Chernobyl expelled lots of cs-137 radioisotopes in the environment in 1986. the half-life of cs-137 is 30 years. in 2046, 60 years later, the radioactivity will be zero times the original activity in 1986.
What is half life of a substance?
A drug's half-life is an estimation of how long it will take for its concentration or amount in the body to exactly halve (or 50%) in size. T12 represents half-life.
This well-known phrase was first used in 1907 by renowned physicist Ernest Rutherford, who used the half-life formula to estimate the age of rocks by observing how long radium took to decay into lead.
Here, its said that the half life of Cs-137 is 30 years, that is after 30 years, half of the Cs-137 would have disintegrated, and after 60 years the entire molecule would have disintegrated, hence, after 60 years that is in 2046 the radioactivity would be zero.
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Which bonding type has circular symmetry with respect to the bond axis?
a) sigma bond
b) pi bond
c) delta bond
d) covalent bond
e) ionic bond
Sigma Bond has circular symmetry with respect to the bond axis
Sigma bonds are formed by head-on overlapping between atomic orbitals. These are the strongest type of covalent chemical bond. Pi bond are formed by the lateral overlap of two atomic orbitals. Delta bond is formed by the overlap of four lobes of one involved atomic orbital with four lobes of the other involved atomic orbital.
Covalent Bond is formed by equal sharing of electrons between two atoms. Ionic Bond is formed by the transfer of one or more electrons between atoms.
Sigma bonds are symmetric with respect to the inter-nuclear axis. They also have circular symmetry with respect to the bond axis.
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using this indicator, we will attempt to determine the concentration of various acids depending on the amount of protons available for donation. using a single acceptor base (naoh), we will titrate the acid to the point where it turns pink, representing an equal mixture of acid and base.
Using phenolphthalein indicator, we will attempt to determine the concentration of various acids depending on the amount of protons available for donation. using a single acceptor base (naoh), we will titrate the acid to the point where it turns pink, representing an equal mixture of acid and base
An Phenolphthalein indicator is a ‘dye’ that shows a change in colour when in contact with acids and bases. This tells us whether the substance we are testing is an acid or base with respect to the change of colour. Phenolphthalein indicator when comes in contact with acid and base they give intense pink colour.
Phenolphthalein Colour in acid (pH < 7) give Colourless and Colour at pH = 7 also give Colourless, Colour in base(pH > 7) gives Pink colour that's why using Phenolphthalein indicator we will attempt to determine the concentration of various acids depending on the amount of protons available for donation. using a single acceptor base (naoh), we will titrate the acid to the point where it turns pink, representing an equal mixture of acid and base.
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The lowest portion of the gi tract, where water and electrolytes are absorbed and waste is eliminated, is the __________.
The lowest portion of the GI tract, where water and electrolytes are absorbed and waste removed , is the Large Intestine
What are gastrointestinal diseases?
Gastrointestinal diseases affect the gastrointestinal (GI) tract from the mouth to the anus. They are of two types basically : functional and structural. Some examples include nausea/vomiting, gastrointestinal disorder , lactase deficiency and diarrhea.
What is the GI tract responsible for?
The gastrointestinal system is consist of the gastrointestinal (GI) tract, or the alimentary tract , salivary glands, the liver, and therefore the exocrine pancreas. The main functions of the alimentary canal are to digest and absorb ingested nutrients, and to excrete waste materials of digestion.
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The molecular weight of this compound was determined by mass spectrometry to be 264 g/mol. what is the molecular formula of this compound?
The Empirical Formula for the given compound is C₃H₄O₃ .
What is an Empirical Formula?The simplest whole number ratio of atoms in a chemical molecule is its empirical formula in chemistry.As a result, the empirical formula for sulfur monoxide and disulfur dioxide, two compounds made of sulfur and oxygen, is the same.Their molecular formulae, which represent how many atoms are present in each molecule of a chemical compound, are different.The number of atoms or their arrangement is not mentioned in an empirical formula.The number of each sort of atom in a molecule is displayed in the molecular formula, though.The molecule's organization is represented by the structural formula. Additionally, different types of compounds may have empirical formulas that are equivalent.To learn more about Empirical Formula with the given link
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compare the three characteristics of the states of matter ( solid , liquid and gas)
you answer and i will mark u as brainliest
Explanation:
btw this is secondary school science level :
solid:
•solids have a definite shape and volume.
• they cannot be compressed
•high density
•particles vibrate in a fixed position
•high melting point
Liquid:
•no fixed shape
•partcles are free to move over eachother but are still attracted to one another
•almost incompressible
•have fixed volume but no fixed shape
•denser tagt solids
•there is space between particles
Gas:
•easy to compress
•expand to fill their containers
•particles are free to move around
•Do not have a fixed volume or shape
•gasses can diffuse- their particles move from an are of high concentration to low concentration
•low density
these are just some things of the top of my head. hope it helps
a particular brand of gasoline has a density of 0.737 g/ml at 25 ∘c . how many grams of this gasoline would fill a 13.5 gal tank ( 1us gal
Mass of gasoline = 37662.93 grams.
Density = mass/volume
mass = Density × volume
mass = 0.737 × 13.5 ×3785.41
mass = 37662.93 g
What is gasoline ?The word "gasoline" is an American term for motor vehicle fuel. The trademark "Cazeline" or "Gazeline," which bears the last name of British publisher, coffee trader, and social activist John Cassell, is claimed to have had some impact on the phrase.
Gasoline, usually spelled gasolene, is a blend of flammable, volatile liquid hydrocarbons made from petroleum that is used as internal combustion engine fuel.
Numerous distinct compounds containing hydrogen and carbon make up gasoline (hydrocarbons). About 150 distinct hydrocarbons, including butane, pentane, isopentane, and the BTEX chemicals, are often included in a normal gasoline combination (benzene, ethylbenzene, toluene, and xylenes).
Crude oil, which comprises hydrocarbons, organic compounds formed completely of hydrogen and carbon atoms, is the raw material used to make gasoline.
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Which is an example of potential energy?
A
Water behind a dam
B
A dart stuck in a dartboard
C
Plants using photosynthesis
D
A cow chewing grass
The example of Potential energy is the water behind a dam.
Due to its higher elevation than the water on the other side of a hydroelectric dam , the water behind one stores gravitational potential energy. This potential energy is transformed into kinetic energy when the water falls, turning turbines to produce electricity.
The water held behind the dam has Potential Energy because of its position water in the reservoir is on height and when something is on a certain height the Potential Energy P.E. increases.
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which of the following statements are true about the properties of both molecular and ionic compounds? select all that apply.
They are neutrally charged
They typically do not conduct electricity in solid state
What are ionic compounds?A chemical compound known as an ionic compound in chemistry is one that contains ions bound together by the electrostatic forces known as ionic bonding. Despite having both positively and negatively charged ions, or cations and anions, the molecule is generally neutral.
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Which is the most accurate statement of the phenomenon underlying 'hydrophobicity', the clustering of oily molecules in the presence of water?
The most accurate statement is: water molecules lose opportunities to form bonds with each other when 'interrupted' by oily/hydrophobic ones.
Hydrophobic molecules or hydrophobes have very low solubility in water.
They are nonpolar molecules and do not interact with water molecules.
Oily molecules clump up together in a water because like that, they have minimal interaction with water.
Hydrogen bonds between water molecules (H₂O) will be broken so that the hydrophobes can interact.
When bonds are broken, heat in the system is greater (an endothermic reaction).
Hydrophobic interactions between hydrophobic molecules are spontaneous.
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Using the information below, find how many minutes are in 0.56 yrs.
1 day = 24 hrs
1 yr = 365 days
1 hr = 60 min
There are 294,336 minutes are in 0.56 yrs.
Minutes are a reputable recording of the court cases of a Board meeting Annual fashionable meeting or another meeting and the enterprise transacted on the meeting.
1 yr = 365 days
0.56 = 365 × 0.56
= 204.4 days.
1 day = 24 hrs
204.4 days = 204.4 × 24
= 4905.6 hours
1 hr = 60 min
4905.6 hours = 4905.6 × 60
= 294,336 minutes.
All agencies registered in India are required to maintain mins of all Board and Committee conferences in a minutes e-book. minutes may be created during the meeting with the aid of a typist or courtroom reporter, who might also use shorthand notation and then prepare the minutes and problem them to the contributors afterward.
Minutes are a tangible report of the meeting for its contributors and a source of facts for members who had been not able to wait. In a few cases, assembly mins can act as a reference point, as the instance when a meeting's outcomes affect different collaborative activities or initiatives inside the corporation
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Complete the flowchart about the scientific method.
1.observation
2.hypothesis
3.Experiment
4 solution
5 theory
The independent variable
The dependent variable
An object with a mass of 15.3kg accelerates 3.5.0 m/s2
The force that acts on the body is 53.55 N
What is the force?According to the Newton law, the force is the product of the mass and the acceleration of a body. This is in accordance the Newton second law of motion. We now have to obtain the force that acts on the body.
Mass of the object = 15.3kg
Acceleration of the object = 3.5.0 m/s2
Force = 15.3kg * 3.50 m/s2
Force = 53.55 N
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Read the following information. Which statement describes the homes of the Southwest and Pacific Northwest Native American culture regions best? (3 points)
a Venn diagram comparing the Southwest and Pacific Northwest cultural regions. The Southwest says that they lived in a hot, dry area; they lived in multi-floor buildings made of clay, or in cone-shaped buildings; they wore clothing made of cotton or hides; they grew crops; the were known for weaving blankets, making dolls, and making pottery. The Both sections says they both hunted for meat; they both traded with other tribes; and many people lived together in one home in both cultural regions. The Pacific Northwest says they lived near the coast with lots of forests and rivers; they lived in long, rectangular wooden homes; they wore clothing made of fur or bark; they ate a lot of fish; they traveled in canoes; and they are known for carving totem poles and weaving baskets.
Group of answer choices
Homes in the Southwest and Pacific Northwest had many floors to fit many people.
Homes in the Pacific Northwest and Southwest were made from clay.
Homes in the Pacific Northwest and Southwest were made from wood.
Homes in the Southwest and Pacific Northwest were made from different materials.
Answer:
Homes in the Pacific Northwest and Southwest were made from wood
Explanation:
Carving wood was an essential cultural characteristic in the Southwest and Pacific NorthWest
At what temperature will water change from a liquid to a solid (freeze)?
Answer:
Water changes from liquid to a solid at 32 degrees Fahrenheit
Answer:
32°F
Explanation:
consider the aldol condensation between dibenzyl ketone and benzil in strong base. a reaction was performed in which 0.28 g of dibenzyl ketone was reacted with 0.28 g of benzil to make 0.34 g of 2,3,4,5‑tetraphenylpentadienone. calculate the theoretical yield and percent yield for this reaction.
In organic chemistry, an aldol condensation is a condensation reaction in which an enol or enolate ion combines with a carbonyl chemical to produce a -hydroxyaldehyde or -hydroxyketone, which is then dehydrated to produce a conjugated enone.
Aldol condensations are significant in the synthesis of organic compounds because they offer a reliable method for forming carbon-carbon bonds. Aldol condensation, for instance, occurs during the Robinson annulation reaction sequence, and the Wieland-Miescher ketone product is a crucial building block in numerous chemical syntheses. Aldol condensations are frequently studied as a useful bond-forming reaction that exemplifies significant reaction mechanisms in university-level organic chemistry coursework. in the standard form.
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Calculate the frequency of a wave with a wavelength is 6.0 x 10-7 m.
The frequency of a wave with a wavelength of 6.0 x 10-⁷m is 5.0 × 10¹⁴Hz.
How to calculate frequency?The frequency of a wave can be calculated by dividing the wavelength by its wavelength as follows:
f = v/λ
Where;
f = frequencyv = speed of light (3 × 10⁸m/s)λ = wavelengthAccording to this question, a wave has a wavelength of 6.0 x 10-⁷m. The frequency can be calculated as follows:
f = 3 × 10⁸ ÷ 6.0 × 10-⁷
f = 5.0 × 10¹⁴Hz
Therefore, the frequency of a wave with a wavelength of 6.0 x 10-⁷m is 5.0 × 10¹⁴Hz.
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Find the radius of a cylindrical can (with a lid) to contain 2197 cm3 of water, using the minimum amount of metal. (use symbolic notation and fractions where needed.)
The radius of the cylindrical can is [tex]\sqrt{699.682/h}[/tex]
A cylinder's radius is equal to the distance from the cylinder's center to its edge, which are located at its top and bottom.
A three-dimensional object known as a cylinder is a hollow rod with rounded ends. This circular base's diameter can change, and the radius is equal to half of that value.
A cylinder's radius (r) is equal to [tex]\sqrt{V/\pi h}[/tex], where V denotes the cylinder's volume, h its height, and π (Pi) is a mathematical constant having a value of around 3.14.
Given:
Volume = 2197[tex]cm^3[/tex]
Formula:
Volume, V = π x radius, [tex]r^2[/tex] x height, h
Calculations:
[tex]r^2[/tex] = 2197 / 3.14 x h
[tex]r^2[/tex] = 699.682 / h
Radius, r = [tex]\sqrt{699.682/h}[/tex]
Result:
[tex]\sqrt{699.682/h}[/tex] is found to be the radius of the cylindrical can.
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What molecular features are required for soap to properly dissolve grease and oil?
The soap molecule has two distinct ends, one that is hydrophilic (polar head) that ties with water, and the other that is hydrophobic (non-polar hydrocarbon tail) that secures with grease and oil.
Is the hydrophobic tail polar or non-polar?Per lipid, a molecule includes two parts; a head and a tail. The head is polar and hydrophilic ( Water loving) and the rears are non-polar and hydrophobic( Water hating).
Are hydrocarbon rears hydrophobic?The most productive membrane lipids are the phospholipids. These have an opposing head group and two hydrophobic hydrocarbon tails. The tails are fatty acids, and they can vary in size (they normally contain between 14 and 24 carbon atoms).
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annie learns that the compound sulfuric acid is called the universal chemical. the acid is used in everything from gasoline to paper. annie uses beads in three different colors to model sulfuric acid. based on the model, what is the chemical formula of sulfuric acid?
The compound Annie learns about that is sulfuric acid which is the universal solvent has a chemical formula of H2SO4.
What is the chemical formula of a compound?
The chemical formula of a substance serves as a representation of that substance's chemical make-up. The elements that make up a compound's molecules and the ratio in which their atoms combine to produce those molecules are described in a chemical formula.
The compositions of chemical compounds can be stated in a variety of ways, even though the phrase "chemical formula" is typically used to refer to the molecular formula of a compound, which represents the total number of atoms of each constituent element in one molecule of the compound.
Thus, the compound Annie learns about that is sulfuric acid which is the universal solvent has a chemical formula of H2SO4.
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The table shows the substances used during a science experiment. Which substances are elements?HELP ME PLS!
Answer:What are 10 elements examples?
Examples
H - Hydrogen.
He - Helium.
Li - Lithium.
Be - Beryllium.
B - Boron.
C - Carbon.
N - Nitrogen.
O - Oxygen.
Explanation:
rank the carbonyl‑containing compounds in order of reactivity towards nucleophilic attack. you are currently in a ranking module. turn off browse mode or quick nav, tab to move, space or enter to pick up, tab to move items between bins, arrow keys to change the order of items, space or enter to drop. most reactive least reactive answer bank
From more reactive to least reactive carbonyl‑containing compounds :
3-methylpentanoyl chloride >benzoic anhydride >
butyl acetate> propionamide
The carbonyl carbon should be more electron deficient to increase its reactivity for nucleophilic addition. The presence of R or Ar groups reduces this electron shortage. Less reactivity occurs when more of these groups are present.
The capacity of the electronegative leaving group to activate the carbonyl is connected to the relative reactivity of carboxylic acid derivatives toward nucleophile replacements. The carbonyl loses electron density as a result of the additional electronegative leaving groups, which also increases the carbonyl's electrophilicity.
The reactivity order of carbonyl compounds from more reactive to least reactive :
acyl halide, acid anhydride, aldehyde, ketone, ester, carboxylic acid, amide, carboxylate ion
Benzoyl chloride, acetaldehyde, butyl acetate, and acetic anhydride are more reactive than acid chlorides and anhydrides. Ketones and aldehydes have lower reactivity.
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An extra-strength aspirin contains 0.500 g of aspirin. how many grains is this? (1grain=64.8mg)
By unit conversion, the aspirin contains 7.72 grains.
We need to know about unit conversion to solve this problem. The unit conversion can be used to convert a unit to another unit. It can be defined as
a = xb
where a is unit a, b is unit b and x is the constant of conversion.
From the question above, we know that
m = 0.5 gram
unit conversion
(1 grain = 64.8 mg)
Convert the unit conversion to 1 mg
1 grain = 64.8 mg
1/64.8 grain = 64.8/64.8 mg
1 mg = 1/64.8 grain
Convert the aspirin mass to grain
m = 0.500 g
m = 0.5 x 10³ mg
m = 0.5 x 10³ x 1/64.8 grain
m = 7.72 grain
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Convert 150 mg to grams
Answer: 0.15 grams
Explanation:
Answer: 0.15 grams
Explanation:
to convert milligrams to grams the mass value is divided by 1000, because there are 1000 mg in one g.
Hydrazine, N2H4 , has been used as a rocket fuel because its reaction with oxygen is extremely exothermic:
N2H4(l) + O2(g) -> N2(g) + 2H2O(g) H=-534.0kJ
The enthalpy change for the vaporization of water is given by:
H2O(l) -> H2O(g) H= 40.7kJ
Calculate the enthalpy change that would result if the water were produced in liquid rather than the gaseous form.
N2H4(l) + O2(g) -> N2(g) + 2H2O(l) H=?
Answer:
127
Explanation:
534-107
= 127
It's soo simple you just have to subtract valuew
write the symbol for every chemical element that has atomic number greater than 70 and atomic mass less than 179.5 u
The elements and there symbols are as follows: Oxygen ⇒ O fluorine ⇒ F Neon ⇒ Ne Sodium ⇒ Na.
What is Oxygen ?When a hydrogen atom loses or receives an electron, a hydrogen ion is produced. A positively charged hydrogen ion (or proton) can combine with other particles easily, therefore it is only observed alone when it is in a gaseous condition or a place that is almost particle-free.
The bare hydrogen ion cannot live freely in solution due to its extremely high charge density, which is approximately 21010 times that of a sodium ion. Instead, it rapidly hydrates, or binds, with other molecules. The IUPAC recommends using the phrase "hydrogen ion" to refer to all hydrogen ions and its isotopes. Positively charged ions and negatively charged ions can be divided into two classes based on the ion's charge.
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Why does ether or petrol have a cooling effect when it touches the hand. Just curious
During evaporation, particles of the liquid absorb energy from the surface of the palm to compensate for the loss of energy, making the surroundings cool. The acetone, petrol or perfume take this latent heat of vaporisation from our palm. The palm loses heat and feels cold.
Answer:
When we put some acetone or petrol or perfume on our palm, it evaporates. During evaporation, particles of the liquid absorb energy from the surface of the palm to compensate for the loss of energy, making the surroundings cool. This results in the palm becoming colder.
Explanation:
if 34.4 grams of pentane (c5h12) are burned in excess oxygen, how many grams of h2o will be produced?
If 34.4 grams of pentane ( C₅H₁₂) is burned in excess oxygen, 51.6 grams of H₂O will be produced.
The following reaction occurs when pentane is burned in the presence of excess oxygen,
C₅H₁₂ + 8O₂ = 5CO₂ + 6H₂O
We can observe from the above reaction that,
1 mole of C₅H₁₂ produces 6 moles of H₂O.
Hence,
72 g of C₅H₁₂ produces 108 g of H₂O
1 g of C₅H₁₂ produces 108/72 g of H₂O
34.4 g of C₅H₁₂ produces 108/72 x 34.4 g = 51.6 g of H₂O.
Therefore, if 34.4 grams of pentane ( C₅H₁₂) is burned in excess oxygen, 51.6 grams of H₂O will be produced.
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One of the two amino acids that has a side chain including the modified carboxyl group, carboxamide, is _______________.
One of the two amino acids that has a side chain including the modified carboxyl group, carboxamide, is Asparagine.
Non-essential amino acid aspartic acid (Asp/D) has a carboxyl group in its Rgroup. Oxaloacetate is transaminase to easily create it. At physiological pH, the side chain of aspartic acid has a pKa of 3.9 and is negatively charged.
The side chain of the amino acid cysteine is chemically reactive and capable of forming bonds with other cysteines.
At this location, known as the side chain, each amino acid is joined to a different chemical group. Each amino acid differs from the others due to its side chain, which also gives it a distinctive set of chemical properties. The side chain is frequently referred to as a R group and is represented by the letter R.
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explain 2 ways how there can be forces acting on an object yet the object remains at rest
calculate the cross sectional area occupied by the nucleus as a fraction of that occupied by the atom. assume that the gold nuclei in each layer are offset from each other
For cross sectional area the area occupied by nucleus is 29.01 * 3.16227766e-7.
Cross sectional area is simply πr^2 to be scattered. Let us define this as two at a large angle.
Now define this as the substance noticeable to the nucleus. So if it's two atoms wide, then we required to take hold of the ratio of the cross sectional areas and then multiply it by two. As because of two layers we are hitting the nucleus twice. So now the diameter is divided by two.
Now ,
Particles to be scattered πr^2 / πr^2 = fraction
Radius and mass of nucleus = 3.04 * 10^-15 m, 3.04 * 10^ -23 g
r (nucleus) = 3.04*10^-15 m * 100 cm /1m
= 3.04 * 10^-13 cm
Area = πr^2
= 3.14* 3.04* 3.04* 3.16227766e-7
= 29.01 * 3.16227766e-7
In Rutherford's experiment for a two atom wide layer being scattered.
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