how many moles are in 2.91 × 10²² atoms of He?
Answer:
0.048 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{2.91 \times {10}^{22} }{6.02 \times {10}^{23} } \\ = 0.04833887...[/tex]
We have the final answer as
0.048 molesHope this helps you
calculate the volume of nitrogen gas produce by heating g of ammonia at 21c and 823 torr pressure
Answer:
final volume = 10.5 Liters N₂(g) at 21°C and 823Torr*
Explanation:
*Note=>No specified mass value of N₂(g) is defined in the problem. Therefore for a starting point, the gas sample is assumed to be 1.00 mole N₂(g) at STP conditions 22.4L
Determine volume of N₂(g) at 21°C(=294K) and 823 Torr (= 2.286 Atm).
Start with Volume of N₂(g) at 0°C and 1 Atm pressure => 22.4L and adjust to final volume of N₂(g) based upon 21°C(=294K) and 823 Torr (= 2.286 Atm).
V(final) = 22.4L(294K/273K)(360 Torr/823 Torr) = 22.4L(294/273)(360/823) = 10.55 Liters final volume.
Note: The volume of 1 mole (assumed) of any gas at STP (0°C/1 Atm) is 22.4 Liters. To convert to non-STP conditions, convert temperature and pressure factors (changes) that reflect what happens when the gas is expanded or decreased; but, these adjustments are taken independently for each variable of interest. The following notes explain.
For the increase in temperature from 0°C(=273K) to 21°C(=294K) one must apply a temperature ratio that will increase volume. That is, the change in volume due to the temperature change is 294K/273K. If a 273K/294K ratio were used the volume would have decreased. Not so for heating a sample of gas.
For the increase in pressure one should expect a decrease in volume. Therefore apply a pressure ration that will effectively decrease the volume of the gas. That is, to decrease a 22.4L sample at STP multiply the standard volume by a ratio of pressures that will decrease 22.4L to a smaller volume. That is, V(final by pressure effects) multiply by 360Torr/823Torr to decrease the STP VOLUME (22.4L) to the new non-standard volume. If 823Torr/360Torr were used, the final volume would not be smaller, but larger. Such is the physical effect of an increasing pressure change.
How does heredity explain how traits
are passed from one generation to the next?
Answer:
Heritable traits are known to be passed from one generation to the next via DNA, a molecule that encodes genetic information. ... Organisms inherit genetic material from their parents in the form of homologous chromosomes, containing a unique combination of DNA sequences that code for genes.
Explanation:
Baking soda with hydrochloric acid combine and bubbles form. Chemical or physical change.
Answer:
I believe it is a chemical change.
please helppppp!!!
The Periodic Table is arranged by _______ properties:metals (mostly to the ____ of table,) metalloids(along the _____, and nonmetals) ( mostly to the ____ of table) . It is also arranged by chemical properties, including reactivity. Elements in the same vertical group have the same number of _____ electrons, and elements in the same horizontal period have the same number of _____ shells.
Explanation:
physicalleftmiddlerightouter mostelectron shellsWhat kind of energy is required for photosynthesis to occur?
energy stored in chemical bonds
energy from nutrients in the ground
thermal energy
solar energyy
Answer:
Explanation:
Solar energy
Your answer is 100% Solar Energy,
Why saturated fatty acid can't create kink?
Explanation:
because of double bond within chemical foundation.
Answer:
Saturated fatty acids exhibit a linear structure while unsaturated fatty acids bend, or kink, due to double bonds within the chemical foundation.
Which type of weathering causes the mineral composition of rocks to change?
Chemical weathering
General weathering
Mechanical weathering
Permeable weathering
Answer: chemical weathering
Explanation: Chemical weathering is different from mechanical weathering because the rock changes, not just in size of pieces, but in composition. That is, one type of mineral changes into a different mineral. Chemical weathering works through chemical reactions that cause changes in the minerals.
Answer:
I am not very sure but I think it's chemical weathering
A light absorbing chemical has a molar absorptivity constant of 487 L/mol*cm. For a system with a 1.00 cm path length, what chemical concentration would result in a recorded % transmittance of 31.6?a. None of these b. 974 M c. 0.000649 M d. 0.00103 M e. 0.0649 M
Answer:
The right answer is Option d (0.00103 M).
Explanation:
The given values are:
T = 31.6
e = 487 L mol cm
length, l = 1 cm
As we know,
Absorbance,
[tex]A=2-log_{10}(percent \ T)[/tex]
[tex]A=2-log_{10}(31.6)[/tex]
[tex]A=0.5003[/tex]
By using the Beer's law, we get
⇒ [tex]A=ecl[/tex]
⇒ [tex]c=\frac{A}{el}[/tex]
On substituting the values, we get
⇒ [tex]=\frac{0.5003}{487\times 1}[/tex]
⇒ [tex]=0.001027 \ \frac{mol}{L}[/tex]
⇒ [tex]=0.00103 \ M[/tex]
which of these phrases best describes an ecosystem
Answer:
all the living organisms in a specific location 2. ...
Identify some biotic factors in the diagram.
Identify some biotic factors in the diagram.
Identify some biotic factors in the diagram.
Identify what this diagram represents? ...
Give one effect that an increase in the minnow population would have on the ecosystem.
Classify each of the following processes as spontaneous or nonspontaneous
A 25.0mL sample of an acetic acid solution is titrated with a 0.175M NaOH solution. The equivalence point is reached when 37.5mL of the base is added. The concentration of acetic acid in the sample was :_________.A) 0.263
B) 0.365
C) 0.175
D) 1.83×10−4
E) 0.119
Answer:
Explanation:
First of all, let's write the equation of the reaction.
CH₃COOH + NaOH ⇒ CH₃COONa + H₂O
The formula to be used here is CaVa/CbVb = na/nb
where Ca is the concentration of the acid (?)
Cb is the concentration of the base (0.175M)
Va is the volume of the acid (25 mL)
Vb is the volume of the base (37.5 mL)
na is the number of moles of acid (1)
nb is the number of moles of base (1)
Ca × 25/0.175 × 37.5 = 1/1
Ca = 0.175 × 37.5 × 1 /25 ×1
Ca = 0.263 M
The concentration of the acid in the sample was 0.263 M
The mass of an atom composed of 7 protons, 8 neutrons, and 7 electrons is
Answer:
Nitrogen
Explanation:
Please help I’ll mark brainliest!
How does the acid level of a lake affect how many fish live there?
The dependent and independent Variable?
Answer:
it affects by how many fishes it kills i think
Explanation:
HELP ME PLEASE!!!!!!!!
Consider the reaction between NaOH (aq) and H2SO4(aq). 1) Please write the balanced reaction equation.
2) What is the concentration of the sodium hydroxide solution if 25.0 mL of it required 15.8 mL of a 0.350 M sulfuric acid for complete reaction?3) What is the concentration of the sodium hydroxide solution if 25.0 mL of it required 15.8 mL of a 0.350 M sulfuric acid for complete reaction?
4) If 14.0 mL of a 1.250 M sodium hydroxide solution and 25.0 mL of a 1.10 M phosphoric acid were reacted, what is the theoretical mass, in g, of the water produced?
Answer:
Explanation:
2NaOH + H₂SO₄ = Na₂SO₄ + 2H₂O .
2 ) 15.8 mL of .35 M sulphuric acid will contain .35 x .0158 moles of sulphuric acid
= .00553 moles
1 mole of H₂SO₄ reacts with 2 moles of NaOH
.00553 moles of H₂SO₄ will react with 2 x .00553 moles of NaOH
= .01106 moles
.01106 moles were contained in 25 mL
so concentration of NaOH = .01106 / .025
= .4424 M .
4 )
3NaOH + H₃PO₄ = Na₃PO₄+ 3H₂O .
14 mL of 1.25 M NaOH will contain .014 x 1.25 moles = .0175 moles
25 mL of 1.1 M phosphoric acid = .025 x 1.1 moles = .0275 moles
.0275 moles of phosphoric acid will require triple moles of NaOH , but it is in short supply . So NaOH is limiting reactant .
water formed = .0175 moles .
= .0175 x 18 grams of water
= .315 grams .
In nature element Carbon is found with different physical properties.Which allotrope of carbon is shown in the figure ? प्रकृति में कार्बन तत्व अनेक विभिन्न भौतिक गुणों के साथ विविध रूपों में पाया जाता है। चित्र में कार्बन के कौन से अपररूप की रचना दिखाई गई है ? *
Captionless Image
ਹੀਰਾ /Diamond/हीरा
ਬਕਮਿੰਸਟਰਫੁਲਰੀਨ /Buckminsterfullerene/बकमिंस्टरफुलेरीन
ਗ੍ਰੇਫਾਈਟ /Graphite /ग्रेफाइट
ਇਨ੍ਹਾਂ ਵਿੱਚੋਂ ਕੋਈ ਨਹੀਂ / None of the above/इनमें से कोई नहीं
Answer:
Graphite
Explanation:
The structure of diamond is similar to that shown, but has a middle layer that is offset from the others. The structure of Buckminsterfullerene is that of a soccer ball, 60 atoms arranged in a 32-faced figure.
The structure shown matches that of graphite.
Which choice best explains how global winds are formed?
Answer:
what are the choices?
Explanation:
If two forces are heading in the same direction, we ______ them to calculate net force.
options:
add
or
subtract
Answer:
add
Explanation:
please help me asap
the gravity of the sun keeps them in their orbits just as the moon orbits the earth because of the pull of Earth's gravity the earth orbits the sun because of the pull of the sun's gravity
Which of the following conditions would speed up the rate of decomposition? (Select
more than one answer)
a. Temperature at 50 degrees fahrenheit
b. Being buried
c. Overweight body
d. A body with illness
e. Temperature at 95 degrees fahrenheit
Answer:
E and B
Explanation:
the warmer the weather the faster it will decompose, this why is why sometimes bodies last longer frozen, or in cool temperatures.
that statement takes a out.
An illness shouldn't effect a decomposing body
Weight also shouldn't effect a decomposing body
Being buried can make bodies decompose fast because of all the bugs and other animals that will get down there and decompose it faster
Answer: B,E
Which of the following graphs correctly shows the relationship between potential energy and internuclear separation for two hydrogen atoms
Answer:
D
Explanation:
The potential energy curve of a system of atoms define the potential energy of the atoms with respect to the inter-nuclear separation. The minimum point of the curve represents the equilibrium bond length of the bond.
The energy of the system depends on the distance between the two interacting atoms.
Looking at the potential energy curve for hydrogen molecule in option D, we can assert that a chemical bond indeed exists between the two atoms of hydrogen and the minimum point of the curve is the equilibrium bond length of the bond.
A common relation between potential energy and internuclear distance when stated, is applicable to the ground states of diatomic and polyatomic molecules.
The graphs that correctly shows the relationship between potential energy and internuclear separation for two hydrogen atoms is option d.The potential energy of two separate hydrogen atoms often becomes lower as they approach each other, and the single electrons on each atom are shared to form a covalent bond.
The bond length is regarded as the internuclear distance where the lowest potential energy is gotten. The strong attraction of each shared electron often stabilizes the system.
Learn more from
https://brainly.com/question/18484436
If an athlete weighs 159 lb and has 15.0% % body fat by weight, how many pounds of fat does the athlete's body contain?
Answer:
23.85
Explanation:
is over of percent over 100
[tex]\frac{x}{159}[/tex]x[tex]\frac{15}{100}[/tex]
15 x 159 = 2385
2385 ÷ 100 = 23.85
If an athlete weighs 159 lb and has 15.0% % body fat by weight, the athlete's body contains approximately 23.84 pounds of fat.
To calculate the number of pounds of fat in the athlete's body, we can use the following steps:
Convert the athlete's weight from pounds to kilograms:
159 lb × 0.4536 kg/lb = 72.1224 kg
Calculate the weight of the athlete's body fat:
72.1224 kg × 0.150 = 10.81836 kg
Convert the weight of body fat from kilograms to pounds:
10.81836 kg × 2.2046 lb/kg = 23.8447 lb
Therefore, the athlete's body contains approximately 23.84 pounds of fat.
Learn more about fats here:
https://brainly.com/question/8073542
#SPJ 2
What is the 8th term in the geometric sequence described by this explicit formula?
An=6×3(n-1)
A.2187
B.612,220,032
C.13,122
D.39,366
Answer: C
Explanation: Answered this same question on a test before
The United States is one country that does not fully use the metric system for measurement.
Yes or No
Answer: yes
Explanation:
1.
Based on the following information, arrange the A, B, C, and D from lowest to highest
activity (in order of increasing ability to act as reducing agents).
I. Only A, C and D react with 1 mol/L HCl to give H2(e).
II. When A is added to solutions of the other metal ions, metallic B and Care
formed but not D.
a) C
b) B
c) B
d) C
e) B
Order of metals from least reactive to most reactive: B <C <A <D
Further explanationReducing agents are substances that experience oxidation
Oxidizing agents are substances that experience reduction
The metal activity series is expressed in voltaic series
Li-K-Ba-Ca-Na-Mg-Al-Mn- (H2O) -Zn-Cr-Fe-Cd-Co-Ni-Sn-Pb- (H) -Cu-Hg-Ag-Pt-Au
The more to the left, the metal is more reactive (easily release electrons) and the stronger reducing agent
The more to the right, the metal is less reactive (harder to release electrons) and the stronger oxidizing agent
So that the metal located on the left can push the metal on the right in the redox reaction
Let's analyze the statement in the problem
I. Only A, C and D react with 1 mol/L HCl to give H₂(e)
M + HCl ⇒ MCl + H₂(MCl : alkali, MCl₂ : alkaline earth)
A, C and D can react with 1 mol / L HCl, meaning metals A, C and D are located to the left of element H (more reactive), and B in the right of element H
II. When A is added to solutions of the other metal ions, metallic B and C are formed but not D.
This means that metal A is more reactive than metals B and C, while D is more reactive than A, so metal D is the most reactive
An electron at rest is subjected to two simultaneous constant magnetic fields; one is in the ax direction and the other is in the ay direction. The electron will:__________
Answer:
never move
Explanation:
Just like an electric current, we can only see the effects of magnetism when an electron is subjected to two simultaneous constant magnetic fields.
An electron at rest that is subjected to a magnetic field will never move but only in an electric field. The electrons are subjected to an electric force collinear with the electric field but in the opposite direction (the charge is negative).The acceleration vector tends to be in the same direction as the force, opposite the electric field.
Neutron moderation is used to counteract:
O A. the heat generated during nuclear fission reactions.
O B. the chain reactions that naturally occur with uranium-235.
O C. the low concentration of uranium-235 in nature.
O D. the minimal chance that the newly formed neutrons of a fission
reaction are absorbed by more atoms.
Answer:
(D) The minimal chance that the newly formed neutrons of a fission
Explanation:
I got it right on A P E X
Answer:
D. the minimal chance that the newly formed neutrons of a fission
reaction are absorbed by more atoms.
Explanation:
took test
how many mole are in 5.25 × 10²⁵ atoms of Au
Answer:
87.21 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{5.25 \times {10}^{25} }{6.02 \times {10}^{23} } \\ = 87.209302...[/tex]
We have the final answer as
87.21 molesHope this helps you
