175.93m hope this helps
the half life of radioactive iodine 137 is 8 days. how many iodine nucei are necessary to produce an activity of 1.0 micro Ci?
The half life of radioactive iodine 137 is 8 days 0.0866 iodine nuclei are necessary to produce an activity of 1.0 micro Ci
Here given data is half life of radioactive iodine 137 = 8days
Activity of iodine is = 1.0micro Ci
Radioactive decay is the process by which an unstable atomic nucleus loses energy by radiation and the material containing unstable nuclei is considered radioactive
The interconnection between the decay constant and half-life of any sample can be given by the expression are
T1/2 = (0.693/R); T1/2 = 8
8 = 0.693/R; R=0.0866 R=0.693×1.0/t1/2 = 0.0866
0.0866 iodine nuclei are necessary to produce an activity of 1.0 micro Ci
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use evidence to explain how advancements in technology influenced cell theory
The evidence to explain how advancements in technology influenced cell theory is the invention of microscopes. It has lead the way into the discovery of cells.
The magnification and resolution technology in microscopes have helped the scientists to observe the characteristics of cells and to understand the organization of the life.Cell theory is a scientific theory which was first formulated in the mid-nineteenth century. It states that the living organisms are made up of cells. All cells come from the pre-existing cells. Cells are the basic structural and organizational unit of all the organisms.Technology such as lenses, magnifying glasses, and microscopes had an impact on the development of the cell theory. Below are some examples of how such technologies contributed to the cell theory.The first time the word cell was used to refer to these tiny units of life was in 1665 by a British scientist named Robert Hooke.The invention of the microscope led to the discovery of the cell by Robert Hooke. He observed a box-shaped structures, which he called “cells” as it reminded him of the cells, or rooms, when he was looking at the cork. This discovery led to the formation of the cell theory.After Robert Hooke discovered cells in cork, Anton van Leeuwenhoek in Holland made other important discoveries using a microscope. Leeuwenhoek made his own microscope lenses. His microscope was more powerful than other microscopes of that time. Leeuwenhoek’s microscope was almost as strong as modern light microscopes. Leeuwenhoek used his microscope and became the first person to observe human cells and bacteria.These inventions led to advancements in cell theory.To learn more about cell theory,
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chemistry problem
help!!!!!
Answer:
1+1=2
Explanation:
Which type of energy is the total energy of kinetic energy and potential energy
in a system of objects?
A. sound energy
B. radiant energy
C. mechanical energy
Specify the formal charges (both sign and magnitude) on the atoms labeled a-c.
The formal charges that the atoms bear in the compounds are;
1)
a - zero
b - plus half
c- zero
2)
a - zero
b - zero
c - plus one
What is the formal charge?The formal charge has to do with the charge that an atom appears to have in a compound. We could often decode the formal charge that compound might posses just by an intent look at the compound.
We know that the outermost shell of all the atoms in a compound ought to have eight electrons. This implies that all the atoms of elements in a compound must obey the octet rule. The atoms that do not obey the octet rule must bear a formal charge.
The formal charges that the atoms bear in the compounds are;
1)
a - zero
b - plus half
c- zero
2)
a - zero
b - zero
c - plus one
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What volume of a 0.35 M NaCl solution would contain 23.0 grams of NaCl?
With 25 grams of sodium chloride, 1.2 liters of a 0.35 M solution of sodium chloride may be created.
The quantity of solute dissolved in one liter of solution is known as molarity (M).
Molarity (M) is defined as the number of moles of a solute divided by the volume of the solution in litres.
M = n / v where
M stands for molarity, n for moles, and V for volume of solution.
NaCl's molar mass is 23 g/mol plus 35.5 g/mol.
= 58.5 g/mol
Now,
Given mass/molar mass equals the number of moles (n).
= 0.427
We must now determine the solution's volume.
M = 0.35 = 0.427 / v
V is 1.2 liters
Thus, 25 grams of sodium chloride might be used to create 1.2 liters of sodium chloride solution at 0.35M.
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Why does the temperature of the boiling water stop changing as you continue to add heat?
inging as you
The temperature of the boiling water stop changing as you continue to add heat because all the heat energy is used up in changing water from liquid state to vapor state.
When we heat the water and once water starts boiling , the heat supplied will be used in state conversion , from liquid to gaseous vapour. in other words, energy added to liquid used into breaking bonds between liquid molecules without changing the temperature.
All the energy provided in the form of heat increases the kinetic energy of particles and temperature does not increase. The boiling point of water depends on atmospheric pressure. At 1 atm the boiling point of water is 100°C.
Hence, The temperature of the boiling water stop changing as you continue to add heat because all the heat energy is used up in changing water from liquid state to vapor state.
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(01.01 LC)What is the body of scientific knowledge based on?
Guesses
Mysteries
Observations
Opinions
The body of scientific knowledge is based on different Observations (Option C).
What does observations mean in the scientific method?Observations in the scientific method are fundamental because it is the first step to raising scientific questions that may be explained through plausible hypotheses. Subsequently, hypotheses must be tested by experimental procedures.
In conclusion, the body of scientific knowledge is based on different Observations (Option C).
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Consider the reaction of cesium metal with gaseous fluorine to produce cesium fluoride. How many cesium atoms are on the product side of the equation?
Based on the equation of the reaction, there are two cesium atoms on the product side of the equation.
What is the equation of the reaction between cesium and fluorine?Cesium is a metallic element that is found in the group 1A of the period table.
Cesium therefore has one valence electro which it can donate to an electronegative element to form a compound wit the element.
Fluorine belongs to the group 7A of the period table known as the halogens.
Fluorine accepts one electro from an electropositive element to form a compound with the element.
The equation of the reaction between cesium and fluorine is given below:
2 Cs + F₂ → 2 CsFThere are two cesium atoms on the product and reactant side of the equation.
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What laboratory equipment do you need to prepare 250 mL of a 0.010 M solution of NaCl from a stock solution?
The equipment we used to prepare 250 ml of a 0.010 M solution of NaCl from a stock solution is Volumetric flask (piece of lab).
It is calibrated to comprise a precise volume (v) at a given temperature.
It is used for accurate results in dilutions and to prepare a solutions that is needed according to the experiment.
Volumetric flask short form is vol flask.
A stock solution is defined as the standard solution made using nearly accurate experiment.
Example of stock solution - Two M sol of tris-HCL, 5M sol of NaCl.
Stock Solution formula = C1*V1 = C2*V2
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Which of the following choices is the one that does NOT describe a chemical
property?
Concentrated hydrochloric acid will burn a hole in cotton jeans because the acid
breaks down the cellulose fibers in cotton.
Copper metal combines with substances in the air to form a green "patina" that
protects the copper from further reaction.
Copper compounds often form beautiful blue crystals when a solution of a given
copper compound is evaporated slowly.
Oven cleaners contain sodium hydroxide, which converts the grease/oil spatters
inside the oven to water-soluble materials, which can be washed away.
Hydrogen peroxide fizzes when it is applied to a cut or scrape.
The following choice is not a chemical property is Copper compounds often form beautiful blue crystals when a solution of a given copper compound is evaporated slowly.
Chemical Property is defined as the any substance's or particles properties that can be seen changing before and after is known as chemical property.
Ignitible, pH value, chemical stability are some of the properties of chemical property.
The other options are chemical property first one is burning a piece of cloth and leave another acid, another one is forming a gas, the another one is also changing the property into soluble form , and the last one is wound is fizzing so it is also a chemical property.
Hence, the option (c) isn't a chemical property.
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If 1.00 mol of argon is placed in a 0.500- L container at 24.0 ∘C , what is the difference between the ideal pressure (as predicted by the ideal gas law) and the real pressure (as predicted by the van der Waals equation)? For argon, a=1.345(L2⋅atm)/mol2 and b=0.03219L/mol .
Express your answer to two significant figures and include the appropriate units.
The difference between the ideal pressure and the pressure calculated by the Van Der Waal equation is 2.08 atm.
What is the pressure?In this problem, we are mandated to obtain the pressure both by the use of the ideal gas equation and then the use of the Van der Walls equation.
Using the idea gas equation;
PV = nRT
P = nRT/V
P = pressure
V = volume
n = number of moles
T = temperature
R = gas constant
P = 1 * 0.082 * (24 + 273)/0.5
P = 48.7 atm
Using the Van Der Wall equation:
P = RT/(V - b) - a /V^2
P = 0.082 * 297/(0.5 - 0.03219) - 1.345/(0.5)^2
P = 24.354/0.46781 - 1.345/ /0.25
P = 52 - 5.38
P = 46.62 atm
The difference between the ideal pressure and the pressure calculated by the Van Der Waal equation is; 48.7 atm - 46.62 atm = 2.08 atm
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Bimetallic meters can be used to measure temperatures from ____°F to __°F.
O-300; 800
O-300; 100
O-112; 760
O-100; 500
-300;800 is the correct answer
(01.05 LC)
Which of the following is a sign a chemical reaction has occurred? (4 points)
Select one:
O
a.A solid dissolves in a liquid.
b.A solid forms when two liquids are mixed.
c.A solid melts to a liquid when it is heated.
d.A solid metal changes shape.
(01.05 LC)
When heat energy is added, two changes are
Answer:
it is A trust me I know thank you
What are some examples of synthetic products made from metal ores?
Some examples of synthetic products made from metal ores include, aluminum, cobalt, copper, gold, plastics.
What are metal ores?Metal ores are the rocks from which metal is mostly extracted from, usually in a commercial quantity.
Also, metal ores are naturally occurring rocks that contain metals or metal compounds in sufficient amounts to make it worthwhile extracting them.
The method used to extract a given metal from its ore depends upon the reactivity of the metal and so how stable the ore is.
Examples of metal ores;
Cinnabar is ore of mercury, Sphalerite is ore of zinc,Cassiterite is ore of tin Some examples of synthetic products made from metal oresaluminum, cobalt, copper, goldplasticsThus, some examples of synthetic products made from metal ores include, aluminum, cobalt, copper, gold, plastics.
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Previously cooked food must reheated to
Previously cooked food must reheated to temperatures of at least 165°F.
What temperature must previously cooked food must reheated to?When food is cooked, it should be eaten and any leftovers preserved.
Leftovers can be preserved by refrigeration.
However, when this refrigerated food is to be eaten again, it should be reheated before eating.
Previously cooked food must be heated to prevent spoilage and poisoning.
The addition of heat will prevent spoilage by:
Killing most microorganisms that may be present in the fooddenaturing the activity of the enzymes present in these organisms.Previously cooked food must reheated to temperatures of at least 165 °F.
The process of reheating the food may be done in microwave oven or over a stove.
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176.5 cm to meters express your answer to four significant figures and include the appropriate units
Answer:
17,650 m
Explanation:
100 cm = 1m so, 176.5 × 100 = 17,650m
what is the thing aroud the nucisel
Answer:
Electrons
Explanation:
Assuming you are talking about the nucleus of an atom, the particles surrounding the nucleus are electrons.
Atoms consist of three subatomic particles: protons, neutrons, and electrons. Protons and neutrons are located within the nucleus, whereas the electrons exist outside of it.
Fe in Prussian blue, Fe4[Fe(CN)6]3 (a pigment used in paints and printing inks)
Express your answer using five significant figures. Determine the percent,by mass, for Fe
The percent by mass of iron in Prussian blue is 32.6%.
What is Prussian blue?The salt called Prussian blue is a salt that is of the family of the ferrocyanide salts. They are commonly used as dyes. This compound as it is know could be used as a blue dye in many quarters. In medicine it could be used to assist the body to expedite the elimination of certain elements or harmful chemicals from the body.
We are here mandated to obtain the percent by mass of the iron atom in the Prussian blue;
Molar mass of Prussian blue = 859
Mass of iron in Prussian blue = 5(56) = 280
Percent by mass of Prussian blue = 280/ 859 * 100 = 32.6%
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Give three examples of how energy is transferred.
Calculate the mass of camphor (C₁0H₁60) that contains a billion (1.0 × 10°) carbon atoms.
Be sure your answer has a unit symbol if necessary, and round it to 2 significant digits.
Mass of camphor is 252.47 g and mass is a measure of the amount of matter in a substance or an object
Camphor, an organic compound of penetrating, somewhat musty aroma, used for many centuries as a component of incense and as a medicinal. Modern uses of camphor have been as a plasticizer for cellulose nitrate and as an insect repellent, particularly for moths and the molecular formula is C₁₀H₁₆O
Here given data is camphor (C₁₀H₁₆0) that contains a billion (1.0 × 10°) carbon atoms
So, 1.0×10⁰ carbon atom×1 molecule of camphor/1 carbon atom
1 molecule of camphor×1 mole of camphor/Avogadro's number
1 molecule of camphor×1 mole of camphor/6.06×10²³ molecule
= 1.661 mole of camphor
1.661 mole of camphor ×152 g camphor = 252.47 g camphor
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Which action best completes the diagram showing how the federal budget is
created?
?
The president submits a budget plan to Congress.
Congress debates and finalizes the budget.
Congress returns the budget to the president.
The president signs the spending bill into law.
A. The president reviews the budget with the Supreme Court.
OB. Congress votes on requirements for a budget plan.
C. State governments submit their budget proposals.
OD. Executive agencies submit budget requests.
The process that completes the way that the the federal budget is created is that executive agencies submit budget requests.
What is the budget?The budget refers to the way in which the expenditure of the government is to be run in the coming year. It is customary that the executive must present their budget to the legislative arm of the government for consideration. It must be noted that the budget that has been drafted by the executive arm of government could only be passed into law by the legislative arm.
It is important to note that the legislative arm of government is composed of both the senate and the congress and the both chambers of the legislature must have to individually pass the appropriation bill before it could be passed into law by the president.
Hence, the process that completes the way that the the federal budget is created is that executive agencies submit budget requests.
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PLEASE HELP ME THERES 100 POINTS ON THE LINE
Answer:
1.93 2.86
Explanation:
exactly the reason for the above text
Question 7 of 10
What property is used to calculate the pH of a solution?
Answer:
The hydrogen ion concentration in mol/L
Explanation:
Answer:
The pH of a solution is a measure of hydrogen ion concentration in mol/L
Explanation:
the concentration of hydrogen ions in a solution expressed usually in moles per liter or in pH units and used as a measure of the acidity of the solution
According to the article, elements are named by the number of protons in the nuclei.
Which paragraph BEST supports the idea outlined above?
A
The periodic table is getting a little bit longer, thanks to the addition of four super-heavy elements.
B
The discoveries of elements 113, 115, 117 and 118 were confirmed recently by the International Union of Pure and Applied Chemistry. The group vets the man-made elements seeking a permanent spot on the periodic table, a chart listing all the elements that hangs in science classrooms around the world.
C
Atoms are the building blocks that make up elements. At the center of each atom is a nucleus composed of small particles called protons and neutrons. Nuclei is the plural of nucleus.
D
The new elements are known as super-heavy elements. Element 118, for example, is the heaviest element to date, with 118 protons alongside 176 neutrons.
The correct answer is: Atoms are the building blocks that make up elements. At the center of each atom is a nucleus composed of small particles called protons and neutrons. Nuclei is the plural of nucleus; option C.
What is atomic number of an element?The atomic number of an element is the number of protons present in the nucleus of the atom of the element.
The nucleus is the center of the atom and is the heaviest part of the atom.
Another sub-atomic particle fund in the nucleus is the neutron.
Elements are named according to the number of protons in the nuclei.. This is because the number of protons in the nucleus of any given atom whereas the neutron number may vary, Also, electrons are easily removed from atoms of elements.
In conclusion, the number of protos in atom is used to name the atom.
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A polystyrene cup is used to minimise thermal energy loss.
a. Explain why it is important to take steps to minimise thermal energy loss.
b. How else could thermal energy loss be minimised in this experiment?
PLEASE HELP
A polystyrene cup is used to minimise the thermal energy loss because polystyrene cup is acts as a very good insulator.
It is important to use polystyrene cup to minimise thermal energy loss because it prevent the heat energy loss as it has air bubbled trapped inside them. if we hold a hot coffee in a polystyrene cup , the hot coffee does not burn your finger because it is a bad conductor of heat. it is a natural insulator. we can also use this styroform or polystyrene idea to make home warm in cold region , it reduce the transfer of heat ,so that building stays warmer.
We can use plastic foam to reduce heat energy loss . Both polystyrene and plastic foams are the good insulators and bad conductor of heat.
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4.00 x 10-2 mL of bromine (a liquid element) weigh 0.1249 g. What is the density of bromine?
The density of 4.00 mL x 10⁻² mL of bromine (liquid) weighing 0.1249 g is 3.1225 g/mL.
Density of a liquid is defined as the mass of the substance per unit of its volume. Density is equal to the mass divided by the volume of any liquid. It is denoted by a Greek letter ρ. It is given by -
ρ = m
v
where,
ρ = density
m = mass
v = volume
To calculate the density of bromine liquid,
We use,
Density = mass
volume
Density = 0.1249 g
4.00 x 10⁻² mL
Density = 3.12 g/mL
Therefore, the density of bromine liquid is 3.12 g/mL
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One anabolic steroid is fluoxymesterone (C20H29FO3). Calculate the percent composition of carbon by mass of
fluoxymesterone.
Answer:
Percent Composition (C) = 71.40%
Explanation:
To find the percent composition of carbon by mass, you need to (1) calculate the molar mass of C₂₀H₂₉FO₃ (using the atomic masses of each atom in the molecule), then (2) calculate the total amount of carbon in C₂₀H₂₉FO₃ (using the atomic mass of carbon), and then (3) calculate the percent composition of carbon.
(Step 1)
Atomic Mass (C): 12.011 g/mol
Atomic Mass (H): 1.008 g/mol
Atomic Mass (F): 18.998 g/mol
Atomic Mass (O): 15.999 g/mol
Molar Mass (C₂₀H₂₉FO₃):
20(12.011 g/mol) + 29(1.008 g/mol) + 18.998 g/mol + 3(15.999 g/mol)
= 336.447 g/mol
(Step 2)
Atomic Mass (C): 12.011 g/mol
Total Mass (C): 20(12.011 g/mol) = 240.22 g/mol
(Step 3)
mass of carbon
Percent Composition (C) = ----------------------------- x 100%
mass of molecule
240.22 grams
Percent Composition (C) = ----------------------------- x 100%
336.447 grams
Percent Composition (C) = 71.40%
what is annulus class 9 modern book
A series of concentric circles make form the geometric shape known as the annulus. Each circle has the same radius, and there is an equal distance between them. Both the size of a circular region and the circumference of the circle can be determined using the annulus.
An animal or plant's annulus is a ring-shaped structure. The portion of the stem that holds the leaves in place on plants is known as the annulus. The stem's annulus, which similarly shrinks to let the plant move, is another example of this. The portion of the skeleton that encircles the spinal cord in animals is known as the annulus. The annulus helps to maintain the body upright while safeguarding the spinal cord.
A new ring is built on a molecule via the chemical reaction known as annulation in organic chemistry. Helicenes and acenes are two examples of side-on condensed cyclic segments that are used to build annular molecules.
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State the charge on an electron
-1
0
+1
Answer:
an electron charge is -1