Answer: The smallest unit of matter.
Explanation:
Cobalt-60 can be used by scientists for the purpose of radioactive dating. Cobalt-60 has a half-life of 5,272 years. A fossilized rock originally contained 25 grams of Co-60. When tested, the rock only contains 6.25 grams of Co-60. Approximately how old is the item?
A) 2,600 years
B) 5,200 years
C) 10,500 years
D) 15,600 years
the correct answer is C
Answer:
C) 10,500 years.
Explanation:
The decay of cobalt-60 is a first order reaction.The rate constant of the reaction (k) in a first order reaction = ln (2)/half-life = 0.693/(5272 year) = 1.314 x 10⁻⁴ year⁻¹.The integration law of a first order reaction is:
kt = ln [A₀]/[A]
k is the rate constant = 1.314 x 10⁻⁴ year⁻¹.
t is the time = ??? years.
[A₀] is the initial percentage of cobalt-60 = 25.0 g.
[A] is the remaining percentage of cobalt-60 = 6.25 g.
∵ kt = ln [Ao]/[A]
∴ (1.314 x 10⁻⁴ year⁻¹)(t) = ln (25.0 g)/(6.25 g)
(1.314 x 10⁻⁴ year⁻¹)(t) = 1.386.
∴ t = 1.386/(1.314 x 10⁻⁴ year⁻¹) = 10,550 years ≅ 10,500 years.
Answer:
answer is c
Explanation:
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Which phrases describe the atmosphere? Check all that apply.
protects Earth’s surface
contains a mixture of gases and particles
includes organisms in the air, on land, and in water
consists of rocks, minerals, landforms, and Earth’s interior
comprises oceans, lakes, rivers, streams, and groundwater
The atmosphere is a bunch of air/gases that protect the Earth. Nothing living is included in the atmosphere. Therefore the answers are...
Protects Earth's surface
Contains a mixture of gases and particles
Hope this helped!
Answer: protects Earth’s surface
contains a mixture of gases and particles
includes organisms in the air, on land, and in water
Explanation:
An atmosphere is the layer of gases that surrounds the earth. It is composed of air masses that consists of variety of gases like water vapor, oxygen, nitrogen, and carbon dioxide. It also consists of particles of dust and pollutants.
The function of the atmosphere is to protect the earth surface from the incident infrared rays and ultraviolet rays coming from the sun. The atmosphere covers the land and water region. Therefore, the lives of organisms that survive in air, land and water depends on the atmosphere.
Which statement describes how heat flows from the coffee to the part of the spoon in the coffee?
Answer:
Heat flows from the coffee to the spoon through conduction
Explanation: I took did the lab assignment
Heat flows from the coffee to the spoon through conduction. Therefore, option C is correct.
Conduction is one of the three main modes of heat transfer, alongside convection and radiation. It refers to the transfer of heat energy through direct contact between objects or substances that are at different temperatures.
Conduction occurs more efficiently in materials that are good conductors of heat, such as metals, which have closely packed atoms and free electrons that can easily transfer thermal energy. Materials with poor conductivity, such as insulators like wood or plastic, impede the transfer of heat by conduction.
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Your question is incomplete, most probably the full question is this:
Which statement describes how heat flows from the coffee to the part of the spoon in the coffee?
A. Heat flows from the coffee to the spoon through radiation.
B. Heat flows from the coffee to the spoon through convection.
C. Heat flows from the coffee to the spoon through conduction.
D. Heat flows from the coffee to the spoon through radiation, convection, and conduction.
Need help on this ASAP !!!!
Answer:
2Na + K₂S → 2K + Na₂S. "replacement reaction"
Explanation:
To balance the equation, you should apply the law of conservation of mass for the equations.
The law of conservation of mass states that the no. of each atom is equal in both sides (reactants and products).
So, the given equation is balanced as:
2Na + K₂S → 2K + Na₂S.
It is a replacement reaction that Na replace K in K₂S.
That 2.0 moles of Na react with 1.0 mole K₂S to produce 2.0 of K and 1.0 mole of Na₂S.
The no. of all atoms is the same in both of reactants and products side.Na (2), K (2), and S (1).
Calculate the molarity of a saline solution prepared by dissolving 41.2g of sodium chloride in 550mL of water.
Answer:
1.282 M.
Explanation:
Molarity is defined as the no. of moles o solute dissolved in a 1.0 L of the solution.M = (no. of moles of solute) / (V of solution (L))
M = (mass/molar mass)of NaCl / (V of solution (L))
mass of NaCl = 41.2 g, molar mass of NaCl = 58.44 g/mol, V of solution = 550 mL = 0.55 L.
∴ M = (mass/molar mass)of NaCl / (V of solution (L)) = (41.2 g / 58.44 g/mol) / (0.55 L) = 1.282 M.
The number of moles of solute in 200.ml of a 0.500 m solution is
Answer:
I believe the answer is 0.100.
Explanation:
Hope my answer has helped you!
Final answer:
To find the number of moles in 200 ml of a 0.500 M solution, convert the volume to liters (0.200 L) and multiply by the molarity to get 0.100 moles of solute.
Explanation:
To calculate the number of moles of solute in a 200 ml solution with a molarity of 0.500 M, you would use the formula:
Number of moles (mol) = Molarity (M)× Volume (L)
First, it is critical to convert the volume from milliliters to liters, knowing that there are 1000 ml in a liter:
200 ml is equivalent to 0.200 L.Next, you would use the given molarity of the solution to determine the moles of solute:
Moles of solute = 0.500 mol/L×0.200 LMoles of solute = 0.100 molSo, the solution contains 0.100 mol of solute.
which is more reactive, Rubidium or Hydrogen?
Answer:rubidium is the second most reactive metal so it is more reactive than hydrogen
Explanation:
Final answer:
Rubidium is more reactive than hydrogen, especially when reacting with water. It is part of the alkali metals that are highly reactive due to their position in the periodic table, while hydrogen, despite its reactivity, is less reactive with water and forms covalent compounds.
Explanation:
Between rubidium and hydrogen, rubidium is more reactive when it comes into contact with water. This is demonstrated by the vigorous and instantaneous reaction that occurs when rubidium solid is added to water, often resulting in an explosion. This reactivity is due to its position in the periodic table as an alkali metal, which are known for their high reactivity with water. In contrast, hydrogen, although reactive with some elements, has a lower reactivity towards water and forms covalent compounds with various elements.
The chemical equation 2 Rb(s) + 2 H₂O(l) → 2 RbOH(aq) + H₂ (g) depicts this reaction more accurately than a reaction in equilibrium with a low concentration of hydronium ions, as it conveys the fast and vigorous nature of the interaction between rubidium and water. The alkali metals, which include lithium, sodium, potassium, rubidium, cesium, and francium are part of Group 1 of the periodic table and are known for their reactivity, especially with water.
I give brainliest pls help
Answer:
c
Explanation:
because the fire gives off radiation
Which statement is most likely a scientific law?
Answer:
Scientific laws aka the laws of science are statements that are based off of repeated experimentation and/or observations.
Explanation:
Hooke's Law of Elasticity is the principle of physics that states that the force needed to extend or compress a spring by some distance is proportional to that distance.
Answer :
C - The oldest layers of rock lie below newer layers of rock on Earth.
If the actual yield of a reaction is 37.6 g while the theoretical yield is 112.8 g what is the percent yield
The answer is:
The percent yield of the reaction is 32.45%
Why?To calculate the percent yield, we have to consider the theoretical yield and the actual yield. The theoretical yield as its name says is the yield expected, however, many times the difference between the theoretical yield and the actual yield is notorious.
We are given that:
[tex]ActualYield=37.6g\\TheoreticalYield=112.8g[/tex]
Now, to calculate the percent yield, we need to divide the actual yield by the theoretical and multiply it by 100.
So, calculating we have:
[tex]PercentYield=\frac{ActualYield}{TheoreticalYield}*100\\\\PercentYield=\frac{37.6g}{112.8g}*100=0.3245*100=32.45(percent)[/tex]
Hence, we have that the percent yield of the reaction is 32.45%.
Have a nice day!
We need to find what percent 37.6 is out of 112.8 .
First find what fraction of 112.8 it is: (37.6/112.8) = 1/3
Change the number to a percentage: (1/3 x 100) = (33 and 1/3) %
Need help asap!!!!! Plz
Answer:
153.8 g/mol.
Explanation:
The molar mass of a compound = ∑ atomic masses of atoms.
∴ The molar mass of CCl₄ = 1(atomic masss of C) + 4 (atomic mass of Cl) = (12.0 g/mol) + 4 (35.45 g/mol) = 153.8 g/mol.
Conc. H2SO4 has a density 1.9g/ml and is 99% H2SO4 by weight. Find molarity of solution
Answer: The molarity of the solution comes out to be 19.19 M.
Explanation:
We are given:
99% m/m . This means that 99 grams of sulfuric acid is present in 100 grams of solution.
Density of solution = 1.9 g/mL
To calculate the volume of the solution, we use the equation:
Density of solution = 1.9 g/mL
Mass of solution = 100 g
Putting values in above equation, we get:
To calculate the molarity of a solution, we use the equation:
Given mass of sulfuric acid = 99 g
Molar mass of sulfuric acid = 98g/mol
Volume of solution = 52.63 mL
Putting values in above equation, we get:
Hence, the molarity of the solution comes out to be 19.19 M.
1. One of the essential minerals in the human body is salt. How much salt is in the average adult human body?
A. 1 kilogram
B. 500 grams
C. 250 grams
D. practically none
This is often argued over, but most people agree it is somewhere within the 200s. So I think 250 is your best bet.
Yes I agree, the answer is C) 250 grams since the average human body contains around 200 grams.
Identify and DESCRIBE the main kinds of storms. EXPLAIN how each forms. answer plz
There are numerous types of storms, each of them having their own unique characteristics, and unfortunately all of them being able to cause a lot of damage. Some of them are:
- Derecho storms
These are series of storms that stretch for over 240 mph. They have winds of over 58 mph, and they are very unpredictable.
- Flooding
The flooding occurs when there's excessive rainfall that over-saturates the water bodies and the soil with water, causing floods.
- Hail storm
They occur in the warm periods, coming in the shape of circular-shaped ice stones. This type of storm causes lot of damage through the power of the ice stones.
- Snow storm
The snow storms occur in the cold periods. They are excessive snowfalls, often accompanied with strong winds, managing to pile up enormous amounts of snow in a short period of time.
- Hurricanes
They are one of the most dangerous storms. They bring in lot of rainfall, but also very strong winds that manage to pull out trees, vehicles, and damage houses.
During Trial 2, what allowed you to determine that aluminum was the limiting reactant? Check all that apply
Answer:
All of the aluminum dissolved.
The molar ratio of copper(II) chloride to aluminum was greater than 3:2, the equation’s molar ratio.
Explanation:
Answer:
b and e
Explanation:
i just got it right
1. Balance the following decomposition of NaHCO3.
NaHCO3 →
Na2CO3 +
CO2 +
H2O
Explanation:
Plato (This message is here to bypass the word limit thingy)
If you have 100 grams of a radioactive isotope with a half life of 10 years how much of the isotope will you have left after 10 years
Answer:
50.0 g.
Explanation:
It is known that the decay of a radioactive isotope isotope obeys first order kinetics. Also, it is clear that in first order decay the half-life time is independent of the initial concentration.Half-life time is the time needed for the reactants to be in its half concentration.If reactant has initial concentration [A₀], after half-life time its concentration will be ([A₀]/2).So, the mentioned radioactive isotope after 10 years will have (100/2 = 50.0 g).Thus, the amount of radioactive isotope is 50.0 g.
We want to find how much of a radioactive isotope we will have after a given time, given that we know the half life of the isotope.
After 10 years, there will be 50 grams of the isotope.
The half life of a given quantity is defined as the time such that the quantity is reduced ot its half.
So if we initially have a quantity A with a half time T, after the time T our quantity will be A/2.
Now we have 100 g of a radioactive isotope with a half life of 10 years. Then after that time, 10 years, we will have half that mass of isotopes.
This is 100g/2 = 50g
After 10 years we will have 50 grams of isotopes.
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Answer:
2KClO₃ → 2KCl + 3O₂. "decomposition reaction"
Explanation:
To balance the equation, you should apply the law of conservation of mass for the equations. The law of conservation of mass states that the no. of each atom is equal in both sides (reactants and products). The balanced equation is:2KClO₃ → 2KCl + 3O₂.
It is a decomposition reaction that 1.0 reactant is decomposed to 2 products.
That 2.0 mole of KClO₃ are decomposed to produce 2.0 moles of KCl and 3.0 moles of O₂.
The no. of all atoms is the same in both of reactants and products side.K (2), Cl (2), and O (6).
How many liters of a 0.352 M solution of Ca(SO4) would contain 62.1 g of Ca(SO4)?
Answer:
1.3 L.
Explanation:
Molarity is the no. of moles of solute per 1.0 L of the solution.M = (no. of moles of CaSO₄)/(Volume of the solution (L))
M = 0.352 M.
no. of moles of CaSO₄ = mass/molar mass = (62.1 g / 136.14 g/mol) = 0.456 mol,
Volume of the solution = ??? L.
∴ (0.352 M) = (0.456 mol)/(Volume of the solution (L))
∴ (Volume of the solution (L) = (0.456 mol)/(0.352 M) = 1.296 L ≅ 1.3 L.
Provide the expressions for the equilibrium constant Keq:
CH4(g) + 2H2SE(g) ⇄ 4H2(g) +CSe2(g)
Answer:
Keq = [H₂]⁴[CSe₂]/[CH₄][H₂Se]².
Explanation:
The equilibrium constant expression is the ratio of the concentrations of the products over the reactants. For the reaction:CH₄(g) + 2H₂Se(g) ⇄ 4H₂(g) + CSe₂(g).
∴ Keq = [products]/[reactants] = [H₂]⁴[CSe₂]/[CH₄][H₂Se]².
The [H3O+] of a solution is 2.5 x10-7. What is the pOH of the solution?
Answer:
7.4.
Explanation:
∵ pH = -log[H₃O⁺].
∴ pH = -log(2.5 x 10⁻⁷) = 6.6.
∵ pH + pOH = 14.
∴ pOH = 14.0 - pH = 14.0 - 6.6 = 7.4.
PLEASE HELP!! 15 POINTS!!
Four stars of equal size emit the same amount of energy. The distance of these stars from Earth is shown in the following table.
Distance from Earth Star Distance from Earth (light years)
P 2.3
Q 7.8
R 6.5
S 3.2
What is the order of apparent magnitude of the stars, starting from the least to the greatest? Q, R, S, P
P, S, R, Q
R, S, P, Q
Q, P, S, R
Q, R, S, P is the order of apparent magnitude of the stars, starting from the least to the greatest.
Answer: Q, R, S, P
Explanation:
The apparent magnitudes of the star is the brightness calculated by an observer at a particular distance from the Earth. The smaller the distance between the star and the Earth, the greater the apparent brightness.
So , from the given distance (in light years), Q,R,S,P is the answer (least to the greatest apparent magnitude) (distance is greatest to least).
Answer:
Q, R, S, P is the order of apparent magnitude of the stars, starting from the least to the greatest.
Answer: Q, R, S, P
Explanation:
A 5.0-gram sample of gold and a 5.0-gram sample of iron both absorb exactly 25 calories of energy. The specific heat of gold is 0.03 cal/g°C. The specific heat of iron is 0.11 cal/g°C. Which of the following statements is true?
The gold sample will experience a greater increase in temperature.
The iron sample will experience a greater increase in temperature.
Both samples will experience the same increase in temperature.
Answer:
The gold sample will experience a greater increase in temperature.
Explanation:
To solve this problem, we can use the relation:Q = m.c.ΔT,
where, Q is the amount of heat absorbed by substance.
m is the mass of the substance.
c is the specific heat of the substance.
ΔT is the difference between the initial and final temperature.
∴ ΔT = Q /(m.c)
It is clear that ΔT is inversely proportional to the specific heat capacity of the object.
So, the object with the smallest specific heat capacity (gold) will have the greater increase in temperature.
The increase in T can be calculated for both objects:
For gold:
ΔT = Q /(m.c) = (25 cal)/(5.0 g)(0.03 cal/g°C) = 166.7°C.
For iron:
ΔT = Q /(m.c) = (25 cal)/(5.0 g)(0.11 cal/g°C) = 45.45°C.
So, the right choice is:The gold sample will experience a greater increase in temperature.
Answer:
The gold sample will experience a greater increase in temperature.
Explanation:
Select all that apply. Which of the following measurements have 3 significant figures? 0.0882 m 0.8820 m 8,820 m 882.0 m
8820 and 0.0882 have three sig figs
When a number has zeros in it I struggled a lot to determine if it what a sig fig or not. This is how I remember it:
If a zero is a sandwich between normal numbers it IS a sig fig
Zero's after the decimal ARE sig figs
***IMPORTANT! There is an exception to this one which I'll talk about next :)
Leading zeros (I believe that is what they are called) are NOT sig figs. This would be like the zeros in the following numbers:
0.2
0.03
0.000000000000000000006
If there are zeros after normal numbers and there is NO DECIMAL it is NOT a sig fig. This would be like the zeros in the following numbers:
630
3, 000
536, 329,600,000
Take a look at the other numbers:
0.8820 <<<This has 4 sig. figs.
882.0 <<<This has 4 sig. figs.
***Remember that if there is a pure decimal the zero in front of the decimal is NOT a sig fig and just a place holder. It isn't necessary and can always be taken away
Hope this made sense and helped!!!
The 8820 m and 0.0882 m have three significant figures
What are the rule to determines significant figures?There are rules are to be applied to determine the significant figures in a suitable quantity.
All non-zero digits are significant.Example : 23 cm ,2.3 cm , and 0. 23 cm all have two significant figures.
The zeros present to the of the first non-zero digit in the number are not considered as significant figures
Example: 0.033 has two significant figures and 0.00172 has three significant figures.
Zeros present between the two non-zero digits are significant.Example: 6601 has four significant figures.
Zeros at the right or end of the of the number are significant if it is present at the right side of decimal points.Example: 8.00 has three significant figures and 0.070 has two significant figures.
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How much force is required to lift a rock a vertical distance of 8 m if 80 j of work were done
we have
work done (W)= force(F) × displacemen(s)
or, 80= F× 8
or, F= 10 N
therefore, 10 N force is required to lift the rock.
Final answer:
To calculate the force needed to lift a rock 8 m when 80 J of work is done, use the formula W = F × d, resulting in a force requirement of 10 N.
Explanation:
To find out how much force is required to lift a rock a vertical distance of 8 m when 80 J of work were done, we can use the relationship between work done, force, and distance. The work done when lifting an object is defined by the formula W = F × d, where W is the work, F is the force, and d is the distance. In this case, W = 80 J and d = 8 m. By rearranging the formula to solve for F, we get F = W/d. Therefore, the force required to lift the rock is F = 80 J / 8 m = 10 N.
Predict the products formed by the double replacement reaction between CaCl2(aq) and Na3PO4(aq). Explain your reasoning.
Answer:
3CaCl₂ + 2Na₃PO₄ → Ca₃(PO₄)₂ + 6NaCl.
Explanation:
Double replacement reaction is a type of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products.The reaction between CaCl₂ and Na₃PO₄ is:3CaCl₂ + 2Na₃PO₄ → Ca₃(PO₄)₂ + 6NaCl.
Ca replaces Na in (Na₃PO₄ ) and forming Ca₃(PO₄)₂.
Na replaces Ca in CaCl₂ and forming NaCl.
So, the products of this reaction are Ca₃(PO₄)₂ and NaCl.
Consider the chemical equations shown here.
P4(s) + 3O2(g) → P4O6(s) ΔH1 = -1,640.1 kJ
P4O10(s) → P4(s) + 5O2(g) ΔH2 = 2,940.1 kJ
What is the overall enthalpy of reaction for the equation shown below?
Round the answer to the nearest whole number.
P4O6(s) + 2O2(g) --> P4O10(s)
Answer:
- 1300 kJ.
Explanation:
We should modify the given two reactions to reach to the final reaction:We should reverse the first reaction and so multiply its ΔH by (- 1):
P₄O₆(s) → P₄(s) + 3O₂(g), ΔH₁' = 1640.1 kJ.
The second reaction also should be reversed and so multiply its ΔH by (- 1):
P₄(s) + 5O₂(g) → P₄O₁₀(s), ΔH₂' = - 2940.1 kJ.
If we add the two reactions after modification, we get:
P₄O₆(s) → P₄O₁₀(s).
∴ ΔH = ΔH₁' + ΔH₂' = 1640.1 kJ + (- 2940.1 kJ) = - 1300 kJ.
Answer:
answer is -1300 on edge 2021
Explanation:
Based on the map which answer best explains major concern in the union governmental offices during the war
The major concern for the Union government offices during the war was that the Confederate states managed to win a battle in very close proximity to their capital Washington. The fact that the Confederate forces were so close to Washington, and the defenses of the capital were very strong at the moment, while the majority of the soldiers were at other locations and needed time to get back to defend it. This was bringing a big concern because if Washington was captured by the Confederate forces then the Union would have been in big trouble and suffer badly because of it.
Answer:
Moving battles farther up the Northeast coast
Explanation:
Moon is related to planet in the same way that planet is related to _____________. A. Orbit
B. Sun
C. Neptune
D. Dwarf planet
Answer:
sun
Explanation:
Final answer:
A moon orbits a planet, and a planet orbits the Sun, completing the analogy and indicating 'Sun' is the correct answer to fill in the blank.
Explanation:
The question requires drawing an analogy between celestial bodies based on their relationships within the solar system. A moon orbits a planet, and similarly, a planet orbits something else. The best answer to what a planet orbits is the Sun, which is at the center of our solar system.
We know that all the planets in our solar system, including Earth, revolve around the Sun. This is due to the Sun's gravitational pull, which keeps the planets in their respective orbits. Likewise, moons, including Earth’s moon, orbit their respective planets due to the gravitational pull of these planets.
Therefore, the analogy completes as follows: Moon is to planet as planet is to Sun. The correct choice is B. Sun.
• How can pollution affect water as a resource?
Answer:
Dead fish, birds, dolphins, and many other animals often wind up on beaches, killed by pollutants in their habitat.