What is the mass number of an element?
how many atoms are in 4.5 moles of Al?
Explanation:
4.5×6.022×10²³
27.099×10²³
According to Avogadro's number, there are 27.10×10²³ atoms in 4.5 moles of Al.
What is Avogadro's number?Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.
It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .
According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.
Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number.As 1 mole =6.023×10²³ atoms , thus,4.5 moles =4.5×6.023×10²³ = 27.10×10²³ atoms.
Thus, there are 27.10×10²³ atoms in 4.5 moles of Al.
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5. What is the difference between a reflected and a diffracted sound wave?
A. A reflected sound wave is absorbed by the medium. A diffracted sound wave changes
direction as it passes through an opening.
B. A diffracted sound wave bounces back to the place of origin. A reflected sound wave is
absorbed as it passes through an opening.
C. A reflected sound wave bounces back to the place of origin. A diffracted sound wave
changes direction as it passes through an opening.
D. A diffracted sound wave bounces back to the place of origin. A reflected sound wave
changes direction as it passes through an opening.
Answer:
Reflection involves a change in direction of waves when they bounce off a barrier; refraction of waves involves a change in the direction of waves as they pass from one medium to another; and diffraction involves a change in direction of waves as they pass through an opening or around a barrier in their path.
Explanation:
https://www.physicsclassroom.com/class/waves/Lesson-3/Reflection,-Refraction,-and-Diffraction#:~:text=Diffraction%20of%20Waves-,Reflection%20involves%20a%20change%20in%20direction%20of%20waves%20when%20they,a%20barrier%20in%20their%20path.
Reflection of sound wave differs from diffraction of sound wave in that a reflected sound wave bounces back to the place of origin while a diffracted sound wave changes direction as it passes through an opening.
What is reflection?Reflection is the bouncing back of a wave when it hits an obstacle along its path.
What is diffraction?Diffraction is the spreading out of a wave in a circular path as it passes through a tiny opening.
Therefore, the difference between reflection and diffraction is that a reflected sound wave bounces back to the place of origin while a diffracted sound wave changes direction as it passes through an opening.
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what is:
Na2O+SO2 =
for chemistry
Na2SO3 – Sodium sulfite
Which of the following would be the best caption for this image?
A
The Coriolis effect causes convection cells of air to circulate through the atmosphere.
B
The pattern of ocean currents is identical to the pattern of wind currents.
C
Uneven heating of land and water causes winds to blow in different directions during the daytime and night time.
D
There are six bands of global wind currents. These bands of wind currents are caused by convection cells created by the warming and cooling of air.
Which of the following elements has the ability to undergo sublimation
iodine
oxygen
carbon sodium
Answer:
iodine
Explanation:
Ionic compounds are held together with ionic bonds between ions. The ions are formed when valence electrons are
Answer: Electrovalent bonds are produced when electrons are transferred from atoms of one element to atoms of another element, producing positive and negative ions. The bond which is formed by the transfer of electrons between the atoms is called electrovalent bond or ionic bond. Electrovalent bonds are only formed between metals and non-metals. Electrovalent bonds are not formed between two non-metals.
In simple words electrovalent bond involves the transference of a certain number of electrons to another dissimilar atom which has a tendency to gain electrons so that both acquire stable inert gas configurations. The electrostatic attraction always tends to decrease the potential energy. Hence, the potential energy of the system is much less than it was before the formation of an ionic bond.
Explanation: An Ionic bond is the bond formed by the complete transfer of valence electron to attain stability.
This type of bonding leads to the formation of two oppositely charged ions – positive ion known as cations and negative ions are known as anions.
The presence of two oppositely charged ions results in a strong attractive force between them. This force is an ionic or electrovalent bond.
Ionic bonds form between atoms with large differences in electronegativity, whereas covalent bonds formed between atoms with smaller differences in electronegativity.
The compound formed by the electrostatic attraction of positive and negative ions is called an ionic compound.
Help please help me!!!!!
Answer:
B. 460 NM
Explanation:
THAT THE ANSWER
Question 21 of 25
Which of the following are elements in this equation:
2Mg(s) + O2 (9) ► 2Mgo (s)?
Check all that apply.
A. g
B. Mg
C. O
D. S
Answer: Mg and O
Explanation: just took the test. Trust
please helpppp!!!!!!!!!!!
Answer:
If a substance can be dissolved it is called soluble.
if a substance cannot be dissolved it is called insoluble
I need help on deciding which one i should get
Answer:
I would say the purple one!
Explanation:
Which of the following statements are true? Select all that apply. Check All That Apply All isotopes of carbon (C) have the same number of protons. All isotopes of carbon (C) have the same number of protons. An atom with six protons in its nucleus will always have six neutrons in its nucleus. An atom with six protons in its nucleus will always have six neutrons in its nucleus. An atom with a neutral charge has an equal number of protons and electrons.An atom with a neutral charge has an equal number of protons and electrons. The mass number is the total number of electrons and protons in an atom. The mass number is the total number of electrons and protons in an atom.
Answer:
An atom with a neutral charge has an equal number of protons and electrons.
Explanation:
The three main subatomic particles in the atom are neutrons, protons and electrons.
Protons are positively charged particles, electrons are negatively charged particles while neutrons are not charged particles.
An atom is neutral if the number of protons and electrons are equal. This is the condition for neutrality in the atom.
The number of protons will be the same for all isotopes of Carbon. Options A and C are correct.
What made an atom?
An atom is made up of central nucleons (positive protons and neutral neutrons) and surrounding negatively charged electrons.
In a neutral atom, the number of electrons and protons is the same because opposite charges neutralize each other.
The number of protons is the same in all isotopes of an element because changing the proton changes the identity of the element.
Therefore, the number of protons will be the same for all isotopes of Carbon.
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why do we need to rinse the mouth before collecting the saliva
A gas has a volume of 45.0 mL and a pressure of .98 atm. If the pressure increased to 2.1 atm and the temperature remained the same, what would be the new volume?
Answer: The new volume is 95.45 mL.
Explanation:
Given: [tex]V_{1}[/tex] = 45.0 mL, [tex]P_{1}[/tex] = 0.98 atm
[tex]P_{2}[/tex] = 2.1 atm, [tex]V_{2}[/tex] = ?
According to Boyle's law, at constant temperature the pressure of a gas is inversely proportional to its volume.
Therefore, formula used to calculate the new volume is as follows.
[tex]\frac{P_{1}}{V_{1}} = \frac{P_{2}}{V_{2}}[/tex]
Substitute the values into above formula as follows.
[tex]\frac{P_{1}}{V_{1}} = \frac{P_{2}}{V_{2}}\\\frac{0.98 atm}{45.0 mL} = \frac{2.1 atm}{V_{2}}\\V_{2} = 95.45 mL[/tex]
Thus, we can conclude that the new volume is 95.45 mL.
Based on information from the periodic table, which statement is true for the
element cobalt?
Answer: (A) a cobalt atom contains 27 protons, and most cobalt atoms contain 32 neutrons.
Explanation: just answered the question and that was the correct answer
Answer: The answer is : A cobalt atom contains 27 protons and MOST neutral cobalt atoms contain 32 electrons
Explanation: I took the test
Why does the earth rotate
A:because it’s formed from cold gases collapsing due to gravity
B: Because the matter in the nebula that formed
C:Because the earth form is more than 99% of the mass of the Solar system
D; Because the hydrogen Adams inside the nebular fuse to form helium
Answer:
A
Explanation:
Your answer would be A because Earth is formed from cold gases collapsing due to gravity. The Solar System was formed when a huge amount of dust and gas began to collapse under its own gravity, and as the cloud collapse it started to spin causing the material within the cloud to gather into a swirl and then formed into planets and as the planets are formed they kept this spinning motion.
classify the following alcohols as primary secondary and tertiary alcohols?
Which of the following statements describes a REACTANT and where they are
chemical equation?
The chemicals that
you begin with, found
on the right side of the
equation
The chemicals that The chemicals that The chemicals that
you begin with, found end with, found on the you enyi with, found or
on the left side of the left side of the the right side of the
equation
equation
equation
Music of
Answer: The statement, chemicals that you begin with found on the left side of the equation, describes reactant and where they are in a chemical equation.
Explanation:
An equation that includes symbolic formulas and represents chemical reaction between the substances initially present forming new substances is called a chemical equation.
For example, [tex]N_{2} + 3H_{2} \rightarrow 2NH_{3}[/tex]
Here, substances [tex]N_{2}[/tex] and [tex]H_{2}[/tex] are the reactants. Reactants in a chemical equation are always present on the left side as these are the chemicals we begin with.
Also here, [tex]NH_{3}[/tex] is the product. Product(s) in a chemical equation are always present on the right side as these are the chemicals we end with.
Thus, we can conclude that the statement, chemicals that you begin with found on the left side of the equation, describes reactant and where they are in a chemical equation.
During Photosynthesis, what does a producer take in from the air?
Drag the slider from January to December. Based on what you observe, do you think Barcelona has large temperature changes throughout the year?
Answer:
Yes.
Explanation:
Yes, I think that Barcelona has large temperature changes throughout the year because Barcelona has minimum temperature of 33°F in winter season and maximum temperature of 88°F in summer season. In Barcelona, the summers are short, warm, and humid while on the other hand, the winters in Barcelona are long, cold, and partly cloudy. The temperature typically varies from 40°F to 83°F and is rarely goes below 33°F or above 88°F.
What is a state function?
How many moles of aluminum are in 54 grams
Using the example of an ambulance, explain the Doppler Effect. Infer why the doppler effect can or cannot occur in all waves. PLEASE ANSWER ILL PICK BRAINLEIST TO THE FIRST ACTUAL ANSWER
Answer:
When the ambulance is coming towardss you the waves are smushed together and sound higher pitched but then it passes you and when tracveling away the waves are scretched out so the whee whoo sounds lower and that is because of the doppler effect
5). At what temperature (K) will 0.854 moles of neon gas occupy 12.3 L at 1.95
atmospheres?
Answer:
338.38 K
Explanation:
Applying,
PV = nRT............... Equation 1
Where P = pressure, V = Volume, R = Temperature, n = number of moles, T = temperature.
Make T the subject of the equation,
T = PV/nR............. Equation 2
From the question,
Given: P = 1.95 atm, V = 12.3 L, n = 0.854 moles
Constant: R = 0.083 L.atm/K.mol
Substitute these values into equation 2
T = (1.95×12.3)/(0.854×0.083)
T = 338.38 K
If a solution has a [H+] of 9.3x10-11, what is the pH?
Answer:
10.03Explanation:
The pH of a solution can be found by using the formula
[tex]pH = - log [ {H}^{+} ][/tex]
From the question we have
[tex]ph = - log(9.3 \times {10}^{ - 11} ) \\ = 10.0315...[/tex]
We have the final answer as
10.03Hope this helps you
-
(11) Deduce the number of dyes in food colouring H.
(iii) Suggest why food colouring F does not move during the experiment.
(iv) Explain which two food colourings contain the dye that is likely to be the most soluble the solvent.
(b) Determine which food colouring contains a dye with R, value closest to 0.67
Show your working.
Answer:
(ii) 1 dye
(iii) Food coloring F is insoluble in the solvent
(iv) 'E' and 'H'
(b) Food colouring G
Explanation:
Paper chromatography principle is based on the rates of migration of chemicals across a sheet of paper which are different and it consists of a stationary phase such as the water in the paper and a mobile phase such as the solvent resulting in the partitioning of the components of the mixture across the paper
The solution components are positioned to start in one place from where they migrate and separate out on the chromatography paper
(ii) The number of components into which the food colouring 'H' separates into = 1
Therefore, the number of dyes in food colouring 'H' = 1 dye
(iii) Food coloring 'F' does not move because it is insoluble in the solvent, which is the mobile phase
(iv) The food colouring that contains the dye that is likely to be most soluble in the solvent are does for which the dyes travel furthest, which are;
Food coloring 'E' and 'H'
(b) Using a similar question solution found on 'tutor my self' website, we have;
The [tex]R_f[/tex] values are given as follows;
[tex]R_f = \dfrac{Distance \ moved \ by \ dye}{Distance \ moved \ by \ solvent}[/tex]
The distance moved by the solvent = 5 units
The distance moved by dyes in food colouring 'E' and 'H' = 4 units
The distance moved by dye in food colouring 'G' = 3.3 units
The distance moved by the second dye in food colouring 'E' = 2.7 units
By inspection, we get;
[tex]R_f[/tex] dye in food colouring 'G' = 3.3/5 = 0.66,
Therefore, the dye with [tex]R_f[/tex] value closest to 0.67 is the dye in food colouring 'G'.
what do mars, pluto, and Jupiter have in common (science) in 8th grade.
Answer:
they are all planets
Explanation:
Balance the equation ___C+___Fe203—-____CO2+___Fe
Answer:
3,2,3,4
Explanation:
try this answer, it's syits best to the question
How many liters of a 6.0 M solution of acetic acid contain 0.0030 moles
Answer: Least Common Multiplier of a6m, 0.003 moles 0.01elamos
Steps 6m, 0.003 moles
Compute an expression comprised of Factors that appear either in a6m or 0.003 moles
= 0.018elamos
Explanation:
Taking into account the definition of molarity, 0.005 liters of a 6.0 M solution of acetic acid contain 0.0030 moles.
Definition of molarityMolar concentration or molarity is a measure of the concentration of a solute in a solution and indicates the number of moles of solute that are dissolved in a given volume.
The molarity of a solution is calculated by dividing the moles of solute by the volume of the solution:
[tex]molarity=\frac{number of moles}{volume} [/tex]
Molarity is expressed in units [tex]\frac{moles}{liters} [/tex].
This caseIn this case, you have a 6.0 M solution of acetic acid that contain 0.0030 moles. Replacing in the definition of molarity:
[tex]0.6\frac{moles}{liters} =\frac{0.0030 moles}{volume} [/tex]
Solving:
0.6 [tex]\frac{moles}{liters} [/tex]× volume= 0.0030 moles
volume= 0.0030 moles ÷0.6 [tex]\frac{moles}{liters} [/tex]
volume=0.005 liters
Finally, 0.005 liters of a 6.0 M solution of acetic acid contain 0.0030 moles.
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What is the pressure of a car tire that had an initial pressure of 33.7 kPa but was
heated from 98.4°C to 110.°C?
Answer:
34752.6 Pa.
Explanation:
Applying,
P/T = P'/T'............... Equation 1
Where P = Initial Pressure, T = Initial Temperature, P' = Final pressure, T' = Final temperature.
make P' the subject of the equation
P' = (PT'/T).............. Equation 2
From the question,
Given: P = 33.7 kPa = 33700 Pa, T = 98.4°C = (273+98.4) = 371.4 K, T' = (110+273) = 383 K
Substitute these values into equation 2
P' = (33700×383)/371.4
P' = 34752.6 Pa.