Answer!
After 2 years, 1.986 g of a radioisotope material remains from a sample of the original mass of 2g, what is the half-life of the sample? - Radioactive decay occurs according to the formula:
A = A0 * exp(-ln(2) * t/T1/2)
The Original activity or mass A0 will decay to be A after time t where T1/2 is the decay time or half-life. If you fill in the values for A, A0 and t (= 2 years) you will end up with a value of approximately 188 years for the half-life.
Which term is defined as long chains of carbon molecules?.
Answer: polymers
Explanation:
Polymers are huge natural molecules are connected with small natural molecules
50.0 g of nitrogen gas (N2 ) are kept under pressure in a 3.00 L container. If the pressure is kept constant, how many moles of nitrogen gas are present in the container if gas is added until the volume has increased to 5.00 L?
The resultant moles of nitrogen gas that are present in the container is 2.96 moles.
How do we convert mass into moles?Mass of any substance will be converted into moles by using the below equation as:
n = W/M, where
W = given mass of nitrogen gas = 50gM = molar mass of nitrogen gas = 28 g/mol n = 50 / 28 = 1.78 molesFrom the ideal gas equation of gas we know that moles and volume is directly proportional to each other and for this question equation becomes,
V₁/n₁ = V₂/n₂, where
V₁ & n₁ are the initial volume and moles of gasV₂ & n₂ are the final volume and moles of gas.On putting all values, we get
n₂ = (5L)(1.78mol) / (3L) = 2.96 moles
Hence required moles of nitrogen gas are 2.96.
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Question 5 of 5
A spiral staircase like the one shown can be a model of the
structure of a DNA molecule.
In this model, what do the steps on the staircase represent?
Answer:
A
Explanation:
l took the test
PLEASE HELP ASAP!!!!!
Which statements explain why rocks weather at different rates? Check all that apply.
Softer, porous, or more permeable rocks weather faster than harder rocks.
Rocks in warmer climates weather faster than rocks in colder climates.
Rocks with minerals that dissolve slowly in water will weather faster than other rocks.
The more water present, the faster the rate of weathering.
Rocks that are more permeable are more resistant to weathering.
The correct statements which explain why rocks weather at different rates are: A. Softer, porous, or more permeable rocks weather faster than harder rocks. B. Rocks in warmer climates weather faster than rocks in colder climates. and D. The more water present, the faster the rate of weathering. Hence , Option A , B and D are correct
What is Weathering of rocks ?Weathering can be defined as both the physical and chemical breakdown of a rock into smaller fragments (pieces) called sediment.
Generally, rocks weather at different rates based on the following reasons:
Rocks that are softer, porous, or more permeable in nature, weather faster than harder rocks.Rocks that are located in warmer climates weather faster than those rocks located in colder climates.Weathering is highly dependent on water: the more water present in a rock, the faster the rate of its weathering.Some of the natural phenomenon that influences rock cycle include the following;
Plate tectonic activity.Erosion.Weathering.Therefore , The correct statements which explain why rocks weather at different rates are: A. Softer, porous, or more permeable rocks weather faster than harder rocks. B. Rocks in warmer climates weather faster than rocks in colder climates. and D. The more water present, the faster the rate of weathering. Hence , Option A , B and D are correct
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Answer: A., B., D.
Explanation:
What is the molar solubility of aucl3 (ksp = 3. 2 x 10-23) in a 0. 013 m solution of magnesium chloride (a soluble salt)?
The molar solubility of AuCl₃ in a 0.013 M solution of magnesium chloride is 1.81×10⁻²⁸M.
What is Ksp?The solubility product constant, Ksp, is the equilibrium constant for a solid substance dissolving in an aqueous solution. And for the AuCl₃, Ksp will be written as: Ksp = [Au³⁺][Cl⁻]³
Let the solubility of the AuCl₃ in 0.013M solution of magnesium chloride is x, of Au³⁺ is x and of Cl⁻ is 3x. But we know that MgCl₂ is a strong electrolyte and it completely dissociates into its ions and will produce 2 moles of chloride ions. For this solution let we consider the volume is 1 liter then the concentration of chloride ions in MgCl₂ is 2(0.013)=0.026M.
So, in MgCl₂ solution concentration of Cl⁻ becomes = 3x + 0.026.
Value of Ksp for AuCl₃ = 3.2 × 10⁻²³
On putting all values on the Ksp equation, we get
Ksp = (x)(3x + 0.026)³
Value of 3x is negligible as compared to the 0.026, so the equation becomes
3.2 × 10⁻²³ = (x)(0.026)³
x = 3.2×10⁻²³ / (0.026)³
x = 1.81×10⁻²⁸M
Hence the molar solubility of AuCl₃ in 0.010M MgCl₂ is 1.81×10⁻²⁸M.
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please help i have finals coming up!!
Answer:
.475 M
Explanation:
USe periodic table to find mole weight of HCl
H = 1.008 Cl = 35.45 total 36.458 gm / mole
Find the numebr of moles in 52 gm
52 gm / ( 36.458 gm / mole) = 1.426 moles
1.426 moles / 3 L = .475 M
4. how are ions related to the magnetic field of the earth?
Answer:
When ions move over a polar cap of Earth, the changing shape of the magnetic field lines bends the drift path induced by the electric field normal to the magnetic field. The centrifugal acceleration associated with this bending shoots the ions away from the Earth along the magnetic field lines
Explanation:
Using this Punnett Square, what percentage of offspring can display the recessive trait?
100%
50%
25%
0% No offspring can display the recessive trait
Answer: 0% No offspring can display the recessive trait
just did the test
What is the correct order of the atmospheric layers from bottom to top
The correct order of the atmospheric layers from bottom to top are
The lowest layer that is the TroposphereThe layer right above the troposphere is the StratosphereThe layer above the Stratosphere is the MesosphereThe layer above the Mesosphere is the ThermosphereThe topmost layer that continues till it merges with space is the ExosphereLas Vegas is a city in the middle of the Mojave Desert. In 1933, the Hoover Dam was built creating Lake Mead, a large water reservoir to the east of Las Vegas. Select all the options that were the primary reason for creating this reservoir.
options:
People needed a place for recreational use of the lake for swimming and boating.
Population was continuing to grow since settlement in the Las Vegas area.
The natural springs were in danger of drying up due to over pumping of the aquifer beneath Las Vegas.
To increase city revenue by encouraging people to come see Hoover Dam, the largest dam in the United States.
Answer:
Natural Springs answer.
Explanation:
Actually valid reason for why the dam was built
The bronsted-lowry model can apply to bases that do not contain hydroxide ions
The statement that bronsted - lowry model can apply to bases that do not contain hydroxide ions is true.
What is Bronsted - lowry model?
The Bronsted - Lowry theory, also known as the proton theory of acids and bases, is a theory developed independently by chemist Johannes Nicolaus Bronsted and English chemist Thomas Lowry in 1923.
The theory states that as acid is a substance that can donate electrons and bases are those which can accept electrons.
Thus, the statement that bronsted - lowry model can apply to bases that do not contain hydroxide ions is true.
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DRAW THE STRUCTURE (ASAPP)
The structure of 3-ethyl-2 fluroheptane is attached. The chemical formula of the compound is C9H19F.
What is 3-ethyl-2 fluroheptane?It is an organic compound which has one pair of hydrogen and acceptor and zero hydrogen bond donor.
The chemical formula of the compound is [tex]C_9H_1_9_F.[/tex]
Thus, the structure of 3-ethyl-2 fluroheptane is attached. The chemical formula of the compound is C9H19F.
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An element in Group 2 of the periodic table likely has which characteristics?
shiny solid, conducts heat and electricity, easily bends
shiny solid, does not conduct heat but does conduct electricity, crumbles easily
dull solid, does not conduct heat or electricity, does not bond with other atoms
gas, does not conduct heat or electricity, easily bonds with other atoms
Answer:
Option #1: shiny solid, conducts heat and electricity, easily bends
Explanation:
alkaline-earth metal, any of the six chemical elements that comprise Group 2 (IIa) of the periodic table. The elements are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
These physical properties of group 2 elements are: low density (mass over volume) low melting points (except beryllium) low boiling points (except beryllium)
♡ The Question/Task(s)! ♡
✦ || An element in Group 2 of the periodic table likely has which characteristics?
︶꒦︶꒷︶︶ʚ♡ɞ︶︶꒷︶꒦︶
♡ The Answer(s)! ♡
✦ || The answer is, "Shiny solid, conducts heat and electricity, easily bends"!
I apologize in advance if the answer is incorrect! ♡
︶꒦︶꒷︶︶ʚ♡ɞ︶︶꒷︶꒦︶
♡ The Explanation(s)/Step-By-Step! ♡
✦ || The elements in Group 2 of the periodic table consist of malleable metals! The elements have a soft metallic texture that can be shaped, and can conduct a source of both electricity and heat!
︶꒦︶꒷︶︶ʚ♡ɞ︶︶꒷︶꒦︶
♡ Tip(s)! ♡
✦ || No Tips Provided!ヽ(>∀<☆)ノ
3. 0.050 mol of Ca(OH)2 are combined with 0.080 mol of HCl according to the following equation:
Ca(OH)2(aq) + 2HCl(aq) +CaCl2(aq) + 2H2O(1)
a. How many moles of HCl are required to neutralize all 0.050 mol
of Ca(OH)2?
The number of mole of HCl required to neutralize all 0.05 mole of Ca(OH)₂ is 0.1 mole
Balanced equationCa(OH)₂ + 2HCl —> CaCl₂ + 2H₂O
From the balanced equation above,
1 mole of Ca(OH)₂ required 2 moles of HCl
How to determine the mole of HCl requiredFrom the balanced equation above,
1 mole of Ca(OH)₂ required 2 moles of HCl
Therefore,
0.05 mole of Ca(OH)₂ will require = 0.05 × 2 = 0.1 mole of HCl
Thus, 0.1 mole of HCl is needed for the reaction
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4.8 L sample of helium gas contains 0.22 moles of helium - How many additional moles of herum gas must be added to the sample to obtain a volume of 6-4L?
Answer:
Explanation:
What objects in the solar system are larger
than Earth?
A. Mars, Mercury, and Venus
B. Neptune, Pluto, and Uranus
C. the inner planets and the Sun
D. the outer planets and the Sun
Answer:
d
Explanation:
the outer planets are uranus neptune jupiter and saturn also the sun all way bigger than the earth
What statement describes an electrolyte?
Which of the following is the correct name for CCl4? O A. Carbon chlorine O B. Carbon tetrachloride O C. Carbon chloride D. Carbon tetrachlorine
Why is sea water more dense than tap water? Give than explanation for these differences pleaseeee don’t copy off the internet :( I really need a good answer for this
Answer:
See below ~
Explanation:
Sea water has a high amount of salt present in it. The density of salt is higher than that of water. It dissolves in water, thereby increasing its density. Hence, this is why sea water has a higher density than tap water.
Answer:
sea water have high density and also they're moving from one side to another more than tap water
tap water have less density and also they're not moving ever they ain't move than sea water
Commercial agriculture can often lead to water-quality problems. In one to two sentences, explain how two of those problems occur.
anyone ?????
Commercial agriculture can lead to water-quality problems because water can be used for irrigation and washing chemical products.
What is commercial agriculture?The term commercial agriculture makes reference to the techniques to produce high yields in extensive crops.
Commercial agriculture may lead to contamination problems due to the use of herbicides and pesticides.
In conclusion, commercial agriculture can often lead to water-quality problems because water can be used for irrigation and washing chemical products.
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. How many ethyl groups are in the molecule 3, 3-diethylpentane?
O 1 groups
O 3 groups
O 4 groups
O2 groups
Answer:
2 groups
Explanation:
The molecule 3, 3-diethylpentane has 2 ethyl groups because the prefix di- means that there are 2 homogeneous substituent groups present in the molecule.
What does the atomic weight (mass number) of an element represent? ____________________________ .
Answer:
The atomic weight of an element represents the ratio of the average mass of atoms of a chemical element.
ANYONE PLEASE HELP BY THURSDAY!!
Bodies of water, such as ponds, freeze from top to bottom, forming a floating sheet of ice. This can help aquatic organisms survive during cold winter months. Which of the following statements explains why the ice floats on the
Surface of the pond?
A- the ice molecules have higher kinetic energy then the liquid molecules, causing them to float
B- the crystalline structure of solid ice makes it less dense than liquid water
C- as water freezes ionic bonds form between water molecules preventing the ice from sinking below the surface
Answer:
c
Explanation:
i dont have one
Is water from a river or from a well more likely to be clean to drink?
Water from a well is more likely to be clean to drink as compared to the water from river.
What are the sources of drinking water?Source water refers to bodies of water that contribute water to public drinking water sources and private wells (such as rivers, streams, lakes, reservoirs, springs, and ground water).
Water which came from underground sources are clean and well to drink as no impurities were present in that, whereas the water from rivers are not that much of clean as many human activities make them impure.
Hence water from well is clean to drink.
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Climate change.Write a full note on it
Climate change refers to long-term shifts in temperatures and weather patterns. These shifts may be natural, such as through variations in the solar cycle. But since the 1800s, human activities have been the main driver of climate change, primarily due to burning fossil fuels like coal, oil, and gas.
Burning fossil fuels generates greenhouse gas emissions that act like a blanket wrapped around the Earth, trapping the sun’s heat and raising temperatures.
Examples of greenhouse gas emissions that are causing climate change include carbon dioxide and methane. These come from using gasoline for driving a car or coal for heating a building, for example. Clearing land and forests can also release carbon dioxide. Landfills for garbage are a major source of methane emissions. Energy, industry, transport, buildings, agriculture, and land use are among the main emitters.
Nowadays the ice is melting more rapidly, this can cause a rise in water/ocean. The forests are drying up faster, species populations are declining rapidly. So we must take action before it is too late.
Thank you.
HAVE A NICE TIME
stay safe
What do you think will happen to the ecosystem if all the coral reefs are destroyed?
According to science what can we say about elements
Answer:
Elements were formed from a supernova in space that was so powerful, it gave us almost all the elements we have today.
Select the mass of naoh that is necessary to neutralize 8. 90 mol hcl(aq)
The mass of NaOH that is necessary to neutralize 8.90 mol of HCl is 356 grams.
How we convert moles into mass?Mass of any substance will be calculated from moles by using the below equation as:
n = W/M, where
W = required mass
M = molar mass
Neutralization reaction will be:
NaOH + HCl → NaCl + H₂O
From the stoichiometry it is clear that 1 mole of NaOH is required to neutralize 1 mole of HCl, so that 8.90 moles of NaOH is needed.
Mass of 8.9 moles of NaOH = (8.9mol)(40g/mol) = 356g
Hence required mass of NaOH is 356 grams.
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Calculate the mass percent of a solution prepared by dissolving 17. 2 g of nacl in 149 g of water
Answer:
10.72 %
Explanation:
17.9/(17.9+149)=.1072 = 10.72%
For which part of the engineering process would the use of statistics to analyze data about a new drug test be helpful?
A. Making a plan
B. Identifying a need
C. Evaluating the results
D. Testing the solution
C. Evaluating the results.
Explanation:
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