Cells from the air would have fallen into the sterilized growth medium in the flask and grown there if Pasteur had broken off the swan neck of the flask one week after boiling the nutrient broth to sterilize the flask.
Who was Pasteur?He was referred to as a microbiologist who was responsible for many advances in science through experiments and an example is the one which was done using broth.
He heated the flask after it was sealed to kill microbes present in it and the result was nothing grew in the sample. However, if he had broken off the swan neck of the flask one week after boiling, cells from the air would have fallen into the sterilized growth medium in the flask and grown there.
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Which of the following describes our modern model of the atom? (1 pt)
*
1 point
solid sphere like a marble but unique to the element it makes
numerous positive charges floating around in a sea of negative charge (plum pudding)
positive nucleus surrounded by a blob of negative charge
positive nucleus surrounded by electrons in circular orbits
positive nucleus surrounded by electron orbitals with complex 3-D shapes and assigned energies.
Modern model of the atom states that an atom is made up of a core nucleus around which protons, neutrons, and electrons are in highly probable orbits.
What is an atom?The fundamental unit of chemistry is the atom. It is the smallest particle that can be separated into matter without releasing electrically charged particles.
Additionally, it is the smallest piece of matter with the characteristics of a chemical element.
Thus, Modern model of the atom states that an atom is made up of a core nucleus around which protons, neutrons, and electrons are in highly probable orbits.
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if the copper(ii) chloride solution splashes on your skin while you are preparing the solution, what actions should you take?
If copper (ii) chloride solution splashes on your skin while preparing the answer, you ought totell your teacher about the accident right away and use water to rinse the part of your skin that came in contact with the chemical.
Copper (ii) chloride solution is an inorganic salt. In its anhydrous form, it appears as a yellowish-brownie powder. Its hydrous form may be type of blue green crystalline solid. It forms a blue green solution. It's used in making dyes, fungicides, printing and as a wood preservative.If it comes in contact with the eyes, it can cause irritation and blindness. If it is come in touch with the skin, it can cause severe irritation. The part of the skin in contact with the chemical should be rinsed immediately, preferably with soap. Soap should be used to rinse the affected area along with water.Copper Chloride (CuCl₂) is light brown solid which forms a blue green dihydrate solution on absorbing moisture.
From the above conclusion we can say that, If copper (ii) chloride solution splashes on your skin while preparing the solution, you should tell your teacher about the accident right away and use water to rinse the part of your skin that came in contact with the chemical.
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Separating sand and salt by filtration and evaporation, what are the observations in the experiment?
While Separating sand and salt by filtration and evaporation, the observation is during the filtration the sand gets accumulated in the filter paper while separating it from the salt solution, while in evaporation the salt gets accumulated.
When we tried to separate the individual components from the mixture of the salt and sand the first step is dissolving the mixture in water as the salt gets dissolved so it is easy for us to filter the sand from the solution, it is followed by the method of evaporation, in which the filtered salt solution is boiled until the water gets evaporated and we are left with the salt, that's how salt and sand are separated from a mixture.
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When mercury oxide is heated, it decomposes into mercury and oxygen. If 28. 4 g of mercury oxide decomposes, producing 2. 0 g of oxygen, what is the percent by mass of mercury in mercury oxide?.
The percent by mass of mercury in mercuric oxide is
93 %.
The molecular formula of mercuric oxide is HgO. Mercury is liquid at room temperature and readily combines with oxygen to form mercuric oxide. Mercury is represented by the symbol Hg. The mass percent is defined as the ratio of the mass of the reactant to the mass of the product into 100. When mercuric oxide undergoes decomposition, it gives mercury and oxygen. And this reaction is endothermic.
The balanced equation for the reaction of mercury oxide is,
[tex]2HgO (s)→ 2Hg (l) + O _{2}(g)[/tex]
Mass of mercury oxide = 28.4 g
Mass of the oxygen = 2 g
The percent by mass of mercury in mercury oxide is,
[tex]Mass ℅= \frac{Mass \: of \: Mercury }{Mass \: of \: Mercury \: oxide} \times 100[/tex]
[tex]= \frac{28.4 - 2}{28.4} \times 100[/tex]
= 93 %
Therefore, the percent by mass of mercury in mercury oxide is 93 %.
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which element could not form in the sun and would have to be formed in a supernova? hydrogen (atomic number 1) hydrogen (atomic number 1) helium (atomic number 2) helium (atomic number 2) oxygen (atomic number 8) oxygen (atomic number 8) uranium (atomic number 92)
Uranium is the element which could not form in the sun and would have to be formed in a supernova
What is Uranium ?With an atomic number of 92, uranium is a metallic chemical element in the periodic table that is silvery-white. The chemical symbol for it is U. There are 92 protons and 92 electrons in an atom of uranium, of which 6 are valence electrons. The atomic weight of uranium is the greatest among all naturally occurring elements.
Nuclear power facilities, as well as the nuclear reactors that power ships and submarines, can be powered by uranium that has been "enriched" to have a higher proportion of U-235. In nuclear weapons, it can also be applied.Kidneys are uranium's primary target organ. Both people and animals have had kidney impairment as a result of breathing or swallowing uranium compounds.Learn more about Uranium here:
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pls explain how u do it aswell ty
[tex]2CO + O_{2} ---- > 2CO_{2}\\2Na + 2H_{2} O---- > 2NaOH + H_{2} \\2P + 3Cl_{2} ------ > 2PCl_3} \\Pb_{3} O_{4} +HNO_{3} ------ > 2Pb(NO3)_{2} + H_{2} O + PbO_{2}[/tex]
What is a reaction equation?A reaction equation is a representation of the reaction that takes place in the reaction vessel. We know that a reaction equation is balanced when the number of atoms of each of the elements is the same on both sides of the reaction equation.
We can achieve the balancing of the reaction equations by the process of an atom count. We try to find out if we have the same number of atoms on both sides of the reaction equation by carrying out a literal counting of the atoms.
Let us now attempt to write the balanced reaction equation in each case;
[tex]2CO + O_{2} ---- > 2CO_{2}\\2Na + 2H_{2} O---- > 2NaOH + H_{2} \\2P + 3Cl_{2} ------ > 2PCl_3} \\Pb_{3} O_{4} +HNO_{3} ------ > 2Pb(NO3)_{2} + H_{2} O + PbO_{2}[/tex]
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how do i identify a compound
Various criteria can be used to categorize chemical substances. One such approach is based on the distinct components present.
All other chemicals are categorized as inorganic, and organic compounds are defined as those possessing a carbon atom backbone. Organometallic compounds are organic molecules bound to metal atoms, as their name suggests.
The sorts of bonds that a compound has served as the basis for another classification system for chemical compounds. Ions are present in ionic compounds, which are held together by the attraction interactions between the ions with opposing charges. One of the most well-known ionic compounds is table salt or sodium chloride.
Reactivity, or more specifically, the kinds of chemical reactions that the compounds are most likely to experience, is the basis of a third classification system.
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Write down the reaction you think will occur after you immerse the egg in the vinegar. Come back in an hour, and record
your observations.
When immerse the egg in the vinegar then we see 'bubbles on the shell'
Here given data is when we immerse the egg in the vinegar then soak this egg shell in vinegar and in that chemical reaction will start because in vinegar acetic acid are seen and that dissolve calcium carbonate shell and the acetic acid reacts with the calcium carbonate in the egg shell and releases carbon dioxide gas that you see as bubbles on the shell after an hour we will back then egg shell are soaked by vinegar
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True or false: One reason people needed calendars in the past was to know when it was time to plant and harvest crops.!
Answer:
True
Explanation:
the time you plant crops matters alot. especially in times before pesticides and greenhouses.
Answer: False
Explanation:
People went by what the seasons were to find out what to grow. Calendars merely helped with remembering important dates like when is Halloween, when is president's day, etc..
What are the numbers on the right side of an element?
Answer:
It's the atomic weight for that particular element, atomic weight is just the number of protons in the element
Explanation:
okay have a good day!
question 7 briefly explain why the two pi-bonds of an alkyne triple bond are required to be oriented perpendicular to one another.
Pi bonds, on the other hand, are ties between p-orbitals on nearby atoms. The two pi bonds in an alkyne are also perpendicular since the p-orbitals are by definition parallel to one another.
What is the name of a triple bond?Alkynes are defined as molecules with a triple bond between two carbon atoms. One bond and two bonds combine to form the triple bond.
What is the formula for alkynes?Alkynes are hydrocarbons that have triple bonds between carbon atoms. When it comes to molecules with one triple bond, their usual formula is CnH2n-2 (and no rings).
How are alkynes created?Alkynes are aliphatic hydrocarbons that are acyclic (branched or unbranched) and have one triple bond between carbon atoms, giving them the typical chemical formula CnH2n-2 [18]. Triple bonds are shorter and more powerful than double bonds, continuing the trend.learn more about alkyne here
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waters density is ___ the cooking oil and mercury
Answer:
ANSWER :: (DENSITY OF OIL IS --0.8/CM²) .
(DENSITY OF MERCURY IS --- 13.69/CM²) .
1. What is given off by a nucleus undergoing each of the following types of decay? (draw each of the
particles as an isotopic (nuclear) symbol)
A. Alpha
B. Beta
C. Gamma
The following is given out by the particles undergoing these types of decay;
A. Alpha - Helium nucleus 4/2He
B. Beta - An electron 0/-1 e
C. Gamma - A gamma ray 0/0 γ
What is a radioactive decay?We know that the term radioactivity is the term that we often use to describe the spontaneous disintegration of the atoms of a substance which often leads to the formation of a new substances an the release of energy. The process by which the radioactive atoms are broken down is what we call the process of radioactive decay.
Now we know that radioactive decay is a very important process and was developed largely due to the research of the scientist that is called Maria Curie.
The following is given out by the particles undergoing these types of decay;
A. Alpha - Helium nucleus 4/2He
B. Beta - An electron 0/-1 e
C. Gamma - A gamma ray 0/0 γ
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in example 4.2, you found that a particular mixture of co and h2 could produce 407 g ch3oh. co(g) 2 h2(g) n ch3oh(l) if only 332 g of ch3oh is actually produced, what is the percent yield of the compound?
The percent yield is given by the division of the actual yield and theoretical yield. The percent yield methanol (CH₃OH) compound is calculated to be 81.57%.
What is the percent yield?The percent yield is the reaction yield that is estimated by the actual and the theoretical yield that is never greater than 100% and has been the ratio of the actual to the theoretical yield multiplied by 100.
The percent yield is given as:
Percent yield = actual yield ÷ theoretical yield × 100%
Given,
Theoretical yield = 407 gram
Actual yield = 332 grams
Substituting values as:
Percent yield = 332 ÷ 407 × 100%
= 81.57 %
Therefore, the percent yield is 81.57%.
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please help me figure out how many significant figures are in there
Answer:
A) 4 and 3
Explanation:
You don't count the scientific notations in his problem sine they are only trailing zeros which they don't count as sig figs so look at the original numbers. Remember that zeros after decimal points or in-between natural numbers count with that said 2.020 has 4 sig figs and 5.00 has 3 sig figs
A solid precipitate is formed from the reaction of lead nitrate and sodium chromate.
Lead chromate (PbCrO4) is the solid precipitate formed from the reaction of lead nitrate and sodium chromate.
A precipitate is a compound that comes out of a liquid solution and it insoluble. The chemical substance which causes the formation of solid to form is called the precipitant. Lead chromate (PbCrO4) is as hard as a brick.
The chemical equation of the reaction is:
Pb (NO3)2 + NA2CrO4 → Pb (CrO4) + 2Na (NO3)
This reaction is known as Double Displacement or Metathesis. Lead chromate emerges as a solid precipitate with a yellow color.
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Dilution of a buffer solution with a small amount of water will ________ the ph of the solution.
The Dilution of a buffer solution with a small amount of water will raise the PH of the solution. Dilution is the process of "reducing the concentration of a solute in a solution by simply adding more solvent to the solution, such as water." Dilution involves increasing the amount of solvent in a solution without increasing the amount of solute.
When a solvent is added, the concentration of the solute in the solution is diluted. By removing the solvent, concentration raises the solute concentration in the solution. Dilution is the process of lowering a given solute's concentration in its solution.
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Based on the amino acid sequences of each histone, estimate the charge of a histone octamer at ph 7. Assume that histidine residues are uncharged at this ph.
Assuming histidine residues as uncharged, the total charge of the Histone octamer at pH 7 is +146.
Histone H2A has a total of 26 positively charged residues (Arg + Lys) and 9 negatively charged residues (Asp + Glu).
The net charge is 26 – 9 = + 17
Histone H2B has a total of 28 positively charged residues (Arg + Lys) and 10 negatively charged residues (Asp + Glu).
The net charge is 28 – 10 = + 18
Histone H3 has a total of 31 positively charged residues (Arg + Lys) and 11 negatively charged residues (Asp + Glu).
The net charge is 31 – 11 = + 20
Histone H4 has a total of 25 positively charged residues (Arg + Lys) and 7 negatively charged residues (Asp + Glu).
The net charge is 25 – 7 = + 18
The histone octamer's overall charge is equal to 2 x (17 + 18 + 20 + 18) = +146.
The complete question is:
Based on the amino acid sequences of each histone, estimate the charge of a histone octamer at pH 7. Assume that histidine residues are uncharged at this pH.
Histone H2A
M S G R G K Q G G K A R A K A K T R S S R A G L Q F P V G R V H R L L R K G N Y S E R V G A G A P V Y L A A V L E Y L T A E I L E L A G N A A R D N K K T R I I P R H L Q L A I R N D E E L N K L L G R V T I A Q G G V L P N I Q A V L L P K K T E S H H K A K G K
Histone H2B
M P E P A K S A P A P K K G S K K A V T K A Q K K D G K K R K R S R K E S Y S V Y V Y K V L K Q V H P D T G I S S K A M G I M N S F V N D I F E R I A G E A S R L A H Y N K R S T I T S R E I Q T A V R L L L P G E L A K H A V S E G T K A V T K Y T S S K
Histone H3
M A R T K Q T A R K S T G G K A P R K Q L A T K A A R K S A P S T G G V K K P H R Y R P G T V A L R E I R R Y Q K S T E L L I R K L P F Q R L V R E I A Q D F K T D L R F Q S A A I G A L Q E A S E A Y L V G L F E D T N L C A I H A K R V T I M P K D I Q L A R R I R G E R A
Histone H4
M S G R G K G G K G L G K G G A K R H R K V L R D N I Q G I T K P A I R R L A R R G G V K R I S G L I Y E E T R G V L K V F L E N V I R D A V T Y T E H A K R K T V T A M D V V Y A L K R Q G R T L Y G F G G
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consider a system of two atoms, each having ony 3 quantum states of energies 0, e and 2s. the system is in contact with a heat reservoir at temperature t. w
A system of two atoms, each having only 3 quantum states of energies 0, e and 2s. The system is in contact with a heat reservoir at temperature T.
The quantum state of a particle is defined by the values of its quantum numbers, so what this implies is that no two electrons within the same atom can have the identical set of quantum numbers.
In natural philosophy, a quantum state may be a mathematical entity that gives a probability distribution for the outcomes of every possible measurement on a system. Knowledge of the quantum state along with the foundations for the system's evolution in time exhausts all which will be predicted about the system's behavior.
For example, the spin of an isolated electron can tackle one amongst only two values; there aren't any other quantum states available for the electron and no intermediate values, since spin is quantized . As a physical parameter is varied, quantum fluctuations can drive a natural action into a special phase of matter.
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If the mass of an object stays the same, but its volume increases, the density of the object will
A: decrease
B: increase
C: stay the same
D: get heavier
Answer:b
Explanation: Edge 22
. which type of bond exemplifies a weak chemical bond? covalent bonds in solution hydrogen bonds in solution ionic bonds in solids nonpolar covalent bonds in solids
Hydrogen bond exemplifies a weak chemical bond.
Hydrogen bond is weak because electrons are not transported to form opposing, attracting charges as they are in ionic bonds or shared as they are in covalent bonds.when hydrogen is covalently bonded to a more electronegative atom, that atom pulls the hydrogen's electron away from it, causing it to become attracted to nearby electronegative atoms with unpaired electrons. As a result, hydrogen has a slight positive charge.The electrostatic contact between the atoms caused by the gain or loss of electrons results in the formation of ionic bond which is the strongest bond. The sharing of electrons or the overlapping of two atomic orbitals results in the formation of covalent bonds.When two atoms share electrons equally, a non-polar covalent bond is created.Therefore, among all these bonds hydrogen bond is the weakest.
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if you were going to be handling harmful chemicals in a lab, what safety equipment would you use to protect your eyes and face?(1 point)
Chemical splash goggles or face shields should be worn when there is a risk of splashing hazardous materials or flying particles.
What are safety equipment would you use to protect eyes and face ?Put on this protective gear before dealing with hazardous chemicals in a lab to protect your face and eyes.
If a substance has the ability to damage a surface upon touch, it is corrosive. People who inhale the fumes from these substances run the risk of burning their eyes, skin, and internal organs.These chemical burns can be avoided by closely following the biosafety protocol that a laboratory requires the use of masks, goggles, gloves, and an apron or lab coat.The regulations for biosafety in a lab necessitate that the subject not possess the exposed skin and eyes.Learn more about Lab safety here:
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deduce the correct order of the following elements in order of decreasing atomic radius: cl, n, na and f.
Correct order of the following elements in order of decreasing atomic radius are as follow N>F>Na>Cl
Atomic radius is the distance from atoms nucleus to the outer edge of the electron cloud. atomic radius decreases across a period and increases down the group across a period effective nuclear charge increases as electron shielding remain constant. In this order nitrogen and Florine are arranged in period from left to right and also sodium and chlorine are arranged in period from left to right. we move from left to right in a period atomic radius decreases.
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A histogram is a chart that shows the spread of data, that allows us to
see outliers and
O a. Errors
O b. Symbols
O c. Wrong answers
Od. Best number
A histogram is a chart that shows the spread of data, which allows us to see outliers and the best number that fits with the data (Option D).
What is a histogram?A histogram is a diagram used to show the relationships between two different variables, which is represented by rectangles that indicate a specified amount of a given parameter in the representation.
In conclusion, a histogram is a chart that shows the spread of data, which allows us to see outliers and the best number that fits with the data (Option D).
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Describe Emotions in the room after “The Vote!” during July 2, 1776 U.S History
Answer:
On July 4, 1776—the day the Declaration of Independence was approved by the Second Continental Congress—the prevailing mood was trepidation and fear.
Explanation:
rank the following compounds in terms by increasing boiling point, starting with the lowest boiling point first.
N-Pentane has a higher boiling point than the other three elements
||| < || < | < |V
n-Pentane and 2,2-Dimethylpropane are isomers of one another and have the same chemical formula. Only London dispersion forces (LDFs), the smallest intermolecular forces, exist between the two molecules. The connectedness of the carbon skeleton accounts for the variation in their boiling points. While 2,2-dimethylpropane is a branching hydrocarbon, n-pentane is a straight hydrocarbon. Because of the n-linear pentane's shape, which results in greater surface areas between molecules, there are more LDFs between the molecules. N-Pentane has a higher boiling point as a result.
Because they have hydrogen bonds, 1-pentanol and (R)-4-hydroxypentanoic acid have higher boiling points than hydrocarbons. While (R)-4-hydroxypentanoic acid has both an alcohol group and an acid group, which can also hydrogen, 1-pentanol only has a single alcohol group.Learn more about Boiling point here:
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Complete Question
Rank the following compounds in terms by increasing boiling point, starting with the lowest boiling point first. I. 1-pentanol II. n-pentane III. 2,2-dimethylpropane IV. (R)-4-hydroxypentanoic acid.
What is the formula for volume usuing density and mass?
Answer:
P= [tex]\frac{M}{V}[/tex]
Explanation:
Which of the following units would be the most appropriate for measuring the volume of a bottle of soda?
Answer: milliliter
Explanation: Generally, the unit used to measure liquid are liter (L) and milliliter (mL). But the volume of liquid in a can of Coca-Cola is commonly measured in mL. Therefore, the correct answer is option b.
Answer:MILLMETER
Explanation:
Identify the approximate bond angles for the following molecules h2s sf2 chcl3 cf4
The approximate bond angles for the given molecules are as follows:
The bond angle of h2s is 92.1°.
The bond angle of SF2 is 98º.
The bond angle of ChCl3 is 109.5º.
The bond angle of Cf4 is 109.5º.
In an molecule, the angle formed between orbitals which contains bonding electrons pairs around the central atom is known as bond angle.
The geometry of a molecule or a compound depends on the bond angles. It is always expressed in degrees.
For example, if a compound has an angle of 180°, it would have linear shape like in the case of CO2. It has a bong angle of 180° and its shape is linear.
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a mixture of 0.0333 g of hydrogen and 0.0165 mol of oxygen in a closed container is sparked to initiate a reaction. how many grams of water can form?
If a mixture of 0.0333 g of hydrogen and 0.0165 mol of oxygen in a closed container is sparked to initiate a reaction. 0.2976 grams of water will be formed.
If the hydrogen reacted has a mass of 0.0333 g. then
Molar mass = m / n
2.016 g/mol = 0.0333 g / n
n = 0.01651785714 mol [tex]H_{2}[/tex]
According to the actual reaction to make water:
[tex]2H_{2} +O_{2} = 2H_{2}O[/tex]
To produce two molecules of water ([tex]H_{2}O[/tex]), two molecules of diatomic hydrogen ([tex]H_{2}[/tex]) must be combined with one molecule of diatomic oxygen ([tex]O_{2}[/tex]) and energy will be released in the process. And to complete the process, one from the reactant side must be in equilibrium with the other or in excess.
If the number of moles of 0.0333 g of [tex]H_{2}[/tex] is 0.0165, then it only needs 0.00826 mol of [tex]O_{2}[/tex] to form 0.0165 mol of water. (oxygen is in excess)
[tex]n_{H_{2} } : n_{O_{2} } :n_{H_{2}O } =[/tex] 2 : 1 : 2
= 0.0165 : 0.00826 : 0.0165
If the water produced is 0.0165 mol, then its mass is:
Molar mass = m / n
18.01528 g/mol = m / 0.01651785714 mol
m = 0.2975738214 g
m = 0.2976 g
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