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.
To know more about Half life,
What pressure, in atm, is required to reduce 60.0 mL of a gas at standard conditions to
10.0 mL at a temperature of 25.0 °C?
What is the IUPAC name
HCl(acid)+C₄H₈ (butene)⇒ addition reaction
name of the product: 2-cloro butane
Scientists hypothesize that Earth's first oceans were made of fresh water. How did oceans obtain fresh water?
*
1 point
Water vapor in the early atmosphere cooled and fell to Earth as rain.
Frozen comets that fell to Earth melted as they traveled through the atmosphere.
As soon as icecaps formed, they melted because Earth was still very hot.
Early terrestrial organisms exhaled water vapor, which condensed to form fresh water.
The earth's first oceans would have obtained freshwater as a result of the condensation of water vapor in the atmosphere back then.
How were oceans formed?The freshwater of oceans was hypothesized to have been formed by the condensation of water vapor present in the early atmosphere of the earth.
The water vapor was thought to have emanated from volcanic activities. The condensation was in the form of rain and the resulting puddles merged together to form the oceans.
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in a given homologous series of hydrocarbons, the boiling point generally increases as the size of the molecules increases. the best explanation for this statement is that in larger organic molecules
The boiling point of hydrocarbons generally increases as the size of the molecules increases because more bonds are needs to be broken in larger organic molecules.
What are hydrocarbons?Hydrocarbons are organic compounds which here composed of hydrogen and carbon alone.
Hydrocarbons are grouped into families or homologous series based on a reactive group known as the gincyiial group
The homologous series include
alkanesalkenes alkynesThe boiling point generally increases as the size of the molecules increases because more bonds are needs to be broken in larger organic molecules.
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HELP QUICKLY PLEASEEE
Answer:
Ionic bonds are when electrons are gained/lost. Hence the valence charges.
Which organisms are producers?
Choose all correct answers.
tree
grass
monkey
mold
Answer: Tree and Grass are the two correct answers here
Explanation: Producers are photosynthesizing organisms. They are any kind of green plant that make their food by taking sunlight and using the energy to make sugar.
Answer:
Tree, grass
Explanation:
Producers make their own food. Trees and grass can make their own food using sunlight (photosynthesis). Monkey is consumer (eats other things like bananas- made by plants - for survival). Mold (like fungus) eat dead stuff and thus are decomposers (not producers).
You and your classmates are working to develop a prototype for a new type of drone. The drone needs to fly and will be controlled by a remote control. Which STEM fields would be most important for you to have knowledge of to build this drone?
A) chemistry and botany
B) astronomy and geology
C) medicine and geology
D) physics and computer science
What is a network solid?
a
A. A crystalline solid held together by intermolecular forces
B. A crystalline solid held together by charge attractions
C. A crystalline solid held together by metallic bonds
O D. A crystalline solid held together by covalent bonds
SUBMIT
Network solids are chemical compounds that are bound together by a covalent bond. Thus, option D is accurate.
What are covalent bonds?Covalent bonds are the type of chemical bonds that mutually shares electrons between the atoms of the molecules of the compound.
A covalent crystal of network solids is held together by the covalent bond that can be seen in the structures of diamonds, graphite, silicon dioxide, etc.
Therefore, the network solids are option D. held by the covalent bonds.
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How does the Pauli exclusion principle affect orbital filling? Give an example of a 2p orbital diagram for which Paul Exclusion principle is violated.
Pauli's exclusion principle states that no two subshells of same element have same 4 quantum numbers.
Take example of Berrilim orbital
Electronic configuration is given by 1s²2s²
But the orbital is
[tex]\\ \rm\Rrightarrow \huge{\boxed{\uparrow\downarrow}}\:\:\huge{\boxed{\uparrow\downarrow\mid\:\:\:\:\mid\:\:\:}}[/tex]
fossil fuel in a sentence
biomass in a snentence
Answer:
Below•
Explanation:
Fossil Fuel: It's a natural gas based on natural materials such as coal.
Biomass: It's the total weight of substance.
[tex] \qquad \qquad...[/tex]
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
ammonia and hydrogen fluoride both have unusually high boiling points due to
Answer:
hydrogen bonding, hope this helps
Explanation:
Use the information in the tables to determine whether the solution of the salt formed from the given acid base combinations will be acidic, basic, or neutral. hcl naoh: hcl nh4oh: ch3cooh koh:
The table should be included, but that's okay
hcl naoh: salt neutral (both strong)
hcl nh4oh: salt acidic(strong acid+weak base)
ch3cooh koh: salt basic(weak acid+strong base)
I need this now for a test
explain why the dust clouds that moved to the east coast of the united states during the 1934 storm were composed mostly of silt and clay particles
instead of sand
Dust clouds that moved to the east coast of the united states were composed mostly of silt and clay particles due to constant ploughing during drought.
What is Drought?This is defined as dry period in the climate due to insufficient rainfall in the area at a given time.
The drought led to the soil being constantly ploughed thereby loosening and changing the soil type which is susceptible to wind erosion.
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The fact that water is attracted to itself, a property called:.
12 Describe In your own words, describe the glassblowing process.
Explanation:
To give the glass its final shape and size, it is blown into with a blowpipe, creating a sort of bubble of glass. To carry out this process, the blowpipe holding the glass must be placed on a steel stand. Then, the glass artist has to blow into the blowpipe while rotating it at the same
Use the word bank below to complete the statement. Not all of the words will be used.
Word Bank:
sum. Enthalpy. Heat. Total.
Temperature. Moles. -ΔH. +ΔH.
Hess’s Law describes how the ____ energy of a reaction consists of the ___ of the energy changes of the individual step reactions.
Answer:
Hess’s Law describes how the __Heat__ energy of a reaction consists of the _Enthalpy__ of the energy changes of the individual step reactions
Explanation:
Hess law is a legendary law which is given by
[tex]\\ \rm\Rrightarrow ∆H_{net}=\sum \delta H_r[/tex]
Which of the following is Not a physical change?
A. Grating cheese
B. Melting cheese
C. Fermenting cheese
D. Mixing two cheeses in a bowl
Answer:
c: fermenting of cheese
Answer:
c
Explanation:
2. What is evolution?
Explanation:
Evolution is a biological process. It is how living things change over time and how new species develop.
Answer: It’s B
Explanation:
The radioisotope that has the longest half-life is the best to use in powering planet and space exploration vehicles because they can travel farther. which radioisotope is the best to use? lithium-5 uranium-240 carbon-14 plutonium-239
The best radioisotope to use in powering planet and space exploration is plutonium-239 since it has the longest half-life of 21400 years.
What is Half-Life of radioactive element?The half-life ofa radioactive element is the time it takes for half the amount of atoms in the element to spontaneously decay.
The half-life of radioactive elements vary.
The half life of the given radioactive elements are as follows:
lithium-5 is 3.038×10^-22 secondsuranium-240 is 14.1 hours carbon-14 is 5700 years plutonium-239 is 21400 yearsTherefore, the best radioisotope to use in powering planet and space exploration is plutonium-239 since it has the longest half-life of 21400 years.
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Answer:
D. ) Plutonium-239
What is the "modern" definition of atomic theory?
Answer: The modern atomic theory states that atoms of one element are the same, while atoms of different elements are different. Each element has its own characteristic atomic number. Atoms of the same element can have different numbers of neutrons, however.
Explanation: N/A
A student mixed two chemicals to allow them to
react. The temperature before the reaction was 25
°C. The temperature after the reaction was 50° C.
Which of the following is true?
A. there was no change in heat energy
B. it is an exothermic reaction
help plsssss
Answer:
B .it is an exothermic reaction
Explanation:
i need brainleyest
Evaluate which factor is most likely to cause the concentration of greenhouse gases in the earth's atmosphere to increase?
A.
decreased number of decomposing plants
B.
decreased number of volcanic eruptions
C.
increased frequency of earthquakes
D.
increased human industrial activities
Answer:
D. increased human industrial activities
Using the rxn below determine the following: What is the limiting reagent, theoretical yield of nitic oxide, and how many grams of excess reagent remain when producing nitric oxide when using 4.65g of ammonia to react with 4.25g of oxygen?
5 mols of O_2 need 4 mol NH_3
As mols of ammonia are less Ammonia is limiting reagentNow
Moles of Ammonia
Given mass/Molar mass4.65/170.3molMoles of NO=0.3mol
Mass of NO
0.3(30)9gSo
Moles of Oxygen
4.25/320.13molRemaining moles
0.3-0.13=0.17Mass
0.17(32)5.44gYield
5.44-4.250.79gName these compounds according to IUPAC.
Functional groups are the specific groups that provide characteristic properties. The compounds are butanoic acid and methyl propanoate.
What are functional groups?Functional groups are the active side atoms and molecules that confer the physical and chemical properties of the compound. In the first compound, the functional group is the carboxylic acid (COOH) and four carbon atoms hence, the compound is butanoic acid.
In the second compound, the functional group is an ester (RCOOR) and contains a methyl group and other three carbon atoms making the compound, methyl propanoate.
Therefore, the compounds are butanoic acid and methyl propanoate.
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The radioactive decay of Uranium-238 releases alphas particles and results in a mass change of 0.135 g. Determine the amount of energy released by this reaction
a) 1.22 x 10^13J
b) 1.22 x 10^16J
c) 4.05 x 10^4J
d) 4.05 x 10^7J
This question involves the concept of binding energy.
The amount of energy released by this reaction is "a) 1.22 x 10¹³ m/s".
What amount of energy is released?The amount of energy that is released during the radioactive decay of any element is known as binding energy. This can be given by using the following formula:
[tex]E=\Delta mc^2[/tex]
where,
E = energy released = ?Δm = mass change = 0.135 g = 1.35 x 10⁻⁴ kgc = speed of light = 3 x 10⁸ m/sTherefore,
E = (1.35 x 10⁻⁴ kg)(3 x 10⁸ m/s)²
E = 1.22 x 10¹³ m/s
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distance in space is measured in
24. Explain why a saturated solution is not necessarily a concentrated solution.
Answer:
A saturated solution may not be a concentrated solution IF the solute is only sparingly or slightly soluble in the solution.
a.
Convert these temperatures to Kelvin:
A. -22 °C
b. 206 °C
C. 50 °C
d. 8 °C
Like this
-22°C + 273.15 = 251.15K
206°C + 273.15 = 479.15K
50°C + 273.15 = 323.15K
8°C + 273.15 = 281.15K
The conjugate base of a strong acid will always . . .
be acidic
be basic
be a spectator
