Answer:
2.79 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{1.68 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 2.790697 ...[/tex]
We have the final answer as
2.79 molesHope this helps you
Define-Ductility, malleability, sonority, electrical conductivity, thermal conductivity
The molar enthalpy of fusion for water is 6.008 kJ/mol. How much energy is released when 4.81 mol of water freezes?
Answer: The energy released when 4.81 mol of water freezes is 28.9kJ
Explanation:
Latent heat of fusion is the amount of heat required to convert 1 mole of solid to liquid at atmospheric pressure or energy released when 1 mole of liquid freezes to solid at atmospheric pressure.
[tex]\Delta H_{fusion}[/tex] = enthalpy change for fusion = 6.008 KJ/mole
Energy released when 1 mole of water freezes = 6.008 kJ
Energy released when 4.81 moles of water freezes = [tex]\frac{6.008 kJ}{1}\times 4.81mol=28.9kJ[/tex]
Therefore, the energy released when 4.81 mol of water freezes is 28.9kJ
I am lost someone help me!!
Try tissue
Explanation:
how much does carbon cost?
Answer:
50 pero tom so 50 dollares
Activity
solve the problems below to practice what you have learned. Remember to use the formula for a heat transferred: Q=mC(T: - T:).
Part A
The specific heat of lead is 0.129 yg°C. Find the amount of heat transferred to lead when 355 grams are heated from 95°C to 140°C.
BIŲ x
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Answer:
2060.775 J
Explanation:
From the question given above, we obtained the following data:
Specific heat capacity (C) = 0.129 J/g°C
Mass (m) = 355 g
Initial temperature (Tᵢ) = 95 °C
Final temperature (Tբ) = 140 °C
Heat (Q) tranfered =?
We can calculate the amount of heat transferred by using the following formula:
Q = mC(Tբ – Tᵢ)
Q = 355 × 0.129 (140 – 95)
Q = 45.795 × 45
Q = 2060.775 J
Thus, 2060.775 J of energy was transferred.
Answer:
2060.775 Joules
Explanation:
The mass of radium-226 in a sample is found to have decreased from 45.00g to 5.625g in a period of 4800 years.From this information. Calculate the half life of radium-226
Answer:
Half life = 1600 years
Explanation:
Given data:
Total mass of sample = 45.00 g
Mass remain = 5.625 g
Time period = 4800 years
Half life of radium-226 = ?
Solution:
First of all we will calculate the number of half lives passes,
At time zero 45.00 g
At first half life = 45.00 g/ 2= 22.5 g
At 2nd half life = 22.5 g/ 2 = 11.25 g
At 3rd half life = 11.25 g/ 2= 5.625 g
Half life:
Half life = Time elapsed / number of half lives
Half life = 4800 years / 3
Half life = 1600 years
How many neutrons does the isotope have?
Answer:
16 neutrons.
Explanation:
From the question given above, the following data were obtained:
Mass number = 30
Atomic number = 14
Neutron number =?
Next, we shall determine the number of protons present in the isotope. This can be obtained as follow:
The atomic number of an element is simply defined as the number of protons present in the atom of the element. Thus,
Atomic number = Proton number
Atomic number = 14
Therefore,
Proton number = 14
Finally, we shall determine the number of neutons present in the isotope as follow:
Mass number = 30
Proton number = 14
Neutron number =?
Mass number = Proton + Neutron
30 = 14 + Neutron
Collect like terms
Neutron = 30 – 14
Neutron = 16
Therefore, the isotope contains 16 neutrons.
The element hydrogen contains particles of
OA. water and carbon.
OB. hydrogen only.
OC. hydrogen, oxygen, and nitrogen. OD. oxygen and carbon.
Please HELP!
Answer:
B. hydrogen only.
Explanation:
The element hydrogen is a made up of only hydrogen atoms which are the particles in the element.
Hydrogen is an element. It has distinct hydrogen atoms that typifies it.
Water and carbon is not a hydrogen element. They contain hydrogen, oxygen and carbon.An element is a distinct substance that is made up of one kind of atom. The only kind of atom in element hydrogen is those hydrogen itself.
A 23.7 g piece of iron at 54.9 C is cooled and releases 338 J of heat. The specific heat of iron is 0.450 J/gC. What is the final temperature of the iron?
Answer:
39
Explanation:
cux it is
Answer: 23.3 °C
Explanation: The one above is wrong
In a covalent compound like O2, two pairs of electrons are shared between the atoms. What is the name given to a bond like this?
Explanation:
The bond is a covalent bond.
1. How much heat is required to melt 25.0 g of ice at 0°C?
Answer: The heat required to melt 25.0 g of ice at [tex]0^0C[/tex] is 8350 Joules
Explanation:
Heat of Fusion tells us how much energy is needed to convert 1g of a solid to a liquid at the same temperature.
[tex]Q=m\times L[/tex]
Q = Heat absorbed = ?
m = mass of ice = 25.0 g
L = Latent heat of fusion of ice = 334 J/g
Putting in the values, we get:
[tex]Q=25.0g\times 334J/g=8350J[/tex]
Thus heat required to melt 25.0 g of ice at [tex]0^0C[/tex] is 8350 Joules
........PLEASE HELP........
if you have 30% of 100 milliliters of an aqueous solution of ethanol, what volumes of ethanol and water are in the solution?
Volumes of ethanol and water are in the solution : 30 mL and 70 ml
Further explanationThe concentration of a substance can be expressed in several quantities such as moles, percent (%) weight/volume,), molarity, molality, parts per million (ppm) or mole fraction. The concentration shows the amount of solute in a unit of the amount of solvent.
Percent Volume (% v/v) : volume (ml) of solute/100 ml of solution ⇒ ratio of volume of the solute to total volume of the solution
[tex]\tt \%solute=\dfrac{solute~volume}{solution~volume}\times 100\%[/tex].
30% ethanol ⇒30% etanol, 70% water
In 100 mL solution :
[tex]\tt Ethanol=30\%\times 100~mL=30~mL\\\\Water=70\%\times 100~mL=70~ml[/tex]
Which of the following do all food chains in an ecosystem depend on
Question 12 of 32
The work of which scientist was most essential to the use of the scientific
method and quantitative measurements in chemistry?
A. Antoine-Laurent Lavoisier
B. John Dalton
O C. Robert Boyle
O D. Marie Curie
Answer:
A. Antoine-Laurent Lavoisier
Explanation:
Hope this helped!
What pieces of evidence do scientists use to support the current theory of rapid expansion?
Answer:
When looking at the radiation emitted by distant stars or galaxies, scientists see emission spectra 'shifted' towards the red end of the electromagnetic spectrum—the observed wavelengths are longer than expected. ... Something causes the wavelength of the radiation (emitted by faraway stars and galaxies)
what are two ways that substances can pass through a cell membrane out of the cell
Answer:
Passive transport, and Active transport
Explanation:
Do u need an explanation?
If so you can tell me and I'll edit it
Hope this helped a little!
Why is an occluded front considered the most complex type of front?
Answer:
folloow mw tiktokjonathan_dion21 for a free cookie
Explanation:
what phase is skipped during sublimation
Answer:
Liquid
Explanation:
If a phase is skipped, the skipped phase will be liquid because it is the only phase between solid and gas.
Answer:
liquid
Explanation:
sublimation, is when a substance goes directly from a solid to gas. it doesn't pass through the liquid state.
If Anna mixed a juice powder and water because she will make a juice drink, she will create a _____?
She will create a solution.
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Question 13 / 40
When electrons move from a high energy level to a low energy level, which of the following statements are correct?
spectral lines are emitted
mass is converted to energy
the photoelectric effect occurs
quarks combine to create subatomic particle
Answer:
Explanation:
Mass is converted to energy
2. Which of the following is a greenhouse gas?
Answer in two or three sentences
Why do you believe knowing how elements and compounds react together is essential in everyday matters?
Answer:
Knowing how elements and compounds react together is essential in everyday life is essential to people like a scientist and someday you might become a scientist no matter what you become you will have to learn all that you can.
UwU Hope I helped
Answer:
it is very important to know how elements and compounds react together because everything that surrounds us is made out of elements and compounds. Therefore, understanding how these work can allow us to have a better understanding of the world that surrounds us. Moreover, it can avoid accidents when we deal with dangerous compounds, such as when we cook or clean
Explanation:
Which elements did the Curies discover?
A. thorium and polonium
B. radium and uranium
C. radium and polonium
D. uranium and curium
Answer:
B on edge
Explanation:
Curies discovered two new radioactive elements radium and polonium.
What becomes the first detail observed through the Curies?They first determined polonium, named for Marie's place of origin Poland, in July 1898. whilst Marie Curie become joined via her physicist husband Pierre Curie to have a look at uraninite, then known as pitchblende, a uranium-rich mineral, and ore.
What 3 matters did Marie Curie find out?Indefatigable notwithstanding a profession of bodily demanding and in the end fatal work, she located polonium and radium, championed the use of radiation in medication, and basically changed our information about radioactivity. Curie changed into born Marya Skłodowska in 1867 in Warsaw.
Learn more about radioactive elements here: https://brainly.com/question/2902625
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What is the significance of the Roman Numeral when naming binary ionic compounds?
Answer:
Roman numbers are oxidation state of the metals
Because some elements of metals show more than one oxidation state like iron Fe2+ in ferrous and Fe3+ in ferric.
Explanation:
Describe the chemical reaction based on the
chemical equation below.Also, explain whether
the equation is balanced.
NH2(g) O2(g) pt NO(g)+H2O(I)
Answer:
Ammonia gas reacts with oxygen gas.
Nitric oxide gas and liquid water are produced.
Platinum is used as a catalyst.
The equation is unbalanced because the number of hydrogen atoms is not the same on both sides of the equation.
Explanation:
7th grade science , help me please :))
Pls Help me I am stuck on this question.
Answer:
compound is the answer
According to the equation for the kinetic energy of a moving object, which gas would have the lowest average velocity, assuming all gases are at the same temperature?
Answer:
O3
Explanation:
According to the equation for the kinetic energy of a moving object, O3 (OZONE) gas would have the lowest average velocity, assuming all gases are at the same temperature.
What is Temperature?A temperature is a unit used to represent hotness or coolness on any of a number of scales, including Fahrenheit and Celsius. According to temperature, heat energy will naturally move from a hotter (body with a higher temperature) to a colder (body with a lower temperature) (one at a lower temperature)
Although these descriptive words are well-known and suitable to describe this landscape, they do not accurately convey temperature. By definition, the temperature is a technique to express warmth and coldness through numerical descriptors. To put it another way, it can provide a subjective description of a comparable, numerical value.
A thermometer is frequently used to measure temperature. The idea of thermal equilibrium must be understood in order to comprehend how thermometers function. Thermal equilibrium occurs when two materials that are in contact are both at the same temperature.
To learn more about Temperature follow the link.
https://brainly.com/question/23411503
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How much thermal energy must be added to a 87.5 g sample of ice at -25oC completely melt the entire sample? As part of your work, sketch a labelled heating curve. Circle the portion of the curve that is the focus of this question.
Answer:
4.6 kJ
Explanation:
The energy required to raise the temperature of a substance from its initial temperature to a final temperature is given by:
Q = mcΔT
Where Q = energy, c = specific heat capacity of substance and ΔT = final temperature - initial temperature
Given that:
c = 2.1 kJ/kg°C, m = 87.5 = 0.0875 kg, ΔT = final temperature - initial temperature = 0 - (-25) = 25
Q = 0.0875 * 2.1 *25
Q = 4.6 kJ