heating a solid candle wax
What is answer
Physical or chemecal
Answer:
it will change its physical property from solid into liquid
4. Which of the following is the most stable isotope?
Polonium-210
Uranium-237
Francium-227
Plutonium-238
Half-life
(hr)
3,310
162
0.04
768,000
A. Polonium-210
B. Uranium-237
C. Francium-227
D. Plutonium-238
Answer: D. Plutonium-238 is the most stable isotope
Explanation:
Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles (such as alpha (α), beta (β), gamma (γ) particles)
General formulas used in decay:
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
Half-life shows the time it takes for an atom to get half of its initial mass (to decay to half of its initial mass)
The longer the half-life indicates the stability of the atom
Half-life (hr) of isotopes :
Polonium-210 : 3,310
Uranium-237 : 162
Francium-227 : 0.04
Plutonium-238 : 768,000
The half-life value above shows that Plutonium-238 has the longest time, making it the most stable
The longer the half life of an isotope higher will be its stability. Here, among the given isotopes, plutonium - 238 has the greater half life. Hence it is the mist stable one.
What is half life ?Heavy unstable radioactive isotopes undergoes nuclear decay through the emission of charged particles such as alpha or beta. The unstable isotopes then converts to other stable nuclei or to isotopes with more half life.
Half life of a radioactive isotope is the time required to decay the half of initial amount of the isotope. It is inversely proportional to the decay constant of the nuclear decay.
Among the given isotopes, Pu-238 has the longer half life time. Longer half time means more time to get decayed by half then more stability. Thus, Pu-238 is the most stable one.
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WHICH IS WHICH?
Directions: In the given illustrations, identify which are elements and compounds. Write
your answer in the space below the illustration.
plssss i need answers plssssssssssssss its due tmrw
Answer:
- First: element.
- Second: Compound.
- Third: element.
- Fourth: Compound.
Explanation:
Hello.
In this case, since elements are composed the same atom and compounds are composed by two different atoms, we can see that:
- First: it is an element as each sphere seems to be the same.
- Second: It is a compound as two different type of spheres are shown, white and black, considering each sphere is a different element.
- Third: it is an element because the spheres are equal, in fact, it is a diatomic element as two atoms are joined per molecule.
- Fourth: It is a compound as well since each molecule has two colored spheres and one white sphere, meaning that it has two different atoms per molecule.
Best regards.!
Explain why according to the kinetic theory of matter there is a problem with the Celsius scale for temperature.
Answer:
The Celsius scale is currently defined by two different temperatures: absolute zero and the triple point of Vienna Standard Mean Ocean Water (VSMOW; specially purified water). Based on this, the relationship between Celsius and Kelvin is as follows: TCelsius=TKelvin−273.15 T Celsius = T Kelvin − 273.15 .
pleaseeeeeeeeeeee help me
Answer:
4740460000, or 4.74046*10^9
Explanation:
This is math i thnk
e means *10
[tex]5.63\cdot \:8.42\cdot \:10^{19-11}[/tex]
[tex]5.63\cdot \:8.42\cdot \:10^8[/tex]
[tex]10^8\cdot \:47.4046[/tex]'
<3
Red
ok so this is saying
5.63 x 10^19 * 8.42 x 10^-11 indicates a scientific notation
plug into your graphing calculator and you get 4740460000 but make it imto three sig figs so the answer is: 4.74 x 10^9
The appearance of the surface of a mineral when it reflects light is known as
Answer:
Explanation:
The appearance of the surface of a mineral when it reflects light is known as
Giant kelp has gas-filled sacs to help it float so it can do what?
collect more sunlight
send signals to other plants
trap small fish
move with the ocean waves
Answer:
collect more sunlight
Answer:
to collect more sunlight
Explanation:
I
go to CALIFORNIA VIRTUAL ACADEMY ONLINE SCHOOL WITH K12
plz help me the other was blurry I had to repost it
Answer:
HCN+CuSO4->H2SO4+Cu(CN)2
2,1,1,1
1.Add 2 to HCN it then becomes (H=2, C=2, N=2,) (had to add 2 cz on right side you had H2 in H2SO4)
2.1(nothing) cz on both sides we got 1Cu and 1SO4
3.1 cz again we have H2 on both sides and 1SO4 on both sides
4.1 cz we got 1Cu on both sides and 2C 2N on both sides (1st step)
How many different types of elements are there in acetone C3H6O?
Answer:
3
Explanation:
Answer:
10
Explanation:
A given volume of gas at a temperature of 100 K has a
pressure of 225 kPa. At a higher temperature, the same
volume of gas has a pressure of 450 kPa. At what
temperature does the gas have this higher pressure?
Answer:
200K
Explanation:
Pressure is directly proportional to temperature.
100=225
x=450
(100*450)/225=x
x=45000/225
x=200
Where are most of the metals found on the periodic table
Answer:
Left
Explanation:
Metals are located on the left of the periodic table, and nonmetals are located on the upper right. They are separated by a diagonal band of semimetals.
If I have 21,000 mL of gas at a temperature of 870C and a pressure of 101 atm, what will be the pressure of the gas if I raise the temperature to 1040C and decrease the volume to 15 liters?
Answer:
We have,
Initial volume is V
1
Initial temprature is T
1
=75
0
C
Initial pressure is P
1
So, final temprature is T
2
=273+75=348K
V
2
=V
1
−
100
15
V
1
=
100
85V
1
Applying the gas formula,
T
1
P
1
V
1
=
T
2
P
2
V
2
348
P
1
V
1
=
T
2
×100
2P
1
×85V
1
T
2
=
100
2×85×348
T
2
=591.6K
Round the value 44.981 g to three significant figures.
Answer:
45.0
Explanation:
Using the rules of rounding, we can round 44.981 to 45. We need that third sig fig though, so we add the trailing zero
The value 44.981 g to three significant figures is 45.0 g.
Significant figures, also known as significant digits, are the digits in a number that carries meaning in terms of precision and accuracy. They indicate the certainty or reliability of a measurement or calculated value.
To round the value 44.981 g to three significant figures, follow the rules for significant figures:
Identify the three most significant digits in the number. They are 4, 4, and 9.
Look at the digit immediately after the third significant digit. If it is 5 or greater, round up; if it is less than 5, round down.
In 44.981 g, the digit immediately after the third significant digit (9) is 8. Since 8 is greater than 5, round up.
Therefore, rounding 44.981 g to three significant figures gives us:
45.0 g.
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Which statement about Earth's core helps explain Earth's magnetic field?
-Earth's core is composed of magnets.
-Earth's core is composed of iron and nickel.
-The outer core is solid,
-The inner core is liquid and moving
Answer:
it should be B. earths core is composed of iron and nickel, if not let me know.
Answer: B. Earth's core is composed of iron and nickel.
Explanation: The inner core is solid so C and D are incorrect and A is incorrect because the core isn't made of magnets so it has to be B.
A student was asked to name an element that reacts like chlorine (Cl). Which element should the student name?
Answer:
Bromine (BR2)
Explanation:
Cl2 + Br2 = ClBr
A 13.58 g sample of a compound contains 8.67 g of iron, Fe, 1.60 g of phosphorus, P, and oxygen, O. Calculate the empirical
formula for the compound.
Answer:
[tex]Fe_3PO_4[/tex]
Explanation:
To do this, we find the moles of each element. We get around 0.155 moles of Fe, 0.051 moles of P, and 0.206 moles of O. We then divide each one by the smallest one (which is 0.051 moles of P). We then get 3 for Fe, 1 for P, and 4 for O. This correlates to the empirical formula of the compound.
The empirical formula for the compound is [tex]Fe_3PO_4[/tex] if a 13.58 g sample of a compound contains 8.67 g of iron, Fe, 1.60 g of phosphorus, P, and oxygen, O.
What is the empirical formula?
An empirical formula tells us the relative ratios of different atoms in a compound.
We need to calculate the number of moles:
Given data:
Mass of iron - 8.67 g
Mass of phosphorus -1.60 g
Mass of oxygen -3.31 g
Moles of iron - [tex]\frac{mass}{molar \;mass}[/tex]
Moles of iron - [tex]\frac{8.67 g}{56 g/mol}[/tex]
0.15 mole
Moles of phosphorus [tex]-\frac{mass}{molar \;mass}[/tex]
Moles of phosphorus - [tex]\frac{1.60 g}{31 g/mol}[/tex]
0.051 moles
Moles of oxygen -[tex]\frac{mass}{molar \;mass}[/tex]
Moles of oxygen - [tex]\frac{3.31 g}{16 g/mol}[/tex]
0.20 moles
Dividing each mole using the smallest number that is divided by 0.051 moles.
Fe:P:O :: 3:1:4
The empirical formula for the compound is [tex]Fe_3PO_4[/tex].
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Which is NOT a reason why we use the scientific method?
To have something to share with other scientists
To minimize any mistakes and bias.
Because my teacher said so
To maintain good record keeping
Answer:
C. Because my teacher said so
Hope this helps :)
Answer:
Because my teacher said so
Explanation:
You good? lol
If a liquid has a pH of 7 it is what?
Answer:
Neutral
Explanation:
A pH of 7 is neutral. A pH less than 7 is acidic. A pH greater than 7 is basic. The pH scale is logarithmic and as a result, each whole pH value below 7 is ten times more acidic than the next higher value.
Answer:
I believe it is neutral.
Explanation:
Since higher than 7 pH is alkaline, and lower than 7 pH is acidic.
Which of the following excited state electron configurations of C would require the longest wavelength of light to produce?
Question 23 options:
1s22s22p13s1
1s22s22p2
1s22s22p24s1
1s22s22p13p1
Answer:
Explanation:
Well ik its not math for this but for the first one if u add
22+22+13+1 u get 58
then second one 1+22+22+2=47
1+22+22+24+1=70
1+22+22+13+1=59
U notice how that most or some are all going up to 50 except the third one
So that means its 1s22s22p24s1
The longest wavelength is required for the excited state, 1s22s22p13s1.
According to the Bohr model, an atom absorbs energy and moves from a lower energy level to a higher energy level. Also energy is emitted when an electron moves from a higher to a lower energy level.
The lowest energy state of an atom is called the ground state. The excited state is a higher energy level. The smaller the energy difference between the energy levels, the longer the wavelength required for the transition.
Hence, the longest wavelength is required for the excited state, 1s22s22p13s1.
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Forces are measured in
Newton
Watt
Mass
Grams
Answer:
A
Explanation:
Force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newtons and represented by the symbol F.
Solve for Density using D=M/V
10. A toy has a mass of 45g and Volume of 10 CM3.What is it's density?
Answer:
4.5 g/cm^3
Explanation:
use formula d=m/v
45/10
d= 4.5 g/cm^3
SnO2 + H2_Sn+ H20 plz help me
Answer:
Tin(IV) Oxide + Dihydrogen = Tin + Water
Explanation:
wasn't ez
if you know the answer to any of these pls help out I'll give brainiest. also a lot of points
Answer:
5. Divergent boundaries. Divergent boundaries can make underwater ocean trenches.
An element has three isotopes: St-284 (34.60%), St-285 (21.20%), and St-288 (44.20%). What is its average atomic mass?
Answer: I believe that it’ll be 284.45
Explanation:
May have to double check but I’m pretty sure that’s correct sorry if it’s not
Write the complete ionic equation for the reaction that takes place when aqueous solutions of strontium hydroxide and lithium phosphate are mixed.
Answer : The net ionic equation will be,
[tex]3Sr^{2+}(aq)+2PO_4^{3-}(aq)\rightarrow Sr_3(PO_4)_2(s)[/tex]
Explanation :
In the net ionic equations, we are not include the spectator ions in the equations.
Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.
The given balanced ionic equation will be,
[tex]3Sr(OH)_2(aq)+2Li_3PO_4(aq)\rightarrow 6LiOH(aq)+Sr_3(PO_4)_2(s)[/tex]
The ionic equation in separated aqueous solution will be,
[tex]3Sr^{2+}(aq)+6OH^{-}(aq)+6Li^{+}(aq)+2PO_4^{3-}(aq)\rightarrow Sr_3(PO_4)_2(s)+6Li^+(aq)+6OH^{-}(aq)[/tex]
In this equation, [tex]Li^+\text{ and }OH^-[/tex] are the spectator ions.
By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.
The net ionic equation will be,
[tex]3Sr^{2+}(aq)+2PO_4^{3-}(aq)\rightarrow Sr_3(PO_4)_2(s)[/tex]
The complete ionic equation for the reaction between aqueous solutions of strontium hydroxide and lithium phosphate is:
3Sr²⁺(aq) + 6OH¯(aq) + 6Li⁺(aq) + 2PO₄³¯(aq) —> Sr₃(PO₄)₂(s) + 6Li⁺(aq) + 6OH¯(aq)
The complete ionic equation is simply an equation showing all available entities including the spectator ions present in the solution.
With the above information in mind, we shall write the complete ionic equation for reaction between aqueous solutions of strontium hydroxide and lithium phosphate. This can be obtained as follow:
In solution, strontium hydroxide, Sr(OH)₂ and lithium phosphate, Li₃PO₄ will dissociate as follow:
Sr(OH)₂(aq) —> Sr²⁺(aq) + 2OH¯(aq)
Li₃PO₄(aq) —> 3Li⁺(aq) + PO₄³¯(aq)
The reaction will proceed as follow:
Sr(OH)₂(aq) + Li₃PO₄(aq) —>
Sr²⁺(aq) + 2OH¯(aq) + 3Li⁺(aq) + PO₄³¯(aq) —> Sr₃(PO₄)₂(s) + 3Li⁺(aq) + 2OH¯(aq)
Balance the equation by writing 3 before Sr²⁺, 6 before OH¯, 6 before Li⁺ and 2 before PO₄³¯, to obtain the complete ionic equation as shown:
3Sr²⁺(aq) + 6OH¯(aq) + 6Li⁺(aq) + 2PO₄³¯(aq) —> Sr₃(PO₄)₂(s) + 6Li⁺(aq) + 6OH¯(aq)
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What is an individual living entity called?
tissue
cell
organism
organ
Answer:
it is organism the third one
How long does primary succession take? ty sm ily
write formulas: a) 3 nitrogen atoms, b) 2 phosphorus molecules // help please with these
Explanation:
a)3 N
b)2 P4
hope it will help u
The forces that hold atoms together in an element determine its
F. conductivity
G.melting temperature only
H.hardness only
J.melting temperature and hardness
Questions and Problems 22 When water is heated, the temperature eventually reaches a constant value and forms a plateau on the graph. What does the plateau indicate?
Answer:
It indicates phase changes: melting then later boiling.
Explanation:
On the heating curve of water, the plateau marks phase change transitions.The temperature remains constant during this period.The first phase change is melting of water.The second phase change is boiling of water to gas.