Answer:
c. 0.37 moles
Explanation:
To find the number of moles (n) in a certain number of atoms of a substance, we divide the number of atoms by Avogadro number (nA), which is 6.02 × 10²³ atoms.
That is,
n = number of atoms ÷ 6.02 × 10²³
According to this question, there are 2.25 x 10²³ atoms of carbon (C). The number of moles contained in this carbon is as follows:
n = 2.25 x 10²³ ÷ 6.02 × 10²³
n = 2.25/6.02 × 10 (23 - 23)
n = 0.374 × 1
n = 0.374moles
HURRRY ASAP!!
An important consideration of the medical use of radioisotopes is how long they're active. Technetium-99 is a short-lived isotope of technetium with a half-life of 6 hours. If a patient is treated with technetium-99 for a PET scan, when will the patient have less than 1 percent of the original technetium-99 present?
A)
3 days
B)
40 hours
C)
6 hours
D)
0.00116 hours
How many moles of ammonia can be produced when 2.50 moles of hydrogen react?
Answer:
5/3 moles
Explanation:
3.moles.of H2 gives 3 moles of NH3
so 2.5 moles gives 5/3 moles.
Note:Apply simple. concept of unitary method.
Please somone help me with a chemistry question brainliest to whoever answers correctly and 20 points
Answer:
Polar
Explanation:
Electronegativity Difference:
0.7 Non-Polar Covalent = 0 0 < Polar Covalent < 2 Ionic (Non-Covalent) ≥ 2
Which two elements make up the greatest percentages by mass in Earth’s crust?
(1) oxygen and potassium
(2) oxygen and silicon
(3) aluminum and potassium
(4) aluminum and silicon
The most appropriate option is :
[tex]\hookrightarrow \bf2. \: \mathrm{ \underline{oxygen \: \: and \: \: silicon}}[/tex]
Since, they are the most abundant elements found in Earth's Crust.
Oxygen (46%)Silicon (28%)[tex]\circ { \underline{ \boxed{ \sf{ \color{green}{ \mathrm{hope \: \: it \: \: helps \: \: you .....}}}}}}∘[/tex]
What is the percentage by mass of solution formed by dissolving 36.0 grams of HCl in 98.0 grams of water?
73.1%
36.7%
26.9%
24.2%
Answer:
26.9%
Explanation:
I just took the test! :)
The percentage by mass of solution formed by dissolving 36.0 grams of HCl in 98.0 grams of water is 36.7%.
How to calculate percentage by mass?The percentage by mass of a solution can be calculated by dividing the mass of the solute by the mass of the solvent, then, multiplied by 100.
percent by mass = mass of solute/mass of solvent × 100
According to this question, 36.0 grams of HCl is dissolved in 98.0 grams of water. The percentage by mass is calculated as follows:
percent by mass = 36g/98g × 100
percent by mass = 36.7%.
Therefore, the percentage by mass of solution formed by dissolving 36.0 grams of HCl in 98.0 grams of water is 36.7%.
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PLEASE ANSWER URGENTLY!! What is the daughter particle if Uranium -234 undergoes beta decay? Write your answer in isotopic notation.
Answer:
²³⁴₉₃Np.
Explanation:
We can obtain the daughter particle as follow.
Let ⁿₓM represent the daughter particle.
Thus, the equation for the reaction is given below :
²³⁴₉₂U —> ⁿₓM + ⁰₋₁e
Next, we shall determine n, x and M. This can be obtained as follow:
234 = n + 0
234 = n
n = 234
92 = x + (–1)
92 = x – 1
Volume like terms
92 + 1 = x
93 = x
x = 93
ⁿₓM => ²³⁴₉₃M => ²³⁴₉₃Np
Thus, the equation for the reaction becomes:
²³⁴₉₂U —> ²³⁴₉₃Np + ⁰₋₁e
The daughter particle => ²³⁴₉₃Np
A presión de 3atm, 7L de un gas a temperatura constante experimenta un cambio ocupando un volumen de 0,5L ¿Cuál será la presión que ejerce? ayuda
Answer:
La presión que ejerce es 42 atm.
Explanation:
La ley de Boyle relaciona la presión y el volumen y dice que el volumen ocupado por una determinada masa gaseosa a temperatura constante, es inversamente proporcional a la presión.
La ley de Boyle se expresa matemáticamente como:
P*V=k
Ahora es posible suponer que tienes un cierto volumen de gas V1 que se encuentra a una presión P1 al comienzo del experimento. Si varias el volumen de gas hasta un nuevo valor V2, entonces la presión cambiará a P2, y se cumplirá:
P1*V1= P2*V2
En este caso:
P1= 3 atmV1= 7 LP2= ?V2= 0.5 LReemplazando:
3 atm* 7 L= P2* 0.5 L
Resolviendo:
[tex]P2=\frac{3 atm*7 L}{0.5 L}[/tex]
P2= 42 atm
La presión que ejerce es 42 atm.
Answer:10.5
Explanation:
3atm x 7L / 0,5L = 10.5
Quando bajamos el volmen sube la presion y cuando bajamos la presion sube el volumen
What are two examples of mechanical waves?
• Radio
• Water
• Light
•Sound
Answer:
radio and sound
Explanation:
Because they are waves in motion
Please help I have chemistry final
Answer:
Tick
1
2
4
6
Explanation:
magnesium is not a good conductor has some free electrons but it is not used that much in the industries because of other better alternatives.
You can tick number 5 as wlee. Good luck
Answer:
the answer is a
Explanation:
it'sa silver-white an earth metal
I'm having trouble with this one
Answer:
1) 7 moles
2) 82.4 grams approximately
PLEASE HELP SOMEONE !!!!!!!!!!!!!!!!!!!
Answer:
sodium
Explanation:
sodium has 11 electrons.
CaC0³ scientific name is?
Answer:
CaC0³ scientific name is Calcium carbonate
Explanation:
Have a great summer :)
Can someone please help me!!
Answer:
Explanation:
Hope this helps u!!
HELP ASAAAAP 40 MINS LEFT AAA!
Geometric isomers have profound effects on the physical properties of compounds. Naturally occurring fatty acids generally adopt a cis geometry. What's one physical property affected by this geometry?
A)
Color
B)
Taste
C)
Smell
D)
Melting point
1.2 Give two ways that somebody could get Salmonella food poisoning.
Answer: Raw meat, poultry and seafood. Feces may get onto raw meat and poultry during the butchering process. ...
Raw eggs. ...
Fruits and vegetables.
Explanation:
why do objects cool down
Answer:
wla dyan ang sagut ehh baka mali yan
circle the correct words to complete the sentences
1. Precipitation falls in these two forms: solid/liquid/gas
2. Evaporation changes gas/liquid water to ice (solid)/water vaoor (gas)
Answer:
1. solid and liquid
2.Evaporation changes liquid water to water vapour.
Answer: i don't know i just want points sorry can you blame me you would do the same too i know you
Explanation:
yay i got 5 points
which ancient African Kingdom is located in western Africa?
Answer:
Ghana Empire is was a kingdom in western Africa.
The Oyo Empire was the ancient African Kingdom is located in western Africa.
What is Oyo Empire?The Oyo Empire prospered on regional trade and became a key facilitator in moving slaves from Africa's interior to the coast and waiting European sailing ships, with its capital at Old Oyo near the River.
The human trade was so extensive that this region of Africa became known simply as the "Slave Coast."
Finally, despite all efforts, the Oyo Empire became a protectorate of the United Kingdom in 1888; its states ceased to exist as a superpower, and it never regained its prominence in the region.
During the colonial period, however, the Yoruba were one of Africa's most urbanized groups.
Thus, the ancient African kingdom of the Oyo Empire was located in western Africa.
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URGENT!!!
A 0.420 M Ca(OH)2 solution was prepared by dissolving 64.0 grams of Ca(OH)2 in enough water. What is the total volume of the solution formed? (4 points)
1.07 liters
1.23 liters
2.05 liters
2.18 liters
Answer:
2.05 L is the correct answer.
Explanation:
w = 64 g
c = 0.420 M
m = 40 + (16+1)×2 = 74
[tex]c = \frac{w}{m \times v} \\ \implies \: v = \frac{w}{c \times m} \\ = \frac{64}{0.420 \times 74} \\ = 2.05 \: \: liters[/tex]
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The volume of the solution is given below which can be calculated using the molarity formula.
d. 2.18 litres
Molarity:It is defined as the ratio of number of moles of solute to the volume of the solution.
It is given by:
M= n/V
What information do we have?
M= 0.420M
mass = 64.0 grams
Molar Mass= 74g/mol
To find:
Volume of solution=?
Calculation for number of moles:
n= m/ M
n= 64/70
n= 0.91 moles
Molarity= n/V
0.420 M= 0.91 moles /V
V= 0.91/ 0.420
V= 2.1768 litres
Thus, the volume of the solution is 2.18 litres.
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What is the molarity of a solution of 58.7 grams of MgCl2 in 359 ml of solution?
Answer:
1.72 M
Explanation:
Molarity is the molar concentration of a solution. It can be calculated using the formula a follows:
Molarity = number of moles (n? ÷ volume (V)
According to the information provided in this question, the solution has 58.7 grams of MgCl2 in 359 ml of solution.
Using mole = mass/molar mass
Molar mass of MgCl2 = 24 + 35.5(2)
= 24 + 71
= 95g/mol
mole = 58.7g ÷ 95g/mol
mole = 0.618mol
Volume of solution = 359ml = 359/1000 = 0.359L
Molarity = 0.618mol ÷ 0.359L
Molarity = 1.72 M
The equation below is for potassium oxide.
4K + O2 2K2O
What is the ratio of atoms of potassium to atoms of oxygen?
Answer:
The ratio of atoms of potassium to atoms of oxygen is 2:1
Explanation:
As the equation given is :
[tex]4K + O_2 -----> 2K_2O[/tex]The product formed is 2 moles of potassium oxide .
Amount of potassium atom in the potassium oxide is 2 atoms of potassium and amount of oxygen atom present here is 1 atom of oxygen .
But we have 2 moles of potassium oxide . So, the potassium and oxygen atoms will be multiplied by 2 .
Hence , we get 4 atoms of potassium and 2 atoms of oxygen .
Ratio of potassium to oxygen atoms is - 4:2
Therefore , 2:1
Answer:
2;1
Explanation:
5. A 5.00 g sample of an unknown substance was heated from 25.2 C to 55.1 degrees * C , and it required 133 to do so. Identify the unknown substance using the chart above.
show work please
Answer:
Aluminum
Explanation:
Given
[tex]T_1 = 25.2^oC[/tex]
[tex]T_2 = 55.1^oC[/tex]
[tex]m = 5.00g[/tex]
[tex]\triangle Q= 133J[/tex]
See attachment for chart
Required
Identify the unknown substance
To do this, we simply calculate the specific heat capacity from the given parameters using:
[tex]c = \frac{\triangle Q}{m\triangle T}[/tex]
This gives:
[tex]c = \frac{\triangle Q}{m(T_2 - T_1)}[/tex]
So, we have:
[tex]c = \frac{133J}{5.00g * (55.1C - 25.2C)}[/tex]
[tex]c = \frac{133J}{5.00g * 29.9C}[/tex]
[tex]c = \frac{133J}{149.5gC}[/tex]
[tex]c = 0.89\ J/gC[/tex]
From the attached chart, we have:
[tex]Al(s) = 0.89\ J/gC[/tex] --- The specific heat capacity of Aluminum
Hence, the unknown substance is Aluminum
A chemist mixed two substances together: a blue powder with no smell and a colorless liquid with a strong smell. Their repeating groups of atoms are shown below on the left. After they were mixed, the chemist analyzed the results and found two substances. One ending substance had the repeating group of atoms shown below on the right. Is the ending substance the same substance as the blue powder? What happened to the atoms of the starting substances when the ending substances formed
Answer:
Vanished completely.
Explanation:
The atoms of starting substances are transformed into the ending substances because the starting substances mixed with each other and turn into new substances. The starting substances i.e. reactants vanished completely when the ending substances means products are formed completely so we can say that the vanishing of ending substance happened when the ending substances are formed.
Calculate the shortest wavelength of the electromagnetic radiation emitted by the hydrogen atom in undergoing a transition from the n = 6 level.
Answer:
[tex]\lambda = 9.376*10^{-8} m[/tex]
Explanation:
From the question we are told that:
[tex]n=6level[/tex]
Generally the equation for Energy is mathematically given by
[tex]E=\frac{hc}{\lambda}[/tex]
Since
Energy difference will be maximum when electron return to ground state
And Shortest wavelength is emitted when there is largest energy difference
Therefore
[tex]1/\lambda = R* (\frac{1}{nf^2} - \frac{1}{ni^2})[/tex]
Where
[tex]R=Rydberg\ constant[/tex]
[tex]R = 1.097*10^7[/tex]
Therefore
[tex]1/\lambda = 1.097*10^7* ((\frac{1}{1^2} - \frac{1}{6^2})[/tex]
[tex]\lambda = 9.376*10^{-8} m[/tex]
A container with a specific volume “V” changes to “2V.” What happens to the average distance between gas molecules? Assume that pressure and temperature of the gas remain constant.
Explanation:
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Nitrogen and sulfur oxide gases originate from all of the following, EXCEPT
A . lightening Strikes
B. Volcano eruptions
C. Car exhaust
D . Plant Respiration ANSWER IT FOR 50 PIONTS!!!!!!!!!!!!!
Answer:
the answer is D (つ°ヮ°)つ （＾ω＾）
what are the characteristics or properties that you can use to classify elements
Answer:
The number of outermost energy level electrons ( valency electrons )
The atomic number
Hurry please. What are 2 Cell organelles? Provide 2 analogies for each What level of organization are you (a human) considered? Show me another example
Answer:
Nucleus and mitochondria. Organism.
Explanation:
The two main organelles are the nucleus and the mitochondria . The nucleus is boss of the factory(controls everything). The mitochondria is the power house of the cell (provides the energy). Humans are organisms (made of organs systems working together) . Another example is plants they are also organisms
The actual yield of a product in a reaction was measured as 4.20 g. If the theoretical yield of the product for the reaction is 4.88 g, what is the percentage yield of the product? (4 points) Question 17 options: 1) 82.6% 2) 84.2% 3) 86.1% 4) 88.0%
Answer:
3
Explanation:
remember the equation percentage yield = actual/ theoretical yield as
4.20/4.88 x 100
86.065 so 86.1.
hope this make sense:)
The percentage yield of the product is 86.1%. The correct option is 3) 86.1%
Calculating percentage yieldFrom the question, we are to calculate the percentage yield of the product
Percentage yield can be calculated from the formula,
[tex]Percentage \ yield = \frac{Actual\ yield}{Theoretical \ yield} \times 100\%[/tex]
From the given information,
Actual yield = 4.20 g
Theoretical yield = 4.88 g
Putting the parameters into the formula, we get
[tex]Percentage \ yield = \frac{4.20}{4.88} \times 100\%[/tex]
Percentage yield = 0.86065574 × 100%
Percentage yield = 86.065574%
Percentage yield ≅ 86.1%
Hence, the percentage yield of the product is 86.1%. The correct option is 3) 86.1%
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Describe the formation of calcium chloride (4 marks)
Answer:
It is an ionic compound that consists of one calcium cation Ca2+ and two chlorine anions. The bivalent calcium metal forms an ionic bond with two chlorine atoms. The formation of cacl2 happens mainly by reacting limestone (CaCo3) with hydrochloric acid (HCl).