Answer: a) 3.72 x [tex]10^{-11}[/tex]
b) 4.5 x [tex]10^{10}[/tex]
Explanation:
a. 0.0000000000372
= 3.72 x [tex]10^{-11}[/tex]
b. 45,000,000,000
= 4.5 x [tex]10^{10}[/tex]
In one or two sentences, explain how Rutherford’s model of an atom changed scientific knowledge and describe the evidence that justified the model.(2 points)
Rutherford’s model of an atom changed scientific knowledge through his assumptions that the atom was made up of a nucleus with positively charged particles.
What is an Experiment?This is defined as a procedure which is carried out by scientists in other to support or refute a hypothesis and also to ascertain its authenticity through various processes.
Rutherford bombarded a piece of gold foil with alpha particles which also has a positive charge and he discovered almost all the particles went through it.
This made him infer that the gold atoms were mostly empty space thereby leading him to propose his model of atom and made scientists discover that there was proton present in the nucleus of an atom which was used as a foundation by others in discovering more information and details about an atom.
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Why is it uncommon for noble gases to form chemical bonds?
Noble gases are exceedingly stable and unlikely to form chemical connections since they have minimal inclination to receive or lose electrons, thanks to the complete valence electron shells of these atoms.
Any one of the seven chemical elements that compose Group 18 (VIIa) of the periodic table is referred to as a noble gas. Helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson are the constituent elements (Og). The noble gases are inflammable, tasteless, colorless, and odorless. The term "noble" has long been used in science and alchemy to describe how resistant metals like gold and platinum are to chemical reactions. As their atomic numbers rise, the abundances of the noble gases fall.
German chemist Friedrich E. Dorn discovered radon for the first time in 1900, and in 1904 it was recognized as a member of the noble-gas family. In 1904, the work of Rayleigh and Ramsay was recognized with Nobel Prizes.
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is corrosion an adverse effect of chemistry
Answer:
yes
Explanation:
corrosion, wearing away due to chemical reactions, mainly oxidation (see oxidation-reduction, oxide). It occurs whenever a gas or liquid chemically attacks an exposed surface, often a metal, and is accelerated by warm temperatures and by acids and salts.
What is the iupac name for the following compound? 3,5-dimethylheptanedioic acid
The iupac name for the following compound is 3,5-dimethylheptanedioic acid
The worldwide organization that represents chemistry and allied disciplines and technology is called the International Union of Pure and Applied Chemistry (IUPAC).
The International Union of Pure and Applied Chemistry (IUPAC) is the foremost expert on chemical language and nomenclature, including the naming of new elements in the periodic table, standardized measurement techniques, atomic weights, and a wide range of other critically analyzed data.
A global standard for naming chemicals is to be established through the IUPAC system of nomenclature in order to improve communication. The system's objective is to assign each structure a distinct and clear name and to associate each name with a distinct and clear structure.
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Which of the following is a quantitative observation?
the smell changed during the chemical reaction
the sound was louder and higher pitch as the siren moved closer
the colors of the lights changed with temperature
The temperature changed from 25°C to 10°C when exposed to ice
Answer:
The temperature changed from 25°C to 10°C when exposed to ice.
Explanation:
Consider the process of diluting 1.2 m nh4cl solution to prepare 1.4 l of a 0.25 m nh4cl solution. determine if each of the follow statement is true or false.
The process of diluting 1.2 m nh4cl solution to prepare 1.4 l of a 0.25 m nh4cl solution. To determine if each of the follow statement is true or false.
The assertion is true.
What is dilution?
By incorporating more solvent, dilution refers to the process of lowering a solute's concentration in a solution. We increase the solvent without increasing the solute in a solution to dilute it. After that, we vigorously mix the resulting solution to make sure that it is evenly distributed throughout.
The assertion is true.
(1) The equation for dilution
A balance of moles of the solute, in this case NH4Cl, is expressed as M1V1 = M2V2.
Calculating dilution involves using the M1V1 = M2V2 equation.The volume of the concentrated solution is denoted by M1, and M1 represents its molarity. The molarity is M2, and the volume of the diluted solution is V2.The conservation of moles principle serves as the foundation for this equation.To learn more about dilution from the given link below,
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If the charges doubled to 2q and electric field is now measured at a distance of two r from the charge, the new measured value of the field will be:________
Using the formula E=(k)(q/r^2),
if q changes to 2q and r changes to 2r,
then, electric field will be:
E = (k) (2q/ 4r^2) = (k)(q/2r^2) = E/2
So, Electric field = E/2
What is Electric Field?An electric field is created when there is an electric charge present in a particular area of space, altering its properties. The physical field that surrounds electrically charged particles and exerts a force on all other charged particles in the field, either attracting or repelling them, is known as an electric field (sometimes referred to as an E-field). It also refers to the charged particle system's physical field. Electric charges and time-varying electric currents are the building blocks of electric fields. Two things can be drawn together or kept apart by an electric charge, which can be positive or negative. Positive-negative things will attract each other if their charges are opposite; positive-positive or negative-negative objects will repel each other if their charges are same.To learn more about Electric field, refer to:
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Is the pressure of an ideal gas directly proportional to its absolute temperature?
The pressure of an ideal gas is directly proportional to its absolute temperature.
How are pressure of an ideal gas and temperature related?
The pressure of an ideal gas is directly proportional to absolute temperature at constant volume.The volume of a gas is also directly proportional to it's absolute temperature at constant pressure.
When a constant volume of gas is held, the pressure of gas increases as the temperature increases. Mathematically it can be expressed as:
P∞T
In order to remove proportionality sign an equal sign is introduced with a proportionality constant 'K',thus the equation becomes
P=KT
On dividing both sides of above equation by T , equation becomes
P/T=K
When a plot of pressure versus temperature is plotted a straight line graph is obtained passing through the origin.
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After an animal takes in nutrients to make needed materials what is the best explanation for what the cell will do next in order to maintain homeostasis
There are three primary ways that the animal cell membrane keeps things in balance: enabling the membrane to flow fluidly, controlling the process by which water moves from a high concentration to a low concentration, and maintaining particular ion concentrations.
Negative feedback loops keep homeostasis in check. Positive feedback loops may be necessary for life to exist even when they actually push the organism further away from homeostasis. The neural and endocrine systems of mammals regulate homeostasis.
For instance, an animal must use the thermoregulation mechanism to control body temperature. Cold-adapted organisms, like the polar bear, have physical characteristics that enable them to survive extreme cold and retain body heat. Fur, feathers, blubber, and fat have structures that help with this kind of insulation.
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Consider the pka of phosphoric acid (h3po4), the catalyst used in this reaction. could acetic acid be used as a catalyst in the reaction instead of phosphoric acid? explain why or why not. (3 pts)
Phosphoric acid has emerged as a novel chiral Brønsted acid catalyst since 2004. Chiral Brønsted acid protonates imines, thereby forming iminium salt bearing a chiral counter anion, and directs the attack of the nucleophile to the iminium salt.
What is Phosphoric acid?With the chemical formula H3PO4, phosphoric acid, also known as orthophosphoric acid, monophosphoric acid, or phosphoric(V) acid, is an inorganic solid that contains phosphorus. Colorless and odorless, phosphoric acid is a substance. In its most common form, an 85% aqueous solution, it appears as a syrupy liquid that is colorless, odorless, and non-volatile. Considering that many fertilizers include it, it is a significant industrial chemical.
Acid makes up the substance. The phosphate ion PO results from the removal of all three H+ ions. H2PO, or hydrogen phosphate, is produced when one or two protons are removed, correspondingly. Organophosphate esters are produced by phosphoric acid.
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Determine the number of protons, neutrons, and electrons present in each of the atoms. cr53 protons: neutrons: electrons: ru103 protons: neutrons: electrons:
Chromium(Cr)53 has 24 protons, 24 electrons and 29 neutrons. Ruthenium(Ru)103 has 44 protons, 44 electrons and 59 neutrons.
In any atom, the atomic number, usually denoted with the letter Z, is always equal to the number of protons. For instance, if an atom has the atomic number 10, it will also have 10 protons. In a neutral atom, the number of protons is equal to the number of electrons. To get the number of neutrons, we subtract the number of protons from the atomic mass. The atomic mass or mass number is the addition of the number of protons and neutrons.
Chromium(Cr) 53In the question, we are only given the atomic mass - 53. To know the number of protons, we need to get the atomic number. On the periodic table, Chromium (Cr) is element number 24 (which is the atomic number) hence, it also has 24 protons. Since the atom is neutral, it will also have 24 electrons. To get the number of neutrons, we subtract 24 from 53, which will give us 29 neutrons.
Ruthenium(Ru) 103Ruthenium (Ru) has the atomic number 44, showing that it has 44 protons. It is also a neutral element, so it will also have 44 electrons. The atomic mass we are given in the question is 103. Therefore, to get the number of neutrons, we subtract 44 from 103, which will give us 59 neutrons.
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What role do bacteria play in creating pimples
Answer: The bacterium Propionibacterium acnes is considered a key player in acne development. Studies have shown that P. acnes uses sebum as a source of energy, and its presence in the pores initiates an immune response that triggers inflammation
Explanation:
A+common+iv+solution+is+0.9%+saline+(nacl+solution).+what+is+the+osmolarity+of+0.9%+saline+mosmoles/l?+the+molecular+weight+of+nacl+is+58.44+g/mole.+pay+attention+to+the+units+that+are+asked+for+here!
An osmolarity of saline solution is 308 mosmol/L.
m(NaCl) = 9 g; the mass of sodium chloride
V(solution) = 1 L; the volume of the saline solution
n(NaCl) = 9 g ÷ 58.44 g/mol
n(NaCl) = 0.155 mol; the amount of sodium chloride
number of ions = 2
Osmotic concentration (osmolarity) is a measure of how many osmoles of particles of solute it contains per liter.
The osmolarity = n(NaCl) ÷ V(solution) × 2
The osmolarity = 0.154 mol ÷ 1 L × 2
The osmolarity = 0.154 mol/L × 1000 mmol/m × 2
The osmolarity of the saline solution = 308 mosm/L.
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Which of the following pieces of lab equipment would be used to measure volume?
Hot plate
Electronic balance
Test tube
Graduated cylinder
Students are conducting an experiment to see what colors different salts turn when they are burned. Jack dares Rebecca to
taste the other salts to see if they taste like regular table salt.
Students are conducting an experiment to see what colors different salts turn when they are burned. Jack dares Rebecca to taste the other salts to see if they taste like regular table salt. She agrees and her mouth starts burning. Rebecca needs to learn how to behave in the class.
When you add salt to a fire, the flame's color will alter. This isn't because the salt is burning; rather, it happens because the flame's heat affects the energy of the salt's electrons, which causes photons of light to be released. When salt is "burned," a golden flame is frequently visible.
High blood pressure is known to increase the risk of stroke and other health issues, and it is also known to increase the chance of burning in salt. High salt consumption has also been linked in several studies to deteriorating brain function. So, if this occurs, plan for brain surgery and a dedicated teacher to assist the student with wiping and peeling bananas.
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A solution of dispersant is made by taking 15.0ml of a 50.0 mg ml -1 solution of tween 80 and mixing it with 50.0 ml of water. calculate the final concentration of the tween 80 in this solution
In terms of grammes per millilitre, the final Randyne concentration was 0.011 g/mL.
Knowing that C1V1 = C2V2 means that C1 and C2 are the concentrations of solutions 1 and 2, respectively.
V1 and V2 are, respectively, the volumes of solutions 1 and 2.
We obtain - mg/mL by substituting the given values.
The final concentration of the solution is 0.11 g/ml.
What is a solution?
A solution is a uniform mixture of two or more components with particles smaller than one nanometer. There are many different types of solutions, such as soda water, salt-and-sugar solutions, and others. In a solution, each component appears as a separate phase.There is particle homogeneity, or a uniform distribution of the particles. This explains why a soft drink bottle's entire contents have the same flavour.
In terms of grammes per millilitre, the final Randyne concentration was 0.011 g/mL.
Knowing that C1V1 = C2V2 means that C1 and C2 are the concentrations of solutions 1 and 2, respectively.
V1 and V2 are, respectively, the volumes of solutions 1 and 2.
We obtain - mg/mL by substituting the given values.
In terms of grammes per millilitre, the final Randyne concentration was 0.011 g/mL.
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A highly reactive gas is used for refining petroleum
Answer:
Hydrogen
Explanation:
Why is sandstone more likely than granite to form an aquifer?
A) The particles in granite are spaced further apart than is sandstone.
B) Sandstone forms where it rains more often.
C) Sandstone is more porous than granite.
D) Granite repels water away from its surface.
How+much+copper+is+contained+in+a+penny+that+is+2.50%+(by+weight)+of+copper?+recall+that+a+penny+has+a+density+of+7.20+g/cm3,+a+diameter+of+19.05+mm+and+a+thickness+of+1.52+mm.
There is 0.078 grams of copper in a penny.
d = 7.20 g/cm³; density of a penny
diameter of a penny = 19.05 mm
thickness of a penny = 1.52 mm
area of a penny = π/ × (d/2)²
area of a penny = 3.14 × (19.05 mm/2)²
area of a penny = 285 mm²
Volume of a penny is the measure of the amount of space occupied by a penny.
volume of a penny = 285 mm² × 1.52 mm
volume of a penny = 433.2 mm³ = 0.4332 cm³
mass of a penny = 0.4331 cm³ × 7.20 g/cm³
mass of a penny = 3.12 g
mass of a copper = 2.50 % × 3.12 g ÷ 100%
mass of a copper = 0.078 g
number of a copper atoms = 0.078 g ÷ 63.54 g/mol × 6.022×10²³
number of a copper atoms = 7.39×10²⁰
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A 100 gram gold nugget contains 5 grams of gold. what is the percentage of gold in the nugget?
A 100 gram gold nugget contains 5 grams of gold.
Then Percentage of gold in the gold nugget is
(5/100)*100 =5%.
What is Percentage ?A % in mathematics is a quantity or ratio that is stated as a fraction of 100 (from the Latin per centum, "by a hundred"). Although the abbreviations "pct.", "pct.", and occasionally "pc" are also used, the percent symbol, "%," is frequently used to indicate it. A % lacks dimensions and has no associated unit of measurement.
If there are 50 male pupils for every 100 overall students in the class, 50 of them will be male. There are 250 male students out of 500 total.
Long before the decimal system was developed, computations were frequently done using fractions that were multiples of one hundred.
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Identify a substance that is not in its standard state.
o3 h
o2
zn
xe
A substance that is not in its standard state is option(b) i.e, H.
The standard state of a substance occurring at the specified temperature and one atmosphere of pressure is the typical condition of a substance occurring in a condensed phase.
Eleven elements are gases in their standard state. Including all noble gases and the halogens fluorine and chlorine (He, Ne, Ar, Kr, Xe, Rn). Hydrogen (H), oxygen, and nitrogen make up the remaining three. All other elements are solid in their native state.
The concept of standard state conditions stipulates that liquids and gases must be pure, solutions must be at 1 M concentration, and 1 atm of pressure is used in STP calculations involving gases that resemble ideal gases. Although the temperature is not stated, most tables gather information at 25 degrees C. (298 K).
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What coefficients are needed to balance the equation for the complete combustion of methane?.
The coefficients needed in the balanced equation for the combustion of methane, [tex]CH_{4}[/tex] + [tex]2O_{2}[/tex] = [tex]CO_{2}[/tex] + [tex]2H_{2} O[/tex], is 1 for methane and carbon dioxide and 2 for oxygen and water.
The coefficients are numerical numbers in front of element or formula in a balanced equation. It shows the number of elements that should react with the number of other elements to produce a particular amount of chemical products.
The combustion reaction of methane is as follows:
[tex]CH_{4}[/tex] + [tex]O_{2}[/tex] = [tex]CO_{2}[/tex] + [tex]H_{2} O[/tex]
To balance this combustion reaction, the number of atoms of each element in the reactant side must be equal to the number of atoms of each element in the product side.
1. Balance C.
[tex]CH_{4}[/tex] + [tex]O_{2}[/tex] = [tex]CO_{2}[/tex] + [tex]H_{2} O[/tex]
2. Balance H.
[tex]CH_{4}[/tex] + [tex]O_{2}[/tex] = [tex]CO_{2}[/tex] + [tex]2H_{2} O[/tex]
2. Balance O.
[tex]CH_{4}[/tex] + [tex]2O_{2}[/tex] = [tex]CO_{2}[/tex] + [tex]2H_{2} O[/tex]
Hence, the coefficients of the balanced equation are 1 for methane and carbon dioxide and 2 for oxygen and water.
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The ph of a 1.79 m solution of hydrocyanic acid (hcn) is 4.477. what is the percent dissociation of hydrocyanic acid under these conditions?
Now, write an equilibrium expression, Ka = [H +][CN -]/[HCN]. Ka = 4.9E-10 = x 2/(0.0620-x). Since the power of the Ka is -10, we can safely assume that the x is small enough to ignore compared to the 0.0620, so it becomes 4.9E-10=x 2/0.0620.
What is equilibrium?Aqueous solutions are ones in which water serves as the solvent. It is commonly represented in chemical equations by adding (aq) to the relevant chemical formula. For instance, Na+(aq) + Cl could be used to represent a solution of table salt (also known as sodium chloride, or NaCl) in water (aq).
The Latin word aqua is the source of the phrase aquatic, which means to be or to consist of water. Water is a common solvent in chemistry since it functions well as a solvent and is also easily accessible. Since water is usually used as the solvent in experiments, unless otherwise mentioned, the word "solution" frequently refers to an aqueous solution.
A solution where the solvent is a liquid is referred to as a "non-aqueous solution."
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Which statement best describes the difference between dissolution and melting? (1 point)
O Dissolution involves the formation of a new substance, while melting involves a state change.
O lonic compounds dissolve, while polar compounds melt.
O Polar compounds dissolve, while ionic compounds melt.
O Dissolution involves a state change, while melting involves the formation of a new substance.
The statement which best describes the difference between dissolution and melting is that dissolution involves the formation of a new substance, while melting involves a state change and is denoted as option A.
What is Dissolution?This is the process in which a solute dissolves in a solvent such as water to form a solution thereby resulting in a new substance being created.
Melting on the other hand is the process in which a solid phase is changed into a liquid phase with the application of heat which makes the atoms move more freely.
This is therefore the reason why option A was chosen as the most appropriate choice.
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The reaction of 5.0 g of cuso4 with excess sodium hydroxide produced 2.6 g of cu(oh)2. what percent yield of cu(oh)2 was obtained?
percent yield of Cu (OH)2 is 85%
CuSO4 + 2 NaOH >>> Cu (OH)2 + Na2SO4
What is Cu Oh 2's theoretical yield?Cu (OH)2 theoretical yield = 0.09 mol NaOH x 1 mol Cu (OH)2 = 4.39 g Cu (OH)2 = 4 g Cu (OH)2 calculate percent yield Cu (OH)2 / 2 mol NaOH x 97.6 g Cu (OH)2/mol = 4.39 g Cu (OH)2 = 4 g Cu (OH)2.calculate the percentage yield
First, ensure that both weights are in the same units.Divide your experimental yield by your theoretical yield.To calculate the percent yield, multiply this value by 100.The actual yield is the amount of product produced from a given amount of reactant. The percent yield is calculated by dividing the actual yield by the theoretical yield and multiplying by 100%. Percent yield = actual yield / theoretical yield multiplied by 100%.Since 65.13% of the mass of Cu (OH)2 is due to copper the mass of copper in 400 grams of Cu (OH)2 can be calculated by the equation below.
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Help plssss i have no clue
At What temperature in kelvin all the elements are solids except for
Answer:
Helium
Explanation:
Which of the following example demonstrates the reversibility of a chemical change?
A. Refreezing carbon dioxide gas into dry ice
B the rotting of eggs
C. dehydrating sugar water
D. recharging batteries
The statement that shows an example that demonstrates the reversibility of a chemical change is rotting of eggs (option B).
What is a chemical change?A chemical change is any process in which reactants are changed into products by the breaking or creation of chemical bonds.
Chemical changes are opposed to physical change, which only affects the form of a chemical substance, but not its chemical composition.
Examples of chemical changes are as follows:
Burning of paper and log of wood.Digestion of food.Boiling an egg.Chemical battery usage.Electroplating a metal.Baking a cake.Milk going sourTherefore, it can be said that rotting process of an egg is an example of a reversible chemical change.
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Answer:
Recharging batteries.
I just took the quick check
Explanation:
If your here for the Physical vs. Chemical Change Quick check for Connexus, here are the answers.
1- Dry ice becoming vapor
2-iron (Fe) reacting to water((H2O)) and oxygen(O) to form iron oxide(Fe2O3)
3-conduct a test to determine the chemical makeup of the molecules
4-Atoms of one or more substances rearrange into a new substance.
5-recharging batteries
I took the quick check, and these were the answers!!
Hope this helps someone!
Tom adds solid sodium hydroxide to a flask of water at room temperature. After he stirs the water, some of the
sodium hydroxide dissolves, however, a small amount of sodium hydroxide still remains at the bottom of the flask.
He heats the flask of sodium hydroxide and water for 10 minutes, and the sodium hydroxide on the bottom of the
flask disappears. How does heating the water cause the remaining sodium hydroxide to disappear?
Answer: It has a lower boiling/melting point than the water
What is the most abundant isotope of Iridium (Ir)?
Question 1 options:
Iridium-77
Iriduium-192
Iridium192.22
The most abundant isotope of iridium is Iriduium-192.
What is the most abundant isotope?An element is composed of isotopes. The isotopes of an elements have different mass numbers but the same atomic number. These difference in the mass number is caused by differences in the number of neutrons.
Hence, we can see that all elements do have isotopes. The chemical and physical properties of isotopes may be the same save that the rate of reaction of the individual isotopes may slightly differ. The most abundant isotope has the highest length in the mass spectrum.
We can see that there are three isotopes of Iridium that are common. The most abundant isotope of iridium is Iriduium-192.
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