Point to be present exactly at midway between center and circumference of circle (let’s say radius = r) should lie at circumference of circle of radius r/2.
Favorable outcome = 2*pi*r/2
Total outcome = Point can be anywhere inside the circle of radius r = Area of circle = pi * r * r
Probability = (2*pi*r/2) / pi * r* r = 1/r.
Not completely sure about correctness . Waiting for comments to verify.
Which of the following describes a spectrum?
A. A measurement of the energy associated with an electron
transition
B. A piece of glass that causes light to be divided into different
colors
C. A range of wavelengths or frequencies of electromagnetic
radiation
D. A list of the quantum numbers assigned to a particular electron
Answer: The Answer would be C
Explanation: A spectrum is a Range of Wavelengths and Frequencies of Electromagnetic Radition.
The statement that describe spectrum is a range of wavelengths or frequencies of electromagnetic radiation.
What is Spectrum?Spectrum arrangement or electromagnetic radiations base on their wavelength and frequency which can be visible light, ultraviolet, and infrared light. An instrument that is use for visual observation of spectra is called a spectroscope.
Therefore, The statement that describe spectrum is a range of wavelengths or frequencies of electromagnetic
radiation.
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Im stuck on these two questions anyone have the right answer?
A chlorine atom becomes stable by having 8 valence electrons by
A losing one electron
B gaining one electron
C gaining 3 electrons
D losing seven electrons
Pick the correct statement about the pure water. Group of answer choices Pure water contains no ions. Pure water contains equal amounts of hydroxide [OH-] and hydronium [H3O ] ions. Pure water contains larger amounts of hydroxide [OH-] than hydronium [H3O ] ions. Pure water is an electrolyte. Pure water contains smaller amounts of hydroxide [OH-] than hydronium [H3O ] ions.
Answer:
Pure water contains no ions. TRUE
Pure water contains equal amounts of hydroxide [OH-] and hydronium [H3O+ ] ions. TRUE
Explanation:
This is the equilibrium for pure water:
2H₂O ⇄ H₃O⁺ + OH⁻ Kw
We see that pure water has no Ions. Pure water can not conduct electricity.
Generally ionized water comes from the water tap.
Another feature of pure water is pH.
Definetely pH of pure water is : 7
As pH = 7, [H₃O⁺] = 1×10⁻⁷
Then, [OH⁻] = 1×10⁻⁷
This is reazonable because Kw is 1×10⁻¹⁴ and Kw = [H₃O⁺] . [OH⁻]
In conclussion:
Pure water contains no ions. TRUE
Pure water contains equal amounts of hydroxide [OH-] and hydronium [H3O+ ] ions. TRUE
Pure water contains larger amounts of hydroxide [OH-] than hydronium [H3O+] ions. FALSE
Pure water is an electrolyte. FALSE
Pure water contains smaller amounts of hydroxide [OH-] than hydronium [H3O ] ions. FALSE
Which of the following is the correct set up AND answer to convert 6.25 x
1032 atoms of Copper to grams of Copper?
Answer:
Explanation:
How many mols do you have?
1 mol = 6.02 * 10^23 atoms
x mol = 6.25 * 10 ^32 atoms
1/x = 6.02*10^23 / 6.25 * 10^32 Cross multiply
6.02 * 10^23 * x = 1 * 6.25 * 10^32 Divide by 6.02 * 10^23
x = 6.25 * 10*32/ 6.02 ^10^23
x = 1.038 * 10^9 mols which is quite large.
Find the number of grams. (Use the value for copper on your periodic table. I will just use an approximate number.)\
1 mol of copper = 63 grams.
1.038 * 10^9 mols of copper = x
1/1.038 * 10^9 = 63/x Cross multiply
x = 1.038 * 10^9 * 63
x = 6.54 * 10^10 grams of copper.
(1.21 x 10^-3 + 1.3 x 10^-3) x 6.453 x 10^2 =
Answer:
1.61
Explanation:
A chemist adds 255 .0 mL of a M copper(II) sulfate solution to a reaction flask. Calculate the mass in grams of copper(II) sulfate the chemist has added to the flask. Round your answer to significant digits.
Answer:
The correct answer is 40.7 grams.
Explanation:
Based on the given information, the volume of copper sulfate added to the solution is 255 ml or 0.255 L. The molarity of copper sulfate is not given, so let us consider it to be 1 M, which can also be written as 1 moles per liter.
The moles of copper sulfate can be determined by using the formula,
Moles = Molarity * Volume in Liters
Moles of CuSO4 = 1 moles/Liter * 0.255 L
Moles of CuSO4 = 0.255 moles
The mass of CuSO4 added in the solution will be,
Mass of CuSO4 = Moles * Molecular mass
= 0.255 moles * 159.609 grams per mole
= 40.7 grams.
explain the trend in boling point of alcohols in their homologous series
Explanation:
The boiling point of alcohols also increase as the length of hydrocarbon chain increases
The boiling point of alcohols also increase as the length of hydrocarbon chain increases.
Why boiling points of alcohols increases as the length of hydrocarbon chain increasesSince, boiling point depends upon type of bonds present in the molecules.If molecules have hydrogen bonding then boiling point is higher than others because hydrogen bond is stronger bond.So, higher energy or temperature required to break these bond or overcomes the inter molecular force of attraction.Since, alcohol contains hydrogen bonding. So, its boiling points are higher as compare to other compounds.Since, boiling points is also directly proportional to molar mass of molecules. So, molecule have higher molar mass has comparatively high boiling point.Example: An alcohols with lower hydrocarbon chain has lower boiling points as compare to alcohols with higher hydrocarbon chain.To learn more about alcohols,
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What mass of oxygen will react with 2.64 g of magnesium?
2Mg(s) + O2(g) → MgO(s)
Answer:
[tex](24 \times 2) \: g \: of \: magnesium \: reacts \: with \: (16 \times 2) \: g \: of \: oxygen \\ 2.64 \: g \: of \: magnesium \: will \: react \: with \: ( \frac{2.64 \times 16 \times 2}{24 \times 2} ) \: g \\ = 1.76 \: g \: of \: oxygen[/tex]
For the reaction represented by the equation 2H2 + O2→ 2H2O, how many grams of water can be produced from 6.0 grams of O2?
Answer:
a. 6 grams
b. 108 grams
c. 2 grams
d. 54 grams
What is predicted to happen if the permafrost in the Arctic melts?
Answer: It is causing erosion, landslides, and craters. If this keeps up the ice in the artic will eventually be gone
Explanation:
If atoms are electrically neutral then how do they form bonds?
Answer:
The nucleus contains neutrons and protons; protons carry the positive charge. The shells contain electrons which carry the negative charge. So, how can the atom be changed. ... Covalent bonds are electrically neutral because they are not formed due to the transfer of electrons but sharing of electrons.Explanation:
Hope it helps ^-^
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Answer:
When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges (the electrons) and positive electric charges (the protons). The total electric charge of the atom is therefore zero and the atom is said to be neutral. ... Chemically, we say that the atoms have formed bonds
ok so i need a reasoning on What evidence have you discovered to explain how the curve of Earth’s surface affects temperatures on Earth?
4- 4110 kg of R-134a at 300 kPa fills a rigid container whose volume is 14 L. Determine the temperature and total enthalpy in the container. The container is now heated until the pressure is 600 kPa. Determine the temperature and total enthalpy when the heating is completed.
The correct question is: 10 kg of R-134a at 300 kPa fills a rigid container whose volume is 14 L. Determine the temperature and total enthalpy in the container. The container is now heated until the pressure is 600 kPa. Determine the temperature and total enthalpy when the heating is completed.
Answer: The temperature is [tex]21.6^{o}C[/tex] and total enthalpy when the heating is completed is 300 kJ.
Explanation:
Given: Mass = 10 kg
Volume = 14 L
Final pressure = 600 K
First, convert volume from L to [tex]m^{3}/kg[/tex] as follows.
[tex]v_{1} = \frac{14 \times 10^{-3}}{10}\\= 0.0014 m^{3}/kg[/tex]
According to the R-134a tables at 300 kPa and [tex]0.0014 m^{3}/kg[/tex].
[tex]h_{1}[/tex] = 54.6 kJ/kg
[tex]T_{sat}[/tex] = 0.7 C
[tex]u_{1}[/tex] = 54.1 kJ/kg
Now, at the state 2 [tex]p_{2}[/tex] = 600 kPa and [tex]v_{2} = v_{1} = 0.0014 m^{3}/kg[/tex]
This means that the final temperature at state 2 is [tex]T_{2} = T_{sat} = 21.6^{o}C[/tex]
Hence, the change in enthalpy is calculated as follows.
[tex]\Delta H = m(h_{2} - h_{1})\\= 10(84.6 - 54.6)\\= 300 kJ[/tex]
The first law is applied to transfer the heat transfer as follows.
[tex]Q = m(u_{2} - u_{1})\\= 10(83.8 - 54.1) kJ\\= 297 kJ[/tex]
Thus, we can conclude that the temperature is [tex]21.6^{o}C[/tex] and total enthalpy when the heating is completed is 300 kJ.
(1 point) Which compound produces the greatest number of ions when one mole of it is dissolved in water
The question is incomplete, the complete question is;
Which produces the greatest number of ions when one mole dissolves in water? a. NaCl b. NH4Cl c. NH4NO3 d. Na2SO4
Answer:
Na2SO4
Explanation:
If we consider the compounds listed in the options one after the other;
NaCl produces two moles of ions in solution
NH4Cl produces two moles of ions in solution
NH4NO3 produces two moles of ions in solution
Na2SO4 produces three moles of ions in solution
We can see that Na2SO4 produces the greatest number of ions when one mole of the substance is dissolved in water, hence the answer above.
Sodium hydroxide, NaOH, is a strong base that is sometimes used as a cleaning agent since it can be used to dissolve proteins, grease, oils, and fats. Rank the following in increasing order of their molarity. Rank from lowest to highest.
a. 6.625 g NaOH dissolved in 250. mL of water
b. 63.0 g of NaOH dissolved in 1.00 L of water
c. 8.00 g of NaOH dissolved in 500. mL of water
d. 0.0530 of NaOH in 100 mL of water
Answer:
Rank from lowest to highest - c<a<d<b
Explanation:
Molarity is basically the moles of the solute dissolved in a solvent. Molar mass of NaOH = 39.997 g/mol
a) 6.625 g NaOH dissolved in 250. mL of water
Molarity = 6.625 grams */( 0.250 *39.997) g/mol = 0.66
b) 63.0 g of NaOH dissolved in 1.00 L of water
Molarity = 63 grams */( 1 *39.997) g/mol = 1.575
c) 8.00 g of NaOH dissolved in 500. mL of water
Molarity = 8 grams */( 0.5 *39.997) g/mol = 0.331
d) 0.0530 of NaOH in 100 mL of water = 0.53
Rank from lowest to highest - c<a<d<b
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In this lab you will need to prepare solutions using dilutions. Starting with the stock 0.300 M NaOH solution, how would you prepare a 0.100 M NaOH solution (using 0.300 M NaCl as the diluent)
Answer:
1/3 dilution : 1 volume of stock solution + 2 volumes of diluent
Explanation:
Concentrated solution = 0.300 NaOH
Diluted solution = 0.100 NaOH
The dilution factor is : 0.100/0.300 = 1/3
Thus, we have to dilute three times the stock solution. For this, we take 1 volume of stock solution and then we add 2 volumes of diluent. As result, we will have 1 volume of stock solution in a total of 3 volumes. For example, we take 1 mL of 0.300 NaOH and then we add 2 mL of diluent (0.300 NaCl). The final concentration after dilution will be:
Cd = 0.300 M x 1 mL/3 mL = 0.100 M
why the environment in most communities continue to be dirty 2×8
80. When water forms ice, hydrogen bonds around a water molecules are at ... apart.
1.
30 °C
2. 45 °C
3.
90 °C
4.
180 °C
5. 35 °C
6. I do not know.
N
Answer:
6
Explanation:i dont know
WILL GIVE BRAINLIEST TO FIRST ANSWER
picture ⬆️
Answer: A Molecular Approach, 2/e. Mole ratio. 2 mol C4H10 : 13 mol O2 : 8 mol CO2 : 10 mol H2O. ❖ 2 molecules of C4H10 react ... of aluminum and 73.15 g of sulfur are combined to form aluminum sulfide according to the equation:.
Explanation:
A plastic rod that have just been rubbed with a fur and kept near a negatively charged ballon that is freely suspended. The charged balloon moves away from the plastic. What does this explain you ?
Explanation:
that both the plastic & balloon have the same charge
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7. In science, the process/thing that you examine/focus on is called the ??
and anything outside of this focus is called the ??
Answer:
Subject of the experiment and out of scope
Explanation:
In any research study, the process of thing studied is basically the subject of the experiment on which research is conducted to determine the outcomes. If any thing lies out of the experimental process reach, then it is said to be out of scope of the experiment.
The idea that light can act like packets led to what new field on science?
Light acting as 'packets' of exact amounts of energy (a particle-like quality) called quanta led to the development of quantum mechanics. Light also has wave qualities (wavelength, frequency, amplitude) which is referred to as particle-wave duality.
Why do vinyl raincoats become brittle as they get old, even if they are not exposed to air or to any pollutants
Answer:
The substances made from polyvinyls are generally brittle and hard. This property prevails because the polymer strands present in the polyvinyls form a very regular and well-organized packing composition in the solid-state. The Van der Waals associations between the strands make the substance brittle. To make the substance soft and suitable to use as a raincoat, the incorporation of small molecules is done within the molten polymer before the hardening of the plastic.
These polymer strands act as plasticizers and prevent the strands of polymer from forming a hard and brittle conformation.
Correct order of the levels of classification in the ecosystem
What is the colour change when universal indicator is added to a solution containing potassium
in water?
Answer:. Dark purple
(b). Orange yellow
(c). Red
Explanation:
5.
When 0.421 g of BaCl2:2H20 and 0.722g of Na3PO4.12H2O mix with water
forming 500 mL of solution, how many grams of Ba3(PO4)2 precipitate?
Explanation:
2H2O and 0.722g of Na3PO4.12H20 mix with water forming 500 mL of solution, how many grams of Ba3(. ... Forming 500 ML Of Solution, How Many Grams Of Ba3(PO4)2 Precipitate?
When 0.421 g of BaCl₂ · 2 H2O and 0.722g of Na₃PO₄ · 12 H₂O mix with water forming 500 mL of solution then 0.003 mol/L of Ba₃(PO4)₂ precipitate.
What is Stoichiometry ?Stoichiometry is an important concept which helps us use the balanced chemical equation to measures the amount of reactants and products.
What is Molarity ?Molarity of solution is the number of moles of solute per liter of solution. Molarity is also called Molar Concentration.
Molarity (M) = [tex]\frac{\text{number of moles}}{\text{volume of solution (in liters)}}[/tex]
How to find the number of moles ?Number of moles = [tex]\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
First we have to write the balanced chemical equation
2Na₃PO₄ · 12 H₂O + 3BaCl₂ · 2 H2O → Ba₃(PO4)₂ + 6 NaCl + 30 H₂O
Here 3 moles of BaCl₂ · 2 H2O produce 1 mole of Ba₃(PO4)₂
So,
Number of moles of BaCl₂ · 2 H2O = [tex]\frac{\text{Mass of}\ BaCl_2 . 2H_2O}{\text{Molar mass of}\ BaCl_2. 2H_2O}[/tex]
= [tex]\frac{0.421}{244.26}[/tex]
= 0.017
Number of moles of 2Na₃PO₄ · 12 H₂O = [tex]\frac{\text{Mass of}\ Na_3PO_4. 12H_2O}{\text{Molar mass of}\ Na_3PO_4 . 12H_2O}[/tex]
= [tex]\frac{0.722}{380.12}[/tex]
= 0.002
Therefore, Na₃PO₄ · 12 H₂O is the limiting reagent.
Now, put the value in above formula to find the molarity
Molarity (M) = [tex]\frac{\text{number of moles}}{\text{volume of solution (in liters)}}[/tex]
= [tex]\frac{0.0017}{0.5}[/tex]
= 0.003 mol/L
Thus, from above conclusion we can say that 0.003 mol/L of Ba₃(PO4)₂ precipitate.
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Boron has five protons and six neutrons. What is the atomic mass of boron?
A. 11
B. 10
C. 12
D. 1
Answer:
11
Explanation:
becauase 5 +6