Ask a question the first things that scientists do when starting a new investigation.
What are scientific practices?Scientific practices, which include things like answering questions, creating and using models, and having arguments, are cognitive, discursive, and social activities carried out in science classrooms with the goal of developing epistemic understanding and appreciation of the nature of science.
Why are the science and engineering practices important?Participating in these activities not only makes students' knowledge more meaningful and deeply ingrained in their worldview, but it also aids them in developing an understanding of the disciplinary and transdisciplinary ideas of science and engineering.
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A student set up the experiment shown below to determine if radish seeds take in oxygen as they germinate. Methylene blue is a chemical that is blue when oxygen is present but is colorless when oxygen is not present. Containers A and B each contained 200 mL of water and 10 drops of methylene blue. Ten radish seeds were added to container A. Container B had no radish seeds.
Ten radish seeds were added to container A. Container B had no radish seeds. The purpose of the container B in this experiment is to serve as a control container.
What is the purpose of the control in the experiment?By using controls, the experimenter can reduce the impact of factors other than the one being researched. This allows us to verify that an experiment is testing what it says it is testing. Controls are important for all sorts of experimental testing, regardless of the subject, and this goes beyond science.
What are the purpose of Methylene blue's function as a markerMethylene blue is usually employed as a redox indicator in analytical chemistry. The solutions of this chemical are blue when in an oxidizing environment, but turn colorless when exposed to a reducing agent.
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At What temperature in kelvin all the elements are solids except for
Answer:
Helium
Explanation:
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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Help plssss i have no clue
What percentage of a radioactive sample remains after four half-lives have passed?
percentage of a radioactive sample that remains after four half-lives have passed is 6.25 %
As radioactive substances are first-order reactions and first-order reactions have a constant half-life and are represented by t1/2. t1/2 = 0.693 / λ
half-life is the time period for the sample to become half of its original concentration.
so for 1 st half-life, the substance will become 100 / 2 =50%
for 2 nd half-life, the substance will become 50 / 2 = 25%
for 3 rd half-life, the substance will become 25 / 2 = 12.5%
for 4 th half-life, the substance will become 12.5 / 2 = 6.25%
percentage of a radioactive sample that remains after four half-lives have passed is 6.25 %
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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.
does anyone know what emerging technology means?
I also want an explanation on what it means
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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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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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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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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order the following types of light from MOST to LEAST energetic: 10^6 Hz, 10^6 m, 10^-6 m , 10^22 Hz, 10^10 m.
The most energetic lights are those with higher frequency and lower wavelengths.
Among frequency (energy order) = 10^22 Hz >10^6 Hz Among wavelength (energy order) = 10^-6 m > 10^6 m > 10^10 mElectromagnetic radiation consists of waves of the electromagnetic area, which propagate via space and bring electromagnetic radiant power. It consists of radio waves, microwaves, infrared, light, ultraviolet, X-rays, and gamma rays. All of these waves shape a part of the electromagnetic spectrum.
Electromagnetic strength is radiant energy that travels in waves at the rate of light. it can additionally be described as radiant electricity, electromagnetic radiation, electromagnetic waves, light, or the motion of radiation. Electromagnetic radiation can switch heat.
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The apparatus in Image A above is used to separate a mixture of ethyl alcohol and water. The mixture is heated in the flask on the left and the ethyl alcohol drips into the flask on the right after condensing in the cooling tube in the middle. Which method was used to separate the mixture?
a. chromatography
b .filtration
c .sorting
d distillation
The method used to separate a mixture of ethyl alcohol and water is distillation. Thus option (d) is true.
What is distillation?Distillation is defined as a process involving the conversion of liquid into vapor that is subsequently condensed back into liquid form.
It is a widely used method for separating the mixture based on difference in conditions required to change the phase of components.
Some of the types of distillation are:
Simple distillation Steam distillation Fractional distillation Vacuum distillationZone distillation etc. and many more are the type of distillation.Thus, the method used to separate a mixture of ethyl alcohol and water is distillation. Thus option (d) is true.
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Your question is incomplete, but most probably your complete question was
The apparatus in Image A above is used to separate a mixture of ethyl alcohol and water. The mixture is heated in the flask on the left and the ethyl alcohol drips into the flask on the right after condensing in the cooling tube in the middle. Which method was used to separate the mixture?
a. chromatography
b .filtration
c .sorting
d distillation
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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What is the frequency of the light emmitted by the atomic hydrogen according to balmers?
The frequency released in transition energy is 4.57 x 10¹⁴ Hz.
We need to know about transition energy to solve this problem. Electrons in a hydrogen atom can move to another level of energy. It is also called a transition. In this process, electrons will absorb or release their energy to move. The transition energy can be determined as
ΔE = E2 - E1
where ΔE is transition energy, E2 is the final state of energy and E1 is the initial state of energy.
The state energy of a hydrogen atom can be calculated by
E = -(13.6) / n² eV
E = h.f
where n is the number of energy states, h is Planck constant (4.136 x 10¯¹⁵ eV/Hz), f is frequency.
From the question above, we know that
n1 = 3
n2 = 2
By substituting the following parameter, we get
ΔE = E2 - E1
ΔE = -(13.6) / n2² - (-(13.6) / n1²)
ΔE = -(13.6) / 3² - (-(13.6) / 2²)
ΔE = 3.4 - 1.51
ΔE = 1.89 eV
Calculate the frequency released
ΔE = 1.89 eV
h.f = 1.89
4.136 x 10¯¹⁵ . f = 1.89
f = 4.57 x 10¹⁴ Hz
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What is the molarity of nacl when 3.46g of nacl is dissolved in water to form 50.0ml of solution?
A chemical species' concentration in a solution, specifically the amount of a solute per unit volume of solution, is measured by its molar concentration.
What is meant by molarity?The amount of a solute per unit volume of a solution, or the concentration of a chemical species in a solution, is expressed as a solute's molar concentration. The most used unit for expressing molarity in chemistry is the number of moles per litre, represented by the unit sign mol/L or mol/dm3 in SI units.
The molarity of a substance refers to how much of it is present in a given volume of solution (M). Molarity is the measure of how many moles of a solute are present per litre of a solution. Molarity is also referred to as a solution's molar concentration. Molarity is the measure of a solute's concentration in moles per litre in a solution (). Molality is the ratio of moles of solute to kilograms of solvent ().
with units of [tex]$\mathrm{mol} \cdot \mathrm{L}^{-1}$[/tex]..
For molarity we take the quotient moles of solute/ volume of solution
And so.... [tex]$\frac{\frac{3.46 \cdot g}{58.44 \cdot \mathrm{g} \cdot \mathrm{mol}^{-1}}}{50.0 \cdot m L \times 10^{-3} \cdot L \cdot m L^{-1}}= \cdot \mathrm{mol} \cdot L^{-1} \ldots$[/tex]
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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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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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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:
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!
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:
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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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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Given the following rate law by what factor does the rate of reaction change if the concentration of y is doubled. rate k[x]2[y]3
If the concentration of y is doubled then rate of reaction will increase by a factor of 4.
What is rate of reaction?The speed at which a chemical reaction moves forward is known as the reaction rate in chemistry. It is frequently described in terms of either the concentration of a reactant that is consumed in a unit of time or the concentration of a product that is generated in a unit of time (amount per unit volume).
The four key variables that determine reaction rate are reactant concentration, the physical state of the reactants, surface area, temperature, and the presence of a catalyst.
For instance, because it happens quickly, wood burning has a high reaction rate, whereas iron rusting has a low reaction rate because it happens gradually.
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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
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.
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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A highly reactive gas is used for refining petroleum
Answer:
Hydrogen
Explanation:
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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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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