Answer:
15.625 g of a 500 gram sample of potassium-42 with 12.4 hours of Half -life is left after 62 hours.
The half-life is the time after which half of the initial quantity of a radioactive substance is left .
Given here,
The half-life of K-42 = 12.4 hours
The initial quantity of K-42 = 500 gm
The final quantity after 62 hours = ?
The number of half cycle
Thus the number of half life cycles in 62 hours is 5,
After 1 half life
After 2 half lives
After 3 half lives
After 4 half lives
After 5 half lives
15.625 g of a 500 gram sample of potassium-42 with 12.4 hours of Half -life is left after 62 hours.
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WILL GIVE BRAINLIEST What would the products of a double-replacement reaction between LiCl and MgO be? (Remember: In double-replacement reactions, the two cations switch places and the two anions switch places.)
If brainly deletes one more of my answers when im just answering the question correctly im suing bro
Answer:
The moderators are just there to delete relevant questions or answers but they aren't deleting the spammers .
Explanation:
Stay safe, stay healthy and blessed.
Have a good day !
Thank you
14
Select the correct answer.
The perihelion is the point at which Earth is closest to the Sun, and the aphelion is the point at which Earth is farthest away. Based on this
information, which statement is true?
O A. Earth moves faster along its orbit during perihelion because of the Sun's gravitational force.
O B. Perihelion marks the beginning of summer, when Earth is closest to the Sun.
• C
The longest day of the year occurs during perihelion due to a lunar eclipse.
© D. The Moon rotates faster during perihelion because of Earth's gravitational force.
Answer: B
Explanation: I know
Which of the following is the best hypothesis?
OA. Physical changes are much less interesting to watch than
chemical changes.
B. If sodium carbonate is added to vinegar, the reaction will absorb
heat.
C. Tearing a piece of paper is an example of a physical change.
D. Some chemical reactions absorb heat, and others release heat.
SUBMIT
Help me y’all
Answer:
B.) If sodium carbonate is added to vinegar, the reaction will absorb heat.
Explanation:
A.) is incorrect because this is not testable. Rather, it is just an opinion that cannot be proven correct or incorrect.
B.) is correct because this statement is testable. Tests need to be run to determine the accuracy of the statement.
C.) is incorrect because this statement explains something that does not need to be tested. It is an example of a physical change when one tears a piece of paper.
D.) is incorrect because this is already a true statement. It is obvious that not all reactions absorb/release heat. While tests could be run to further prove this statement true, it is already considered accurate.
How many grams of sodium chlorate(nacio3) are in 1.23 x10^23 representative particles?
Answer:
About 21.7 grams.
Explanation:
To find the mass of a sample of sodium chlorate (NaClO₃) given the amount of particles present, we can convert from particles to moles, and moles to mass using its molecular weight.
The molecular weight of sodium chlorate is:
[tex]\displaystyle \begin{aligned} \mathcal{M}_\text{NaClO$_3$} &= (22.99 + 35.45 + 3(16.00)) \text{ g/mol} \\ \\ & = 106.44\text{ g/mol} \end{aligned}[/tex]
And recall that in one mole of any substance, there are 6.02 × 10²³ of it. Hence:
[tex]\displaystyle \begin{aligned} 1.23\times 10^{23} \text{ NaClO$_3$} &\cdot \frac{1\text{ mol NaClO$_3$}}{6.02\times 10^{23}\text{ NaClO$_3$}} \cdot \frac{106.44\text{ g NaClO$_3$}}{1\text{ mol NaClO$_3$}} \\ \\ &= 21.7 \text{ g NaClO$_3$} \end{aligned}[/tex]
In conclusion, there are about 21.7 grams of sodium chlorate.
This atom can form up to _____ single covalent bond(s). An atom with two electron shells. There is one electron pair in the inner electron shell and four unpaired electrons in the outer electron shell. 0 1 4 2 3
Answer:
4
Explanation: it's a carbon atom right....soo it'll form 4 bonds(single)
An atom can form 4 single covalent bonds is carbon with two electron shell.
What are covalent bonds?The bonds are defined as a strong bond that binds atoms, ions, or molecules together and promotes the production of molecules.
There are three types of bonds.
Ionic bondCovalent bondMetallic bondCovalent bonds are defined as the bond formed by sharing of electrons with each other.
Covalent bonding is a stable equilibrium of the attractive and repulsive forces between two atoms that occurs when they share electrons. Bonding pairs or sharing pairs are other names for these electron pairs.
It can also be defined as a type of chemical link where atoms share electrons to create electron pairs.
Covalent bonds has low melting point, boiling point, enthalpy of fusion and enthalpy of vaporization.
Thus, an atom can form 4 single covalent bonds is carbon with two electron shell.
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The equilibrium concentrations for the reaction between N2 and O2 to form NO at a certain temperature are given in the table below. What is the equilibrium constant for the reaction?
A. 42
B. 2.4 x 10^-2
C. 4.2 x 10^-4
D. 21
Answer:
c
Explanation:
c is correct i believe
2 NH3 + 3 CuO → 3 Cu + N2 + 3 H2O
In the above equation, how many grams of N2 can be made when 12.2 moles of CuO are consumed?
Answer:
114 grams N₂
Explanation:
To find the answer, you need to (1) convert from moles CuO to moles N₂ (via the mole-to-mole ratio from equation) and then (2) convert from moles to grams (via molar mass from the periodic table). The final answer should have 3 sig figs according to the given value (12.2).
2 NH₃ + 3 CuO --> 3 Cu + 1 N₂ + 3 H₂O
Molar Mass (N₂): 2(14.01 g/mol)
Molar Mass (N₂): 28.02 g/mol
12.2 moles CuO 1 mole N₂ 28.02 grams
----------------------- x ----------------------- x ----------------------- = 114 grams N₂
3 moles CuO 1 mole N₂
Select the correct answer from each drop-down menu. 2naoh h2so4 → na2so4 h2o the equation is because the number of hydrogen atoms and atoms is in the reactants and in the products.
The equation will balance because the number of hydrogen atoms and atoms is in the reactants and in the products in this case is 2.
How to balance reactions?
Reaction balancing is a method used in several areas of Chemistry to determine the amount of matter of each of the substances participating in the reaction, as well as to establish the existing proportions between the components.
So, since you must have the same amount of sodium and chlorine on each side of the reaction, then you have multiplay the NaCl for 2.
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WILL GIVE BRAINLIEST! Please help me because I am unable to find help and I have to turn in this assignment or else I will fail this class for the year. I AM NOT ACCEPTING FILES!!
The statement about the number of moles of acid and base being the same is true in the neutralisation reaction between the acid HCl and base NaOH.
What is neutralisation reaction?A neutralisation reaction is the type of chemical reaction whereby an acid reacts with a base to form salt and water.
HCl + NaOH --------> NaCl + H2O
In the neutralisation reaction, between the acid HCl and base NaOH above, the balanced chemical equation showed that the initial number of moles of acid is equal to the final amount of the number of moles of known base which is NaOH.
Therefore, the statement about the number of moles of acid and base being the same is possible in the neutralisation reaction between the acid HCl and base NaOH.
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Just look at pic please it has the question and answers
[tex]\qquad\qquad\huge\underline{{\sf Answer}}[/tex]
Let's balance the given equation ~
[tex]\qquad \sf \dashrightarrow \:S_8 + O_2 \rightarrow SO_3[/tex]
[tex] \textsf{Step 1 - balance Sulphur (S) on both sides} [/tex]
[tex] \textsf{[ By multiplying} [/tex] [tex] \sf{SO_3} [/tex] [tex] \textsf{by 8 on product side ]} [/tex]
[tex]\qquad \sf \dashrightarrow \:S_8 + O_2 \rightarrow 8 \: SO_3[/tex]
[tex] \textsf{Step 2 - balance Oxygen (O) on both sides} [/tex]
[tex] \textsf{[ By multiplying} [/tex] [tex] \sf{O_2} [/tex] [tex] \textsf{by 12 on reactant side ]} [/tex]
[tex]\qquad \sf \dashrightarrow \:S_8 +12 \: O_2 \rightarrow 8 \: SO_3[/tex]
So, we can infer that the Correct choice is D
Some calcifiers can use bicarbonate (HCO3-) to make their shells.
How will they be affected by the decrease in pH?
Answer:
The removal of this ion from water by the calcifiers will definitely decrease the pH of water.
What is the bicarbonate ion?
The bicarbonate ion is the ion that is designated as HCO3-. We must notice that this ion is present in abundant amounts in the sea. This amount definitely make the sea slightly alkaline.
Now we must note that the removal of this ion from water by the calcifiers that require it to make their shell will definitely decrease the pH of water.
Explanation:
The removal of this ion from water by the calcifiers will definitely decrease the pH of water.
What is the bicarbonate ion?The bicarbonate ion is the ion that is designated as [tex]HCO^{3-}.[/tex] We must notice that this ion is present in abundant amounts in the sea. This amount definitely makes the sea slightly alkaline.
Now we must note that the removal of this ion from water by the calcifiers that require it to make their shell will definitely decrease the pH of water.
Hence, the removal of this ion from water by the calcifiers will definitely decrease the pH of water.
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all waves, except electromagnetic waves, need a medium to travel through. what is a "medium"? give 2 examples
Answer:
air water
Explanation:
Mediums that can have waves
1. Why does cabbage juice have different colors at different pH levels?
2. Would the solution be acidic or basic when cabbage juice is pink?
1:Red cabbage contains a water-soluble pigment called anthocyanin that changes color when it is mixed with an acid or a base.
2: Basic
Jack would probably say his lines with a _______ voice.
A. puzzled
B. delighted
C. whining
A. because he might be in trouble in a play
Please help I do not understand
A model of materials will show dense materials having tightly packed particles while less dense materials will have greater spaces between their particles.
What is density?Density is a measure of the compactness of a material.
Density is defined as the ratio of mass to the volume of a substance.
Density = mass/volumeDense materials have tightly packed particles while less dense materials have greater spaces between their particles.
Avogadro's hypothesis applies to substances in gaseous form since they do not have a constant volume.
Therefore, a model of materials will show dense materials having tightly packed particles while less dense materials will have greater spaces between their particles.
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Name these compounds according to IUPAC.
IUPAC is the nomenclature approach used for naming compounds. The compounds are ethane, butane, and butene.
What is IUPAC?IUPAC is the nomenclature method of the organic compounds that are universal and is recommended by the International union so that the names of the same chemical species are constant and ubiquitous all over.
The first compound has a single bond and two carbons hence ethane, the second compound has a single bond and four carbons and hence butane, and the third compound has one double bond and four carbon atoms and hence butene.
Therefore, the compounds are ethane, butane, and butene.
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Which of the following increases air’s ability to hold water vapor? a. increase in wind speed c. decrease in temperature b. increase in temperature d. decrease in air pressure Please select the best answer from the choices provided A B C D
Increase in temperature increases air's ability to hold water vapour. That is option B.
What is water vapour?Water vapor is defined as the form of water when in gaseous state.
Water turns to vapour when heat is added to it leading to evaporation.
Therefore, Increase in temperature increases air's ability to hold water vapour.
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The electrons between atoms in metallic bonds
allow for bonding metals to be reactive.
allow for bonding metals to be stable.
are stationary and provide durability to the metal.
are attracted to the neutrons of the metal.
Answer:
Metallic bonding is the type of chemical bonding that occurs between atoms of metals. In a metallic bond, atoms share their electrons in a way that allows them to form a “sea” of free electrons. This electron sea is responsible for the unique physical and electrical properties of metals.
Explanation:
Answer:
B. allow for bonding metals to be stable.
Explanation:
edge 2022
Name the molecule in the picture
Answer:
1,3 - dimenthylbenzene
Right option is (c).
Explanation:
⠀
⠀
As here in the figure, we can see the hexagonal shape with a circle inside it which depicts the benzene ring. And at 1 and 3 carbon atom, the methyl group is attach to the it.
⠀
It's formula will be
[tex] \sf C_8H_{10}[/tex]
It is also known as m-xylene.
⠀
And this organic compound is used in leather and rubber industries.
If you have 294grams of a decaying isotope, how many grams will remain active after 4 half-lifes?
Answer:
18.375 gm left
Explanation:
1/2 ^4 = 1/16th will be left (see the '4' representing 4 half lives?)
294 * 1/16 = 18.375 gm
What does the number at the end of an element mean? (For example, Hydrogen-3)
Answer:
The top number is the total mass number, particles in an atom of an element that have mass are protons and neutrons.
Explanation:
How many molecules are in a 45g sample of water?
Answer:
Solution : Number of moles of water `=(" Mass of water ")/(" Gram molecular mass of water ")= (45g)/(18g)= 2.5`. Step by step solution by experts to help you in doubt clearance & scoring excellent marks in exams.Explanation:
Hope It helps uHow is knowing conduction of heat useful to us? Explain in your own words please xx
There are a lot you want to know about heat transfer.
If u understand the mode of heat transfer well, then heat transfer is easy to continue.
Answer:
1: They give to the body Vitamin D 2: they give solar energy and that is what gives us revaluation around the sun (Drag) 3: it gives plants energy for photosynthesis (or dont know)
4:solar panels gives energy by the sun radio controlled area that gives us the battery's, lights etc...
Explanation:
EXPLAIN IT
The common functions of all cells include:
5. Elements are different because they contain different numbers of protons.
Answer:
True
Explanation:
The number of electrons are what determine an atom.
The number of electrons = number of protons
so the elements are different.
If the number of neutrons are different but the number of electrons and protons are same they are of the same element.
But here the number of protons are different so this is another element.
2.0 mL of a 0.75 M solution of potassium permanganate , KMnO4 solution is used to make a 500 mL solution . What is the concentration of the new solution ?
The concentration of the new solution is 0.003 M.
How do we calculate the required concentration?Required concentration of the final solution will be calculated by using the below equation as:
M₁V₁ = M₂V₂, where
M₁ & V₁ are the molarity and volume of initial solution.
M₂ & V₂ are the molarity and volume of final solution.
On putting values from the question, we get
M₂ = (0.75)(2) / (500) = 0.003 M
Hence required concentration is 0.003M.
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how do atoms show both unity and diversity
Answer: As one atomic dipole nears another atom it will affect the electron density distribution, so for example if the slightly positive end of the atom is located next to another atom, it will attract the electron(s) in the other atom. A covalent bond happens when atoms share an electron between them. The other kind of bond is called ionic, and it happens when one atom gives an electron to another atom. These bonds are held together with electric forces. Two atoms of the same element can be different if their electrons are in different states. If one copper atom has an electron in an excited state and another copper atom has all of its electrons in the ground state, then the two atoms are different.
Answer:
there are relatively few atoms but they can make many molecules
Explanation:
If a substance cannot be separated by physical means or chemical means, it is ___________.
Question 4 options:
an element
a solution
a molecule
a compound
An element is a pure substance that cannot be separated into simpler substances by chemical or physical means
Answer:
It is an element.
Explanation:
chemical element, also called element, any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed.
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35.0g of zinc oxide react with what volume of oxygen at stp given the following reaction: zn + o2 --> zno
The volume of oxygen that would react at STP will be 6.00 L
Stoichiometric calculationFrom the equation of the reaction:
[tex]2Zn + O_2 --- > 2ZnO[/tex]
The mole ratio of [tex]O_2[/tex] to the ZnO produced is 1:2
Mole of 35 g Zn = 35/65.3 = 0.536 moles
Equivalent mole of [tex]O_2[/tex] that will react = 0.536/2 = 0.268 moles
1 mole of gas at STP = 22.4 L
0.268 moles of gas = 0.268 x 22.4 = 6.00 L
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