of nickel chloride=1.85 g
mass = density * volume
mass = 0.950 g/ml * 9.8 ml
mass = 9.31g
Since it is a 25 % solution of Ethylenediamine
mass of ethylenediamine in 25 moles
moles of ethylenediamine = [tex]\frac{2.33g}{60g/mol}[/tex] =0.0388 moles
Thus, Moles of ethylenediamine contained in 10.4 ml of 25% ethylenediamine solutions is 0.0388 moles.
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2.5 g Ti, 1.7 g F2
Express your answer using two significant figures
The theoretical yield of titanium tetrafluoride is 2.79 g
What is the theoretical yield?We know that the theoretical yield is the yield of the product that we can obtain from the stoichiometry of the problem. We now have to go back to the reaction equation and write;
[tex]Ti(s) + 2F_{2} (g) --- > TiF_{4} (s)[/tex]
Number of Ti = 2.5g/48 g/mol = 0.052 moles
Number of moles of F2 = 1.7 g/38 g/mol 0.045 moles
If 1 mole of Ti reacts with 2 moles of F2
0.052 moles reacts with 0.052 moles * 2 moles/1 mole
= 0.10 moles
We can see that F2 is the limiting reactant
If 2 moles of F2 1 mole of [tex]TiF_{4}[/tex]
0.045 moles of F2 produces 0.045 moles * 1 mole/2 moles
= 0.0225 moles
Mass of titanium tetrafluoride = 0.0225 moles * 124 g/mol
= 2.79 g
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PLS HELP ME WILL GOVE BRAINLIEST THIS IS URGENT
What we recall about an event is based on actual details of the particular event, plus______
A. Memory reconstruction
B. General knowledge
C. Expectations
D. All of the above
Answer:
A. Memory reconstruction