How much of a sample remains after five half-Iives have occurred?
1/5 of the original sarmple
1/25 of the original sarmple
1/32 of the original sample
1/64 of the original sample
Answer:
1/32 of the original sample
Explanation:
edgunity got it.
which of the following turns blue with a universal indicator (Litmus paper)
1. all
2. salt
3. base
3. acid
base
This is the answer
I need help who actually helps will get brailiest
Answer:
1. Pollution caused the bark to become darker.
2. The light-colored peppered moth had a higher chance of survival
3. The dark-colored peppered moth had a higher chance of survival
4. During the Industrial Revolution, the barks of trees got darks, causing the moths to be seen easily on a dark background. Now predators were more likely to eat the lighter cloured moths as they were easier to find. Since fewer light-colored moths were surviving, there was a smaller likelihood of light moths surviving long enough to reproduce. Since there were fewer light-colored moths, the dark-colored moths had less competition and were able to reproduce quickly.
5. Sunny, warm place: I live in a place with lots of light and sunshine, so it would be easier for light moths to blend in with their environment long enough to reproduce and thrive.
Dark, rainy Place: I live in a place with little light and sunshine, so it would be easier for dark moths to blend in with their environment long enough to reproduce and thrive.
Explanation:
what is the mass in grams of 120 liters at STP oh He gas
The mass of He gas = 21.428 g
Further explanationGiven
120 liters of He gas
Required
the mass in grams
Solution
Conditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, Vm is 22.4 liters/mol.
Mol for 120 L :
[tex]\tt \dfrac{120}{22.4}=5.357~moles[/tex]
Mass of He gas(MW=4 g/mol) :
[tex]\tt mass=mol\times Ar\\\\mass=5.357\times 4=21.428~g[/tex]
even about the food chain is correct?
Answer:
its C, because the cocunut tree gets energy from the sun and makes it into cocunut that is true
Explanation:
its C, because the cocunut tree gets energy from the sun and makes it into cocunut that is true
Question 10 of 25
Consider this reaction:
Mg(s) + 2H2O(1) ► Mg(OH)2(s) + H2(g)
What is the oxidation state of Mg in Mg(OH)2(s)?
A. +2
B. - 2
C. +1
D. 0
The oxidation number of Mg in Mg(OH)₂ is +2.
Hence, Option A is correct answer.
What is oxidation number?The oxidation state, or oxidation number, is defined as the hypothetical charge of an atom if all of its bonds formed with different atoms were fully ionic. It indicates the degree of oxidation of an atom in a chemical compound. Conceptually, the oxidation state may be negative, positive or zero.
Oxidation number of OH = -1
Let us suppose the oxidation number of Mg = x
Charge on compound = 0
We can write
x + 2(-1) =0
x-2=0
x = 2
Thus from the above solution we concluded that The oxidation number of Mg is +2.
Hence, Option A is correct answer.
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please help me i will give brain list tap the question
Answer:
molecular formulas of the hydrocarbons
Answer:
coh3 and xxxxxxxxxxxxx
1. Which groups of the periodic table constitute p-block?
g 30.0 mL of a buffer is made by mixing 20.0 mL of 0.10 M HNO2 and 10.0 mL of 0.10 M NaOH solution. What is the pH of this buffer after 0.04 mL of 10.0 M hydrochloric acid are added to it
Answer:
pH = 2.98
Explanation:
pKa of HNO2 is 3.35
HNO2 reacts with NaOH as follows:
HNO2 + NaOH → NaNO2 + H2O
Where moles of NaOH added are equal to NaNO2 produced
And initial moles of HNO2 - Moles NaOH = Moles HNO2
Initial moles HNO2:
0.0200L * (0.10mol/L) = 0.00200moles HNO2
Moles NaOH = Moles NaNO2:
0.0100L * (0.10mol/L) = 0.00100 moles NaOH = Moles NaNO2
Moles HNO2:
0.00200moles - 0.00100moles = 0.00100 moles HNO2
Then, the added HCl reacts with NaNO2 producing HNO2:
HCl + NaNO2 → HNO2 + NaCl
Where moles added of HCl are moles of HNO2 produced and initial moles of NaNO2 - moles of HCl = Moles NaNO2
Moles HCl:
4x10⁻⁵L * (10.0mol / L) = 0.00040moles HCl = Moles of HNO2 produced
Moles HNO2:
0.00100moles + 0.0004moles = 0.0014moles HNO2
Moles NaNO2:
0.00100moles - 0.0004moles = 0.0006moles NaNO2
With these moles and H-H equation we can solve for the pH of the buffer:
pH = pKa + log [NaNO2] / [HNO2]
Where pH is pH of the buffer
pKa is pKa of HNO2: 3.35
[] are moles of each species:
Replacing:
pH = 3.35 + log [0.0006moles NaNO2] / [0.0014moles HNO2]
pH = 2.98
A. C5H14
B. C5H12
C. C6H14
D. C6H12
Answer:
C. C₆H₁₄
General Formulas and Concepts:
Chemistry - Atomic Structure
Writing CompoundsExplanation:
To find the molecular formula of the model, you simply count and add up the same elements together.
We see that we have 6 carbons and 14 hydrogens. Therefore our answer is C. C₆H₁₄
Whats the difference between an atom and an ion?
An atom is the fundamental unit of matter and it contains an equal number of protons and electrons in its nucleus which makes it electrically neutral. An ion however, is an atom containing an unequal number of protons and electrons which means it will either carry a net positive charge or negative charge depending on whether there are more electrons or protons.
Answer:
atoms are neutral or they have equal number of proton and electron but ions can be cation(positively charged) or anion(negatively charged) based on the number of electron the atom lose and gain respectively
AP Chemistry
25.5 g of methane burns in the combustion reaction below. How much water is produced in this reaction? CH4 + 202 -- CO2 + 2H20
A. 22.69
B. 57.39
C. 510g
D. 3.18 9
Answer:
B
Explanation:
CH4 + 2 O2 → CO2 + 2 H20
12 + I X 4 → → 2 ( I X2 + 16 )
16 → → 36
25, 5 → → ?
amount of H2O = 36 X 25,5 / 16 = 57. 39
One mole or 16 g of methane gas reacts with excess oxygen to give 2 moles or 36 g of water. Then, the mass of water produced from 25.5 g of methane is 57.3 g.
What is combustion?Combustion is the reaction of a gas with the atmospheric oxygen producing water and carbon dioxide. The hydrocarbon gases such as methane, ethane etc easily undergo combustion reaction.
As per the given balanced reaction, one mole of methane gas CH4 produces two moles of water.
molar mass of methane = 16 g/mol
molar mass of water = 18 g/mol
mass of 2 moles of water = 36 g.
Hence, 16 g methane gas produce 36 g of water.
The mass of water produced from 25.5 grams of methane gas is then calculated as follows:
mass of water = 25.5 × 36 / 16 = 57.3 g.
Therefore, 57.3 g of water is produced in this reaction from 25.5 g of methane.
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Can someone please help me with my science research I kind of need help in a few things that I listed, I’m currently working on this element which is called Curium if anyone can help me out please do, thanks. Anyway here’s the questions:
Where can it be found?
What is its importance? What are its uses?
Answer:
For your first question, Curium does not occur naturally on Earth, meaning that it is not produced naturally on Earth. However, it can be formed in nuclear reactors.
For your second question, Curium has been used to provide power to electrical equipment used on space missions, but doesn't seem to be that important overall.
Explanation:
Hope this helped!
Please please please please please help I need to get this done please
Answer:
atoms
Explanation:
atoms combines to form compound
Explore: Find an example of each of the following in the Gizmo:
A.
An example of no chemical reaction occurring:
B.
A reaction that produces an acid:
C.
A reaction that produces a base:
D.
A reaction that uses a catalyst:
Answer:
B
Explanation:
How many HCl molecules and moles are there in 3.65 grams of
hydrogen chloride at normal conditions?
Answer:
0.6022×10²³ molecules
Number of moles = 0.1 mol
Explanation:
Given data:
Mass of HCl = 3.65 g
Number of molecules = ?
Number of moles = ?
Solution:
Number of moles:
Number of moles = mass/molar mass
Number of moles = 3.65 g/36.45 g/mol
Number of moles = 0.1 mol
Number of molecules:
1 mole of any substance contain 6.022×10²³ molecules
0.1 mol × 6.022×10²³ molecules/ 1 mol
0.6022×10²³ molecules
Which of the following provides evidence for past tectonic plate motions?
A. Matching rock type and rock formations can show the way the continents were once attached.
B.Glacial evidence has been found in areas where glaciers could not exist if the continents were in their current location.
C.Ancient life forms preserved as fossils can tell us what organisms existed and where they were. Matching the fossils can show that land masses were once connected.
D. All of the above.
Answer:
D
Explanation:
If there are 2 of the same rocks on two continents, that shows that they were once merged. If there is glacial existence in places where glaciers would’ve melted (Like Africa has glacial existence from Antarctica ) this shows that continents were once merged. If life forms preserved as fossils were matched on 2 different continents this shows that all the continents were once merged.
Answer:
so i am doing this and i need help what did u get for number 1
Explanation:
its the first question
What is the molarity of a 4.447 L solution
that is made from 13.53 g of NaCl?
Answer in units of M.
Answer:52M
Explanation:
use S= 1000w/ MV
Here, s= molarity
w= the amount of NaCl
M= the atomic mass of NaCl
V= the volume of solution
lewis structure for hypochlorus acid
write five characteristics of good government?
Explanation:
giving equal opportunity,making good governance, maintaining peace and harmony among people, other try to write by your self
Between which two objects is gravitational attraction the greatest?
between the penny and the small pot
between the book and the cereal box
between the small pot and the book
between the paper clip and the penny
Answer:
Between the small pot and the book
Explanation:
Since gravitational force is influenced by the mass of an object, the higher the mass of two objects, the stronger the gravitational force.
Thus, the force between the pot and the book is strongest, since the two have the highest mass.
Have a nice day!
1. The gases SO2, O2 and SO3 are allowed to reach equilibrium at a constant temperature. The equilibrium constant for the reaction
2SO2(g) + O2(g) -> 2S03(g)
is 1.6 x 104 atm-1
a) Calculate the value of Kp for the reaction
SO2(g) + ½O2(g) -> SO3(g)
(b) The equilibrium constant for the dissociation of Pcl5(g) to form PCl3(g) and Cl2(g) is
0.04 at 250°C. An equilibrium mixture contains 0.20 mol PC13 and 0.12 mol Cl, in a
4000 cm container.
i) Write the chemical equation.
ii) Calculate the concentration of PCIs in this container.
Answer:
a)
[tex]K_2=1.3x10^{2}atm^{-1/2}[/tex]
b)
[tex]PCl_5\rightarrow PCl_3+Cl_2[/tex]
[tex][PCl_5]=0.0375M[/tex]
Explanation:
Hello!
a) In this case, since we can see that the second reaction is equal to the half of the first reaction, we can relate the equilibrium constants as shown below:
[tex]K_2=K_1^{1/2}[/tex]
Thus, by plugging in the the equilibrium constant of the first reaction we obtain:
[tex]K_2=(1.6x10^4atm^{-1})^{1/2}\\\\K_2=1.3x10^{2}atm^{-1/2}[/tex]
b) In this case, for the described reaction we can write:
[tex]PCl_5\rightarrow PCl_3+Cl_2[/tex]
Thus, the corresponding equilibrium expression is:
[tex]K=\frac{[PCl_3][Cl_2]}{[PCl_5]}[/tex]
In such a way, since we know the equilibrium constant and the concentrations of PCl3 and Cl2 at equilibrium, we can compute the concentration of PCl5 at equilibrium as follows:
[tex][PCl_5]=\frac{[PCl_3][Cl_2]}{K}\\[/tex]
[tex][PCl_5]=\frac{\frac{0.20mol}{4L} *\frac{0.12mol}{4L} }{0.04}[/tex]
[tex][PCl_5]=0.0375M[/tex]
Best regards!
Need help now
Approximate half-life
Radon-222 = 4 days
A sample contains 18mg of radon-222. You estimate that this is 0.01% of the original isotope. How many half-lives have passed?
13 half-lives have passed
Further explanationGeneral formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
t1/2 = 4 days
Nt=18 mg (0.01% of the original isotope)
18 mg (Nt) = 0.01% No
No = the original isotope :
[tex]\tt No=\dfrac{100}{0.01}\times 18~mg=180,000[/tex]
The duration of decay (T) :
[tex]\tt \dfrac{Nt}{No}=\dfrac{1}{2}^{T/4}\rightarrow Nt=0.01\%No[/tex]
[tex]\tt 0.01\%=\dfrac{1}{2}^{T/4}\\\\10^{-4}=\dfrac{1}{2}^{T/4}\\\\(\dfrac{1}{2})^{13}=\dfrac{1}{2}^{T/4}\\\\13=T/4\rightarrow T=52~days[/tex]
Half-lives passed :
[tex]\tt \dfrac{52}{4}=13~half-lives[/tex]
Which of these correctly describes the energy that makes the carousel turn
Answer:
F
Explanation:
A carousel can be made to rotate using different sources of energy. One may decide to use electric energy, manual effort, water energy or heat energy as in a candle carousel.
When the candle is lit, heat energy is supplied and warm air rises heating up the air near the carousel eventually causing it to start rotating.
Hence heat from the candle leads to a current of warm air that rises up, causing the carousel to start rotating.
How many ions are in
1.50 grams of Na+
Answer:Multiple the moles of Na2 SO4 that you found just
Explanation:
Ions are formed by gaining and donating the valence electrons from the outer shells. Sodium has an extra electron and forms cations. In 1.5 grams of Na⁺, there are 0.0652 moles ions.
What are cations?Cations are said to be the ions that are formed by donating electrons from their valence shell. They tend to donate their electrons to form ionic bonds with another atom that accepts the electrons.
The mass and the molar mass of the cation can be used to calculate the number of moles contained in the atom or the ion.
Given,
Mass of sodium ions = 1.50 grams
The molar mass of sodium ions = 22.98 amu
The number of moles of sodium cation is calculated as:
Moles (n) = mass ÷ molar mass
n = 1.50 ÷ 22.98
= 0.0652 moles
Therefore, 0.0652 moles are present in 1.50 grams of sodium ions.
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what are the functional groups in tramadol
Answer:
1. ether group R-O-R
2. benzene ring
3. 3°- alcohol
4.3°- amine group N attached to 3 groups rather than H
compare the amount of heat required to vaporize 200 gram sample of h2o at its boiling point to the amount of heat required to melt 200 gram sample of h2o at its melting point
Answer:
The enthalpy of vaporization of H2O is higher than the enthalpy of fusion of H2O, therefore vaporizing the same mass of H2O would require more heat/energy than melting the same mass of H2O.
hope it helps!
The largest Alkali metal is ?
Answer:
cesium is the largest alkali metal.
Explanation:
Answer:
Cesium
Explanation:
Cesium is the largest atom among alkali metal.
how does increasing the height of an object affect its mechanical energy
Answer:
The amount of work required to raise the TV from point A to point B is equal to the amount of gravitational potential energy the TV gains from its height above the ground. This is generally true for any object ...
Calculate the pH for each H+ concentration.
[H+] = 1 x 10-8 M
pH =
---
[H+] = 0.001 M
pH
[H+] = 1 x 10-12 M
pH =
Answer:
The answer of 1×10 -8 is 2