name the two criteria that is used to determine if a substance is pure or not
Answer:
Melting and Boiling Point Determination
The physical properties of a substance can be used to establish its purity. These properties include the melting point and boiling point. Different substances tend to have different melting and boiling points, and any pure substance will have a specific melting and boiling point.
What is an electrolytic cell?
Answer:
An electrolytic cell is a cell that converts electrical energy into chemical energy.
Any device in which electrical energy is converted to chemical energy or vice versa is referred to as an electrolytic cell. A typical cell consists of two metallic or electronic conductors held apart and in contact with an electrolyte, which is usually a dissolved or fused ionic compound.
What is an electrolytic cell ?An electrolytic cell is a type of electrochemical cell that uses an external source of electrical energy to force a chemical reaction that would not occur otherwise. A voltage applied between the cell's two electrodes, an anode and a cathode immersed in an electrolyte solution, serves as the external energy source.
Electrons in the form of an electric current are deliberately pumped through the chemicals in the section to induce an oxidation-reduction reaction. An electrolytic cell is a setup used to electrolytically decompose water into hydrogen and oxygen.
Electrochemical cells that generate an electric current are known as voltaic or galvanic cells, whereas those that generate chemical reactions, such as electrolysis, are known as electrolytic cells.
Thus, Any device in which electrical energy is converted to chemical energy or vice versa is referred to as an electrolytic cell.
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what is the chemical equation for methamphetamine
Answer:
C10H15N is the chemical equation for methamphetamine
pls help me on this it's about acceleration
Answer:
1: A b/c the table is showing that each different surface resulted in different time for acceleration.
2: D b/c the if the same force is applied to two different masses, the smaller masses would be impacted more and move faster. The larger an object is, then the greater the force you will need for it to move the same distance as the smaller masses.
Which of the following is an ether?
A)
B)
C)
D)
#3. How does a fever aid an immune response?
Answer:
it can tell and show what pathogen is in you as well what type and mutation so then your body can fight back and remember the genetic dna so then you will be immune in some way.
Explanation:
Question;
How does a fever aid an immune response?
Answer:
One type of immune cell jumps into the fray after body temperature rises, according to experiments in mice. A fever fights infection by helping immune cells to crawl along blood-vessel walls to attack invading microbes
2 CuCl2 + 4 KI → 2 CuI + 4 KCl + I2
When 13.5 moles of CuCl2 reacts with 19.86 moles of KI, how many moles of I2 are formed?
Answer: 6.75 moles
Explanation:
This is a simple stoichiometry proboe. that I would set up like this:
(13.5 moles CuCI2) (1 mol I2 / 2 moles CuCi2)
That means you all you have to do for this problem is divide by 2 and cancel out the unit moles CuCI2, which leaves you with 6.75 moles I2.
Hope this helps :)
How many particles are in 4g of NaCl? (1mol of NaCl = 58g) – 2 step conversion
Answer:
4.16 * 10²⁴ particles
Explanation:
1. We convert from grams to moles
4 g NaCl / 58 g of NaCl = 0.0689655172 moles
-> 0.0690 moles
2. Now we will convert from moles to particles by multiplying by avogadro's number..
0.0690 * 6.022 *10²³ = 4.15518 * 10²⁴ particles or 4.16 * 10²⁴ particles
Learning ObjectivesIn this activity, you'll practice determining the limiting reagent for a reaction between silver nitrate and copper metal. In part 1 you'll make the measurements you need so you can predict the amount of silver produced. In part 2 you'll be able to measure how much silver was actually produced. Finally you will be asked to consider possible reasons for the discrepancy.Part 1: Describe the ReactionIn this activity, you will be observing a reaction where copper and silver nitrate react to form copper (II) nitrate and silver.1.Write a balanced chemical equation for this reaction.2AgNO3 Cu -> 2Ag Cu(NO3)2Score: 0 / 12.
Answer:
Explanation:
The balanced chemical reaction equation is;
2AgNO3(aq) + Cu(s) -> 2Ag(s) + Cu(NO3)2(aq)
When we balance chemical reaction equations, we ensure that the number of atoms of each element on the left hand side of the reaction equation is exactly the same number of atoms of each element on the right hand side of the reaction equation.
Let us consider this reaction;
There are two atoms of Ag on both sides of the reaction equation
There are six atoms of O on both sides of the reaction equation
There are 2 atoms of N on both sides of the reaction equation
There is one atom of Cu on both sides of the reaction equation.
Hence, the reaction equation is balanced.
it’s an astronomy question
Which method would you use to obtain the distance to each of the following? An asteroid crossing Earth's orbit B. A star astronomers believe to be no more than 50 light-years from the Sun A tight group of stars in the Milky Way Galaxy that includes a significant number of variable stars D. A star that is not variable but for which you can obtain a clearly defined spectrum
Answer:
A. Radar would be the best tool for measuring distances to objects in the solar system.
B. A parallax measurement would be best for this nearby star.
C. Cepheids or RR Lyraes would be useful for determining the distance to this cluster.
D. The method using the H-R diagram and getting a spectrum to determine the luminosity class of the star.
How can scientists make orange juice smell pleasant?
The compound cobalt (II) sulfate forms a hydrate with seven water molecules per formula unit. What are the name and formula of the hydrate
Answer: The formula of the hydrate will be [tex]CuSO_4.7H_2O[/tex] and the name of the compound is copper sulphate heptahydrate.
Explanation:
Water of crystallisation is the number of water molecules that combine chemically in definite molecular proportion with the concerned salt in the crystalline state.
The formula of the hydrate will be [tex]CuSO_4.7H_2O[/tex] and the name of the compound is copper (II) sulphate heptahydrate as there are 7 molecules of water.
Please help it really important, I will mark brainliest please
Answer:
S0rRy i d0nT kn0w fRenCh
During radioactive decay, the __________ isotope decays into a ____________ isotope that has a different ___________________ number.
Answer: Please find answer in explanation column
Explanation:
During radioactive decay, the __unstable ________ isotope decays into a _stable ___________ isotope that has a different ____proton _______________ number
Or
During radioactive decay, the _ unstable parent nuclide ________ isotope decays into a _stable daughter nuclide ___________ isotope that has a different ____proton _______________ number.
There are 3 types of radioactive decay;alpha, beta and gamma, Of which the above clearly explains the beta decay. In beta decay, the unstable isotope having excess neutrons will undergo a beta decay emitting a beta particle.( ⁰₋₁e) causing the nucleus to loose a neutron but gain a proton.
Some heavy unstable isotopes which undergo radioactive (beta decay ) to become stable isotopes are phosphorus-32, strontium-90, iodine-131
Using Strontium 90 as an example , we have
⁹⁰₃₈St ----->⁹⁰₃₉Y + ⁰₋₁e
Strontium an unstable isotope undergoes a beta radioactive decay to form Yttrium.
The section "The Necessary Resources" introduces the idea that communism was a reaction to capitalism.The section "Karl Marx And Communism" develops this idea by ........(A)explaining how Marx believed the goals of communism would fix the problems of capitalism.(B)describing where Marx studied capitalism to research ideas for his book on communism.(C)explaining why Marx thought capitalism made rich people richer and hurt workers.(D)describing who Marx inspired to follow the ideas in his new system called communism.
Answer:
(A)explaining how Marx believed the goals of communism would fix the problems of capitalism.
Explanation:
In the section, "The Necessary Resources", after listing the four resources needed for an economic system to thrive, the author explained the practice of capitalism in the mid-1800s, where people owned private property and how Karl Marx and Friedrich Engels came up with the notion that capitalism did not allow for the fair distribution of resources.
In the section, "Karl Marx and Communism", further explanation was provided as to how Marx felt that capitalism caused a gap between the rich and the poor, how that system was unfair to poorly paid workers and how communism will soon replace capitalism.
How many moles are in a solution if I have 2.21 M of NaCl in 1.14 L?
A.1.12 mol
B.2.52 mol
C.4.15 mol
D.7.89 mol
Answer:
The correct answer is B.2.52 mol
Explanation:
The molarity of a solution (M) expresses the number of moles of solute there is in 1 liter of solution. If we have the molarity (M) and the volume in liters (L), we simply multiply M x V to obtain the moles, as follows:
M = 2.21 = 2.21 moles/L
V = 1.14 L
M x V = 2.21 moles/L x 1.14 L = 2.5194 moles ≅ 2.52 moles
The osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant R. Suppose the osmotic pressure of a certain solution is measured to be 20.atm at an absolute temperature of 321.K. Write an equation that will let you calculate the molarity c of this solution. Your equation should contain only symbols. Be sure you define each symbol other than R.
Answer:
20 atm / (R . 321 K . i) = M
Explanation:
Osmotic pressure is a colligative property which is determined by the solute.
Solutes over solutions, can increase the osmotic pressure which is calculated like this:
P = M . R . T
where P is pressure, M is molarity, R the Universal Constant Gases and T, the absolute Temperature. We also have to consider the Van't Hoff factor, i, numbers of ions dissolved. Ionic salts determine more osmotic pressure than organic compounds, where i = 1. Then, the complete formula is:
π = M . R . T . i
To determine molarity, osmotic pressure divide all the terms:
20 atm / (R . 321 K . i) = M
R = 0.082 L.atm/mol.K
If you see all the units in R, they will be cancelled, so finally the answer will be mol/L, which is molarity. The i term has no unit!.
Choose the combination of factors that creates fog. Record the description of the factors in the Student Guide,
Relative Humidity
Air Temperature
Air Pressure
Check
Pause
Answer:
Relative Humidity
Air Temperature
Explanation:
Relative humidity and air temperature are the factors that creates fog. When the moist and warm air makes contact with the cooler air, water vapor condenses due to low temperature of that region that causes for the formation of fog. So we can say that relative humidity and air temperature are the main factors for the formation of fog in that region.
Answer:
High Cold High
Explanation:
HELP ILL MARK BRAINLIEST
What makes a White Dwarf Star different from Main Sequence, Giant, and Supergiant stars?
Answer:
Formation. Main-sequence stars, including the sun, form from clouds of dust and gas drawn together by gravity. ... The core that is left behind will be a white dwarf, a husk of a star in which no hydrogen fusion occurs. Smaller stars, such as red dwarfs, don't make it to the red giant state.
Explanation:
Which of the following sources could not be used to obtain the DNA of a person lost in a mass disaster? used and unwashed clothing or bed sheets food found in the victim's refrigerator sunglasses regularly used by the person a toothbrush used by the person
Which of the following sources could not be used to obtain the DNA of a person lost in a mass disaster?
used and unwashed clothing or bed sheetsfood found in the victim's refrigeratorsunglasses regularly used by the persona toothbrush used by the personAnswer :food found in the victim's refrigerator could not be used to obtain the DNA of a person lost in a mass disaster.
So, correct answer is 2nd one.
You explored the relationship between molarity, the number of moles, and solution volume. However, when you prepare a solution, you are unable to directly measure the number of moles of solute. Instead, you can mass the solute and convert between the number of moles and mass using the molar mass of a substance as a conversion factor. The molar mass of a substance can be calculated based on its molecular formula; otherwise, it can be calculated from the mass and number of moles as follows: Molar Mass = Mass solute (in g)Moles solute In order to prepare a certain volume of solution with a desired concentration, you would need to determine the required mass of solute. What mass of CaCl2 would you need to prepare a 100. mL solution at a concentration of 0.240 M ? Express the mass in grams to three significant figures.
Answer:
2.64gram
Explanation:
Molarity, which refers to the molar concentration, is calculated thus:
Molarity = number of moles (n) ÷ volume (L)
According to the question, volume = 100 mL, molarity = 0.240 M.
Since 1L = 1000mL
100 mL = 100/1000
= 0.1L
Hence;
0.240 = n/0.1
n = 0.1 × 0.240
n = 0.024mol
Mole = mass/molar mass
Molar mass of CaCl2 = 40 + 35.5(2)
= 40 + 71
= 111g/mol
mass = molar mass × mole
mass = 110 × 0.024
Mass = 2.64gram
What are the three types of diagrams in science? This if eight grade science
Answer: bar graph, circle graphs, line graphs
Explanation:
36) Which element is larger?
Potassium (K)
or
Calcium (Ca)
37) Which element is larger?
Magnesium (
Mg)
or
Calcium (Ca)
38) Which element is more electronegative?
Oxygen (0)
or
Fluorine (E)
39) Which element is more electronegative?
Chlorine (CD)
or
Fluorine (F)
40) Which element has a higher ionization energy?
Silicon (SI)
or
Phosphorus (P)
41) Which element has a higher ionization energy?
Nitrogen (N)
or
Phosphorus (P)
42) Which element is more reactive?
Sulfur (S)
or
Chlorine (CI)
43) Which element is more reactive?
Potassium (K)
or
Calcium (Ca)
36 ) Potassium
37 ) Calcium
38 ) fluorine
39 ) fluorine
40 ) Phosphorus
41 ) Phosphorus
42 ) Sulphur
43 ) Sodium
neptune has an average distance to the sun of 30.06 au in two or more complete sentences explain how to calculate the orbital period of neptune
Answer:
As per Kepler's law we know that \frac{T_1^2}{T_2^2} = \frac{R_1^3}{R_2^3}T22T12=R23R13as we know that for earth the time period is 1 year and its distance is 1 AUnow from above formula we can saylet the time period of Neptune is T and its distance is given as R = 30.06 AUnow we will have\frac{1^2}{T^2} = \frac{1^3}{30.06^3}T212=30.06313by rearranging the above equation we haveT^2 = (30.06)^3T2=(30.06)3T = 164.8 yearsT=164.8yearsso it will have time period of 164.8 yearsGiven the atomic mass of select elements, calculate the molar mass of each salt.
Element Molar mass
(g/mol)
Beryllium (Be) 9.012
Magnesium (Mg) 24.31
Cobalt (Co) 58.93
Cadmium (Cd) 112.41
Bromine (Br) 79.90
Match the numbers to the appropriate blanks in the sentences below. Make certain each sentence is complete before submitting your answer.
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1. The molar mass of MgBr2 is The molar mass of M g B r 2 is blank..
2. The molar mass of BeBr2 is The molar mass of B e B r 2 is blank..
3. The molar mass of CoBr2 is The molar mass of C o B r 2 is blank..
4. The molar mass of CdBr2 is The molar mass of C d B r 2 is blank..
Is water made of plant cells or animal cells
•plant
•animals
•niether
Answer:
i think niether
Explanation:
Cromium and tantalum both have the BCC crystal structure, and Ta forms a substitutional solid solution for all concentrations at room temperature. Compute the unit cell edge length for a 26 wt% Cr - 74 wt% Ta alloy. The room-temperature density and atomic weight of Cr are 7.19 g/cm3 and 52.00 g/mol, the room-temperature density and atomic weight of Ta are 16.6 g/cm3 and 180.95 g/mol, respectively.
Answer:
0.3139 nm
Explanation:
First of all, let's Calculate the average density of the Cr −Ta alloy;
Formula to get it is;
ρ_avg = 100/[(C_cr/ρ_cr) + (C_ta/ρ_ta)]
We are given;
C_cr = 26%
C_ta = 74%
ρ_cr = 7.13 g/cm³
ρ_ta = 16.6 g/cm³
Thus;
ρ_avg = 100/[(26/7.13) + (74/16.6)]
ρ_avg = 12.34 g/cm³
Similarly, let's Calculate the average atomic weight;
A_avg = 100/[(C_cr/A_cr) + (C_ta/A_ta)]
We are given;
A_cr = 52 g/mol
A_ta = 180.95 g/mol
Thus;
A_avg = 100/[(24/52) + (74/180.95)]
A_avg = 114.88 g/mol
Formula for the volume of the unit cell is;
V = n(A_avg)/(N_A × ρ_avg)
Where;
n is number of atoms in the cell which in this case = 2
N_A is avogadro's number = 6.022 × 10^(23)
Thus;
V = (2 × 114.88)/(6.022 × 10^(23) × 12.34)
V = 30.92 × 10^(-24) cm³
Length of the unit cell edge length is given by the formula;
a = ∛V
Thus;
a = ∛(30.92 × 10^(-24))
a = 0.00000003139 cm
Converting to metre, we have;
a = 0.3139 × 10^(-9) m = 0.3139 nm
K2HPO4 is a highly water-soluble salt. It can be used as a buffering agent, food additive, or
fertilizer. The neutralization of phosphoric acid with potassium hydroxide can be used to form
potassium hydrogen phosphate.
H3PO4 + 2KOH K2HPO4 + 2H2O
100 g of phosphoric acid (H3PO4) is reacted with excess potassium hydroxide. The final mass
of K2HPO4 produced is found to be 163 g.
What is the percent yield?
Answer:
91.7%
Explanation:
The percent yield when it could be used as a buffering agent should be considered as the 91.74%.
Calculation of the percent yield:Since we know that
Number of moles = Mass in gram / Molar mass
And,
Molar mass of H3PO4 = 97.994 g/mol
So,
Number of moles of H3PO4
= 100 g / 97.994 g/mol
= 1.02 mol
Now
Molar mass of K2HPO4 = 174.2 g/mol
So,
Theoretical yield of K2HPO4 = 174.2 g/mol * 1.02 mol
= 177.684 g
So finally
Percent yield = Actual yield * 100 / Theoretical yield
= 163 g * 100 / 177.684 g
= 91.74%
hence, The percent yield when it could be used as a buffering agent should be considered as the 91.74%.
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Which represents the overall (net) reaction of this mechanism: step 1: H2O2 + I- → H2O + OI- step 2: H2O2 + OI- → H2O + O2 + I- Note that I- acts as a catalyst in this reaction.
A. 2H2O2 → 2H2O + O2
B. H2O2 → H2 + O2
C. H2O2 + I- → OI- + H2O
D. H2O2 + OI- → H2O + O2 + I-
Answer:
A. 2H₂O₂ → 2H₂O + O₂
Explanation:
1. H₂O₂ + I⁻ → H₂O + OI⁻2. H₂O₂ + OI⁻ → H₂O + O₂ + I⁻If we make a net sum of both reactions, we're left with:
H₂O₂ + I⁻ + H₂O₂ + OI⁻ → H₂O + OI⁻ + H₂O + O₂ + I⁻Grouping species:
2H₂O₂ + OI⁻ + I⁻ → 2H₂O + OI⁻ + O₂ + I⁻There is OI⁻ at both sides, so it is eliminated -same goes for the catalyst, I⁻-.
2H₂O₂ → 2H₂O + O₂Thus the answer is option A.
Name this branched alkane shown in Figure 18-1.
Answer:
3–ethyl–2,2–dimethylhexane
Explanation:
To name the compound given in the question above, do the following:
1. Determine the parent name by determining the longest continuous carbon chain. In this case, the longest continuous carbon chain is 6. Hence, the parent name is Hexane.
2. Identify the substituent group attached to the compound. In this case, we have one ethly group (–CH₂CH₃) and two methyl groups (–CH₃)
3. Locate the position of the substituents by giving them the lowest possible count. In this case,
The two methyl groups (–CH₃) are located at carbon 2
The ethly group (–CH₂CH₃) is located at carbon 3.
4. Combine the above to obtain the name of the compound.
The name of the compound is:
3–ethyl–2,2–dimethylhexane