How many atoms are in 3.2 pg of Ca? The molar mass of Ca is 40.08
g/mol.
Answer:
4.81×10¹⁰ atoms.
Explanation:
We'll begin by converting 3.2 pg to Ca to grams (g). This can be obtained as follow:
1 pg = 1×10¯¹² g
Therefore,
3.2 pg = 3.2 pg × 1×10¯¹² g / 1 pg
3.2 pg = 3.2×10¯¹² g
Therefore, 3.2 pg is equivalent to 3.2×10¯¹² g
Next, we shall determine the number of mole in 3.2×10¯¹² g of Ca. This can be obtained as follow:
Mass of Ca = 3.2×10¯¹² g
Molar mass of Ca = 40.08 g/mol
Mole of ca=.?
Mole = mass /molar mass
Mole of Ca = 3.2×10¯¹² / 40.08
Mole of Ca = 7.98×10¯¹⁴ mole.
Finally, we shall determine the number of atoms present in 7.98×10¯¹⁴ mole of Ca. This can be obtained as illustrated below:
From Avogadro's hypothesis,
1 mole of Ca contains 6.02×10²³ atoms.
Therefore, 7.98×10¯¹⁴ mole of Ca will contain = 7.98×10¯¹⁴ × 6.02×10²³ = 4.81×10¹⁰ atoms.
Therefore, 3.2 pg of Ca contains 4.81×10¹⁰ atoms.
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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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.
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
if you know any answer to this pls help out I'll give brainiest plus a lot of points
Answer:
I cant see it clearly
Explanation:
:(
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
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
Question 2
Calculate the velocity of a pickup truck with a de Broglie wavelength of 1.27 10-38 m and a
mass of 2347 kg
Explanation:
de Broglie wavelength= h/mv
v=h/m x de Broglie wavelength
v= (6.626× 10^-34)/ (2347× 1.27 × 10^-38)
v= 22.229 m/s(according to Google scientific calculator)
am sorry I don't hv a calculator at hand
1) The equilibrium constant Kc of the reaction
A + B ⇄ C + D is equal to 9.
If 0.4 mol of A and 0.4 mol of B are reacted, the number of moles of D formed is:
a) 0.30
b) 0.60
c) 0.40
d) 0.36
e) 0.18
Answer:
a) 0.30
Explanation:
Kc = [C] [D] / ([A] [B])
Set up an ICE table:
[tex]\left[\begin{array}{cccc}&Initial&Change&Equilibrium\\A&0.4&-x&0.4-x\\B&0.4&-x&0.4-x\\C&0&+x&x\\D&0&+x&x\end{array}\right][/tex]
Plug in values and solve:
9 = x² / (0.4 − x)²
3 = x / (0.4 − x)
1.2 − 3x = x
1.2 = 4x
x = 0.3
What is the density of Radon (Rn) gas at a temperature of 100°C and a pressure of 0.75
atm?
Answer:
Density of Radon is 5.44 g/.
Explanation:
Given data:
Temperature of gas = 100°C (273+100 = 373 K)
Pressure of gas = 0.75 atm
Density of gas = ?
Solution:
First of all we will derive the formula.
We know that,
PV = nRT
and
n = m/M (m = mass, M = molar mass)
PV = (m/M) RT
PVM = (m/M) RT ×M
PVM = mRT
PVM/V = mRT/V
PM = dRT (m/V = d)
Now we will put the values in formula:
Molar mass of Radon is 222 g/mol .
0.75 atm ×222 g/mol = d× 0.0821 atm.L/mol.K ×373 K
166.5 atm.g/mol = d×30.62 atm.L/mol
d = 166.5 atm.g/mol / 30.62 atm.L/mol
d = 5.44 g/L
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
What is a material that you cannot see through called?
Answer:
metal
Explanation:
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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heating a solid candle wax
What is answer
Physical or chemecal
Answer:
it will change its physical property from solid into liquid
What is the atomic number of an atom?
Answer:
The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present).
Explanation:
The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present).
Explanation:
The atomic number is number on the right side
SnO2 + H2_Sn+ H20 plz help me
Answer:
Tin(IV) Oxide + Dihydrogen = Tin + Water
Explanation:
wasn't ez
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
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
An astronaut has a mass of 80kg how much mass does he weigh in Mars
Answer:
26.66kg
Explanation:
If a person has a mass of 80kg, then they will weigh 80kg x 9.8m/s^2 or 784 Newtons on the Earth. That same person would weigh 80kg x 9.8m/s^2/3 or 261.33 Newtons on Mars, which the person might think was 26.66 Kg (although he would be incorrect since his mass has not changed).
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.
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)
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
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
What is the difference between a mixture and a compound ??
Answer:
Explanation:
Compound are substances which can be formed by chemically combining two or more elements. Mixtures are substances that are formed by physically mixing two or more substances.
WILL GIVE BRAINLIEST. If the frequency of X-ray radiation is increased, what changes? I. The number of photons. II. The energy of the radiation. III. The amplitude of the wave. IV. The wavelength of the radiation. I and II I and III I and IV II and III II and IV.
Answer:
II and IV.
Explanation:
To know which option is correct, do the following:
Energy (E) and frequency (f) are related by the following equation:
E = hf
Where:
E is the energy.
h is the Planck's constant.
f is the frequency.
From the equation E = hf
Energy is directly proportional to the frequency. This implies that an increase in the frequency will also increase the energy and a decrease in the frequency will also decrease the energy.
Therefore, (II) in the question above is correct.
Velocity (v), wavelength (λ) and frequency (f) are related by the following equation:
v = λf
Divide both side by λ
f = v/λ
Thus, we can see clearly that the frequency is inversely proportional to the wavelength. This means that an increase in frequency will decrease the wavelength and a decrease in frequency will increase the wavelength.
Therefore, (IV) in question above is correct.
Thus, II and IV are the correct answers.
how are heavy elements such as carbon, oxygen,and neon formed during star formation?
Answer:
Neutron star collisions
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.!
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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