Answer:
Mass number
Nucleus
Explanation:
The combined number of protons and neutrons is the mass number in atomic notation.
The atomic number is just the number of protons alone.
The nucleus holds both neutrons and protons.
Electrons circle around the nucleus.
Answer: atomic mass I did it
Explanation:
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Answer:
0.333333 cal/g-°C
Explanation:
Energy = mass x specific heat capacity x temperature change.
(E = mcΔT)
Energy = 100.0 cal
specific heat capacity c= unknown
mass m = 4.0 g
temperature change ΔT = 100 - 25 =75°
100 = 4c(75)
c = 0.333333 cal/g-°C
Which Group has different numbers of valence electrons?
A. Alkaline earth metals
B. Alkali metals
C. Transition metals
D. Halogens
Answer:
[tex]c. \: transition \: metals[/tex]Transition metals (Group C) have different numbers of valence electrons compared to the other groups mentioned. Therefore option C is correct.
Transition metals (Group 3-12) have varying numbers of valence electrons. This is because their valence electrons are located in more than one energy level or subshell.
The number of valence electrons for transition metals can range from 1 to 12, depending on the specific element within the group. The varying numbers of valence electrons in transition metals contribute to their diverse chemical properties and ability to form multiple oxidation states.
Therefore, transition metals (Group C) have different numbers of valence electrons compared to the other groups mentioned.
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MARKING BRAINLIEST!! - Determine the molar mass [MM] of a gas if 2 L of the gas weights 0.500 g at 298 K and 2.00 atm.
Answer:
3.125g/mol
Explanation:
To find the molar mass of the gas, we need to initially find the number of moles (n) contained in the gas. To find the number of moles, we use the general gas law whose equation is:
PV=nRT
Where; P= Pressure
V= Volume occupied by gas
n= number of moles
R= general gas constant
(0.0821 L atm mol/K)
T= absolute temperature
According to the question; P= 2.0atm, V= 2.0L, n= ?, T= 298K
To find n, we make it the subject of the formula:
n= PV/RT
n= 2.0 × 2.0 / 0.0821 × 298
n= 4/ 24.4658
n= 0.16mol
If number of moles (n) of the gas is 0.16mol and it weighs 0.500g, its molar mass can be found using:
number of moles (n) = mass (g) / molar mass
Making MM subject of the formula;
molar mass = mass / number of moles
MM= 0.500/0.16
MM= 3.125
Hence, the molar mass of the gas is 3.125g/mol.
When Niels Bohr refined the model of an atom,what new idea did he include?
Answer:
Niels Bohr, refined the model of an atom by proposing a quantized shell structure atomic model in order to describe how the electrons are able to maintain stable orbits around the nucleus
Based on the predictions of classical mechanics the electron motion of the Rutherford model was unstable as the electrons where expected to have lost some energy during motion and thus having to come rest in the nucleus
According to the modification by Neils Bohr in 1913, electrons move in shells or orbits of fixed energy and emission of electromagnetic radiation takes place only when electrons changes the orbit in which they move
Explanation:
When the name of ions end with ide, is it true that they are all negative ions
Magnesium unites completely and vigorously with oxygen to form magnesium oxide, which contains 60% magnesium by weight. If 1.00 gram of magnesium is sealed in a glass tube with 1.00 gram of oxygen, what will be present in the tube after the reaction has taken place
Answer:
After the reaction, there will 0.60 g of magnesium oxide and 0.25 g of oxygen gas present in the tube
Explanation:
Equation of the reaction between magnesium and oxygen is given as follows:
2Mg(s) + O₂(g) ---> 2MgO(s)
From the equation of reaction, 2 moles of magnesium reacts with i mole of oxygen gas to produce 1 mole of magnesium oxide
molar mass of magnesium is 24.0 g; molar mass of oxygen gas = 32.0 g; molar mass of magnesium oxide = 40.0 g
Therefore 24 g of magnesium reacts with 32 g of oxygen gas
I.00 g of magnesium will react with (24.0 / 32.0) * 1.00 g of oxygen = 0.75 g of oxygen gas.
Therefore, magnesium is the limiting reagent. Once it is used up, the reaction will stop and the excess oxygen will be left in the tube together with the product, magnesium oxide.
mass of excess oxygen = 1.00 - 0.75 = 0.25 g
mass of magnesium oxide formed = (24.0 / 40.0 g) * 1 = 0.60 g
what is the difference between the atom and isotope
Answer:
Atoms consist of a nucleus made of protons and neutrons orbited by electrons.
Isotopes are atoms that have same number of protons but they differ in the number of neutrons and in atomic mass.
Answer:
Isotopes are atoms that have the same numbers of protons but different numbers of neutrons. An ion is an atom that has gained or lost electrons, so it now has more or fewer electrons than it does protons. So an ion has a negative or positive charge.
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Molar mass of Al(OH)3 =
Answer:
78.01 g/mol
Explanation:
To find the molar mass of Al(OH)₃, we have to look at the mass of each individual element on the periodic table.
Al - 26.98
O - 3(16.00) = 48.00
H - 3(1.01) = 3.03
Now add it all together.
26.98 + 48.00 + 3.03 = 78.01 or 78 g/mol
Hope that helps.
What are chemical changes of matter?
Answer:
Chemical Changes are also called Chemical Reactions. Chemical reactions involve combining different substances. The chemical reaction produces a new substance with new and different physical and chemical properties. Matter is never destroyed or created in chemical reactions.
Explanation:
What would be the charge on an ion whose neutral atom has an electron configuration of 2.8.7?
O A. +7
OBO
C. +1
Answer:
–1
Explanation:
The electronic configuration of the neutral atom is given below:
2 8 7
From the electronic configuration of the neutral atom, we can see that the atom has 7 electrons in it's outermost shell. This implies that the element needs 1 more electron to complete it's octet configuration.
Therefore the charge on the ion of the element will be –1 indicating that the atom has received 1 electron to complete it's octet configuration.
Based on the information that is given, which atom in the table has the highest mass?
The question is incomplete, the complete question is;
Atom Number of protons Number of electrons Number of neutrons
1 39 39 52
2 40 40 50
3 39 39 54
4 40 40 51
Based on the information that is given, which atom in the table has the highest mass?
a. 1
b. 2
c. 3
d. 4
Answer:
c
Explanation:
The relative atomic mass is given as; number of protons + number of neutrons. If we take the relative atomic mass of each of the options;
1) 39 +52 = 91
2) 40+50 = 90
3) 39 + 54 = 93
4) 40 + 51 = 91
Thus 3 has the highest mass as seen above, hence the answer given.
Q2.
For the reaction given, how many litres of carbon dioxide gas will be formed by the reaction of 400
litres of oxygen with sufficient pentene (CH..)? The reaction takes place at 125°C and 10.5 atm.
2 C5H10(1) + 15 O2(g) →10 CO2(g) + 10 H20 (8)
Answer:
266 liters Carbon iv oxide will be formed
Explanation:
The first thing we need to do here is to calculate the number of moles of oxygen reacted.
This can be calculated using the ideal gas equation;
Mathematically;
PV = nRT
From the question;
P = pressure = 10.5 atm
V = volume = 400 liters
n = number of moles = ?
T = temperature = 125 + 273 = 398K
R = molar gas constant = 0.0821 L•atm•K^-1•mol^-1
Substituting these values, we have ;
n = PV/RT
n = (10.25 * 400)/(398 * 0.0821) = 125 moles
From the question;
15 moles oxygen gave 10 moles CO2
125 moles oxygen will give x moles CO2
x = (125 * 10)/15 = 83 moles
Now, we want to know the volume of CO2, present in 83 moles using the given reaction conditions.
Mathematically;
PV = nRT
V = nRT/P
= (83 * 0.0821 * 398)/10.25 = 265.65 which is approximately 266 Liters
The reaction below was carried out in an acidic solution. Upper I minus, plus upper I upper O minus subscript 3 right arrow upper I subscript 2. Which statement is true about this equation?
Answer:
It has been balanced by using the half-reaction method.
Explanation:
I- and IO3- gives I2
We divide the reaction into two half-reactions
(2 I- >> I2 + 2e-) x5 ( oxidation : I goes from -1 to 0 )
2 IO3- + 12H+ + 10e- >> I2 + 6H2O ( reduction : I goes from +5 to 0 )
10 I- >> 5I2 + 10e-
2IO3- + 12H+ + 10e- >> I2 + 6H2O
-----------------------------------------------------
10 I- + 2IO3- + 12H+ >> 6I2 + 6H2O
To get the smallest numbers we divide by 2 :
5 I- + IO3- + 6H+ >> 3I2 + 3H2O
It has been balanced by using the half-reaction method. Hence, option B is correct.
What is a redox reaction?A chemical reaction that takes place between an oxidizing substance and a reducing substance.
We divide the reaction into two half-reactions
[tex](2 I^-[/tex] → [tex]I_2 + 2e^-)[/tex] x 5 ( oxidation : I goes from -1 to 0 )
[tex]2 IO^{3-} + 12H^+ + 10e^-[/tex] → [tex]I_2 + 6H_2O[/tex] ( reduction : I goes from +5 to 0 )
[tex]10 I^-[/tex] →[tex]5I_2 + 10e^-[/tex]
[tex]2IO^{3-} + 12H^+ + 10e^-[/tex] → [tex]I_2 + 6H_2O[/tex]
[tex]10 I^- + 2IO^{3-} + 12H^{+}[/tex]→ [tex]6I_2 + 6H_2O[/tex]
To get the smallest numbers we divide by 2 :
[tex]5 I^- + IO^{3-} + 6H^+[/tex] → [tex]3I_2 + 3H_2O[/tex]
Hence, option B is correct.
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Escribe verdad o falso: La clorofila capta la energía luminosa del sol. () La fotosíntesis degrada las sustancias orgánicas que nesecitas las células()
Answer:
La clorofila capta la energía luminosa del sol. (verdadero) La fotosíntesis degrada las sustancias orgánicas que nesecitas las células(falso)
Explanation:
La clorofila es la encargada de dar el pigmento de color verde en las plantas y la que transforma la energia luminica en energia quimica, es por eso que es verdadera.
La fotosintesis NO degrada las sustancias organicas, sino que transforma un sustrato inorganico en una fuente energetica organica para las plantas.
Esto se debe por que las plantas o vegetales son autonomas, es decir que se autoabastecen energeticamente sin necesidad de ingerir alimentos como en el caso de los mamiferos.
What is the solute in the mixture of muddy water
Answer:
A solute is a solid which dissolves in a solvent. Muddy water contains water and soil, soil does not dissolve in water
How many atoms are in 10g of Al
Answer:
The correct answer is
Explanation:
hope this helps u!!
If 50.0cm3of a saturated solution of KNO3at 40oC contained 5.05g of the salt. What is the solubility of the salt at 40oC? [KNO3=101].
Answer:
The solubility of KNO₃ at 40° C is 1 mol/dm³
Explanation:
The solubility of a substance is the number of moles of that substance (solute) contained in a unit volume of solvent at that particular temperature.
Now, Solubility = n/V where n = number of moles of KNO₃ and V = volume of saturated solution = 50.0 cm³ = 0.05 dm³
n = m/M where m = mass of KNO₃ = 5.05 g and M = molar mass of KNO₃ = 101 g/mol
n = 5.05 g/101 g/mol = 0.05 mol
Solubility = n/V
= 0.05 mol/0.05 dm³
= 1 mol/dm³
So, the solubility of KNO₃ at 40° C is 1 mol/dm³
Give one reason why water gas and producer gas are prepared together in the same furnace. Pls ansa its urgent
Answer:
because water gas has high heat content more than producer gas
Explanation:
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Define the term “Tyndall effect”. Which of the following would show Tyndall effect:- (Starch solution, sodium chloride solution, alcohol and water mixture)
Answer:
Tyndall Effect is the phenomenon of scattering of light by particles in a colloid or in a very fine suspension.
Starch solution would show Tyndall effect.
N/B: Heterogeneous mixtures show Tyndall effect.
Answer:The Tyndall effect is light scattering by particles in a colloid or in a very fine suspension. Also known as Willis–Tyndall scattering, it is similar to Rayleigh scattering, in that the intensity of the scattered light is inversely proportional to the fourth power of the wavelength, so blue light is scattered much more strongly than red light. An example in everyday life is the blue colour sometimes seen in the smoke emitted by motorcycles, in particular two-stroke machines where the burnt engine oil provides these particles.
Under the Tyndall effect, the longer wavelengths are more transmitted while the shorter wavelengths are more diffusely reflected via scattering. The Tyndall effect is seen when light-scattering particulate matter is dispersed in an otherwise light-transmitting medium, when the diameter of an individual particle is the range of roughly between 40 and 900 nm, i.e. somewhat below or near the wavelengths of visible light (400–750 nm).
It is particularly applicable to colloidal mixtures and fine suspensions; for example, the Tyndall effect is used in nephelometers to determine the size and density of particles in aerosols and other colloidal matter (see ultramicroscope and turbidimeter).
It is named after the 19th-century physicist John Tyndall.
Explanation:
What percentage of the total incoming radiation to the Earth reaches the ground? 20 30 40 70
Answer: 22.5 percent of incoming solar radiation goes directly to the surface of the Earth and is absorbed.
Explanation: Transfer of radiation through a planet's atmosphere. A planet and its atmosphere, in our solar system, can radiate back to space only as much energy as it absorbs from incoming solar radiation.
Answer:
Explanation:
I have the notes
"Only about 40 percent actually reaches the surface of the earth"
"our atmosphere and clouds reflect bout 40 percent of incoming solar radiation back into outer space"
"The remaining 60 percent is responsible for warming the earth"
"About 20 percent of this radiation is absorbed directly by the atmosphere"
HELPSS!
Isopropyl alcohol has a density of 0.785g/ml at 25°C. How much is contained in a 150ml sample of this alcohol?
Answer:
The amount of isopropyl alcohol contained in 150 ml of the solution is 117.15 grams
Explanation:
The density of a substance is the mass per unit volume, therefore, we have;
The density of the isopropyl alcohol = 0.785 g/ml at 25°C
The density = mass/volume
Mass = Density × Volume
The mass of the 150 ml of isopropyl alcohol is therefore;
Mass = 0.785 g/ml × 150 ml = 117.15 g
The amount in grams contained in 150 ml of sample = 117.15 g.
For reaction: 2 C + O2 --> 2 CO2 If 5.50 g C was reacted with enough O2, what would be the volume (in liter) of the CO2 generated at STP? (0 C and 1 atm)
Answer:
10.2 L of CO₂
Explanation:
Our reaction is:
2C + O₂ → 2CO₂
We convert the mass of C, to moles:
5.50 g / 12g/mol = 0.458 moles
Ratio is 2:2, so if 2 moles of C can produce 2 moles of CO₂ then 0.458 moles of C would produce 0.458 moles of gas.
By the Ideal Gases Law, we know that 1 mol of gas is contained in 22.4L, so:
0.458 mol . 22.4L / 1mol = 10.2 L
In an experiment, 125ml of H2 is collected over water at 27C and barometric pressure of 753 torr. the vapor pressure of water at 27C is 26.74 what is the partial pressure of H2?
Answer:
Partial pressure of H₂ = 0.9556 atm
Explanation:
Given:
Barometric pressure = 753 torr
Vapor pressure of water = 26.74 torr
FInd:
Partial pressure of H₂
Computation:
Partial pressure of H₂ = Barometric pressure - Vapor pressure of water
Partial pressure of H₂ = 733 - 26.74
Partial pressure of H₂ = 726.26 torr
1 atm = 760 torr
So,
Partial pressure of H₂ = 726.26/760
Partial pressure of H₂ = 0.9556 atm
What is meant by 1m length
Answer:
The metre is defined as the length of the path travelled by light in a vacuum in 1/299 792 458 of a second.
Which of the following would NOT be a conversion factor for mole to mole calculations for the following reaction: 2Al + 3Cl2 --> 2AlCl3
A: 3 mol Cl2 3 mol Al
B: 2 mol Al 3 mol Cl2
C: 2 mol AlCl3 2 mol Al
D: 3 mole Cl2 2 mol AlCl3
Answer: A. 3 mol [tex]Cl_2[/tex] 3 mol Al:
Explanation:
Te given balanced chemical equation is :
[tex]2Al+3Cl_2\rightarrow 2AlCl_3[/tex]
According to the stochiometry :
A: 3 mol [tex]Cl_2[/tex] 3 mol Al:
3 moles of chlorine reacts with 2 moles of aluminium
B. 2 mol [tex]Al[/tex] 3 mol [tex]Cl_2[/tex]:
2 moles of aluminium reacts with 3 moles of chlorine
C. 2 mol [tex]AlCl_3[/tex] 2 mol Al
2 mol of aluminium produces 2 mol of [tex]AlCl_3[/tex]
D. 3 mol [tex]Cl_2[/tex] 2 mol [tex]AlCl_3[/tex]
3 moles of chlorine produces with 2 moles of [tex]AlCl_3[/tex]
Thus the conversion factor not used for mole to mole calculations is 3 mol [tex]Cl_2[/tex] 3 mol Al:
What is the electron configuration of chlorine (Cl)?
1s22s22p63s23p3
1s22s22p63s23p5
1s22s22p63s24s23p3
1s22s22p63s23p23d3
Answer:
b) 1s22s22p63s23p5
Explanation:
Answer:
b) 1s22s22p63s23p5
Explanation:
edge 2021
a 2.000-g sample of a hydrated copper sulfate is heated and the waters of hydration are removed if that mass of the remaining salt is 1.278 g what was the percentage of water in the original hydrate
Answer:
36.1%
Explanation:
The following data were obtained from the question:
Mass of hydrated copper sulfate = 2 g
Mass of anhydrous copper sulfate = 1.278 g
Percentage of water =..?
Next, we shall determine the mass of water in the hydrated copper sulfate.
This can be obtained as follow:
Mass of hydrated copper sulfate = 2 g
Mass of anhydrous copper sulfate = 1.278 g
Mass of water =...?
Mass of water = Mass of hydrated copper sulfate – Mass of anhydrous copper sulfate
Mass of water = 2 – 1.278
Mass of water = 0.722 g
Finally, we can obtain the percentage of water in the hydrated copper sulfate as follow:
Mass of water = 0.722 g
Mass of hydrated copper sulfate = 2 g
Percentage of water =..?
Percentage of water = mass of water /mass of hydrate x 100
Percentage of water = 0.722/2 x 100
Percentage of water = 36.1%
Therefore, the percentage of water in the hydrated copper sulfate is 36.1%
An isotope of lead can be represented by the following symbol ²⁰⁷ 82 PB. From this symbol, it can be deduced that one atom of the isotope has: A) 82 neutrons B) 82 protons C) 125 protons D) 207 protons
Answer:
B) 82 protons
Explanation:
The number of protons for an element never change. 82 Is the atomic number for Pb which is how many protons it has. An isotope means it has more neutrons.
------------neutral particles in an atom
Answer:
neutrons :
Explanation:
Protons are positively charged, while electrons are negatively charged. Neutrons are electrically neutral, as the name suggests. The electric charge, noted Q , is a physical quantity.
what does a metreologist study
Answer:
A meteorologist studies meteorology which is the study of the atmosphere in order to predict/forecast the weather.
Explanation:
I hope this helps.
Answer:
they study the atmosphere and atmospheric events of our weather
Explanation: