Answer:
Physical change occur when objects or sub undergo a change that does not change their chemical composition.
Chemical change us a permanent change which occur when a substance combined with another to form a new substances.
The diagram above represents the melting of H2O(s). A 2.00mole sample of H2O(s) at 0°C melted, producing H2O(l) at 0°C. Based on the diagram, which of the following best describes the amount of heat required for this process and the changes that took place at the molecular level?
Heat : 12 kJ, to maintain hydrogen bonds
Further explanationGiven
A 2.00mole sample ⇒ n = 2 mol
H₂O(s) at 0°C melted, producing H₂O(l) at 0°C
Required
the amount of heat required
the changes that took place
Analysis
Conversion of mol to mass
Use formula of Heat :
Q = mLf (melting/freezing)
Lf=latent heat of fusion (for water=334 J/g)
Solution
mass H₂O(MW=18 g/mol) :
[tex]\tt mass=2\times 18=36~g[/tex]
Heat required :
[tex]\tt Q=36\times 334=12024~J\approx 12~kJ[/tex]
The absorbed heat is used to maintain hydrogen bonds in water molecules (there are two hydrogen bonds per molecule)
Paraphrase
The amount of heat required : 12 kJ, and to maintain hydrogen bonds
With all his gear, Neil Armstrong weighed 360 pounds on Earth. When he landed on the Moon, he weighed 60 pounds. Why?
FOR 50 POINTS & A BRAINIST*
1.) For an atom of sulfur, there are
A.) two electron shells with 6 valence electrons
B.) three electron shells with 6 valence electrons
C.) four electron shells with 6 valence electrons
D.) five electron shells with 6 valence electrons
2.) Which atom has four electron shells with 7 valence electrons?
A.) F
B.) CI
C.) Br
D.) I
3.) Which atom has three electron shells with 8 electrons in its outermost orbit?
A.) He
B.) Ne
C.) Ar
D.) Kr
4.) Which method should be used to draw electrons that are involved in a collision during a chemical reaction?
A.) Bohr's model
B.) Lewis dot model
C.) Addition model
D.) Subtraction model
Answer:
1. B
2. C
3. C
4. B
Explanation:
1. An atom of sulfur has an atomic number of 16. It has three electron shells and six valence electrons, therefore, it belongs to period 3, group VIA of the periodic table
2. Bromine has an atomic number of 35. It belongs to period 4 group VIIA of the periodic table. Therefore, it has four electron shells and seven valence electrons.
3. Argon has an atomic number of 18. It belongs to period 3, group IVA of the periodic table. Therefore, it has three electron shells and eight valence electrons.
4. The Lewis dot model use structures that represent the valence electrons of atoms within a molecule existing as lone pairs or when involved in bonding. They can be used to draw electrons that are involved in a collision during a chemical reaction.
Using the model,what is the mass of the atom pictured?
A)3amu
B)5amu
C)7amu
D)9amu
Answer:
with 20 protons (p=20) and 22 neutrons (n=22)? 47 ... Listed below are the charges and masses of four ... a) +2,2 amu c ) +1, 1 amu least b) ... pudding” Model.
Explanation:
Answer:
7amu
Explanation:
Atoms are composed of three particles. The proton, neutron, and electron.
The mass of the atom in amu is just the number of protons and neutrons in the nucleolus since they both have a mass of about 1 amu. Electrons are not counted since they have an incredibly small mass that ultimately does not matter.
This atom has 3 protons (positively charged particle) and 4 neutrons (particle with no charge) which together gives a mass of 7 amu.
true or false, the change from a gas to a liquid is condesation
Answer:
true
Explanation:
i hope this is right your welcome
Answer:
The definition of Condensation is the conversion of a vapour or gas to a liquid, so therefore, this can be proven as a true statement.
A group of scientists are studying the microhabitat on the inside of a hollow log. Twice a year, they take samples of the wood and make observations about organisms living in the log. They observe that the types of bacteria and fungi living in the log change over time. The properties of the wood inside of the log also change.
Which of the following statements best describes why the types of organisms in the log change over time?
A.
Some organisms are adapted to live in a wide range of conditions.
B.
Organisms in the log do not compete for available resources.
C.
Organisms in the log stabilize the conditions in their environment.
D.
Different organisms are adapted for different conditions.
Answer:
D
Explanation:
I took a study island on this
An aluminum isotope consists of 13 protons, 13 electrons, and 14 neutrons. What is its mass number? *
Answer:
26.981539
Explanation:
which information does the chemical formula co2 not give you?
A. number of valence electrons in each atom
B. ratio of atoms in the compound
C. total number of atoms in one molecule of the compound
D. type of elements in the compound
Answer:
A
Explanation:
Considering the definition of chemical formula, the correct answer is option A): number of valence electrons in each atom.
A chemical formula is the representation of the elements that make up a compound and the proportion in which they are found, or the number of atoms that make up a molecule.
In other words, a chemical formula is an alphanumeric expression that is used to indicate the composition of a chemical substance and that is constructed from the symbols of its constituent elements, affected by numerical subscripts that report the number of atoms of each element that it is part of the substance.
In summary, the correct answer is option A): number of valence electrons in each atom.
Learn more:
https://brainly.com/question/18452587?referrer=searchResultshttps://brainly.com/question/21406550?referrer=searchResultsBalance this equation pls
__NaCl + __CaF2→ __NaF +__CaCl2
Answer:
2NaCl + 1CaF²--------》2NaF + 1CaCl²
Answer:
2NaCl + CaF2 >>> 2NaF + CaCl2
if you had 15 moles of Oxygen (O2), how many moles of water (H2O) would you be able to make?
Answer:
30 moles of water will produced.
Explanation:
Given data:
Number of moles of O₂ react = 15 mol
Number of moles of water formed = ?
Solution:
Chemical equation:
2H₂ + O₂ → 2H₂O
Now we will compare the moles of water with oxygen.
O₂ : H₂O
1 : 2
15 : 2×15 = 30 mol
30 moles of water will produced.
Help!!!!!!!!!!!!!!!!!!
The density of the sample : 0.827 g/L
Further explanationIn general, the gas equation can be written
[tex]\large {\boxed {\bold {PV = nRT}}}[/tex]
where
P = pressure, atm , N/m²
V = volume, liter
n = number of moles
R = gas constant = 0.082 l.atm / mol K (P= atm, v= liter),or 8,314 J/mol K (P=Pa or N/m2, v= m³)
T = temperature, Kelvin
n= 1 mol
MW Neon = 20,1797 g/mol
mass of Neon :
[tex]\tt mass=mol\times MW\\\\mass=1\times 20,1797 =20.1797~g[/tex]
The density of the sample :
[tex]\tt \rho=\dfrac{m}{V}\\\\\rho=\dfrac{20,1797}{24.4}=0.827~g/L[/tex]
or We can use the ideal gas formula ta find density :
[tex]\tt \rho=\dfrac{P\times MW}{RT}\\\\\rho=\dfrac{1\times 20.1797}{0.082\times 298}\\\\\rho=0.826~g/L[/tex]
how can you tell if an element has been reduced?
Answer:
Chemists keep track of how electrons are transferred between atoms in a reaction using an oxidation number. If the oxidation number of an element in the reaction increases or becomes less negative, the element has been oxidized, while a decreased or more negative oxidation number means the element has been reduced.
Answer:
It has more electrons in the product than in the reactant
Explanation:
A p e x
What is the volume of 50.0 g of table sugar if the density of the sugar is 1.59 gcm3 ?
Answer:
31.45 cm³Explanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\[/tex]
From the question we have
[tex]volume = \frac{50}{1.59} \\ = 31.446540...[/tex]
We have the final answer as
31.45 cm³Hope this helps you
What is the correct name for the following compound? "Make sure you are using correct naming
rules"
Answer:
c
Good luck on your assessment!
The period of daylight experienced each day on every part of Earth would be shorter if which one of the following changes occurred?
A Earth had a greater diameter.
B The mass of the Sun was greater.
C Earth rotated more quickly on its axis.
D The Sun was farther away from Earth.
Answer:
c
Explanation:
Rubidium is a soft, silvery-white metal that has two common isotopes, 85Rb and 87Rb. If the abundance of 85Rb is 80% and the abundance of 87Rb is 19.8%, what is the average atomic mass of Rubidium?
The average atomic mass of Rubidium : 85.226 u
Further explanationIsotopes are atoms whose no-atom has the same number of protons while still having a different number of neutrons.
So Isotopes are elements that have the same Atomic Number (Proton)
Atomic mass is the average atomic mass of all its isotopes
In determining the mass of an atom, as a standard is the mass of 1 carbon-12 atom whose mass is 12 amu
Mass atom X = mass isotope 1 . % + mass isotope 2.%
The abundance of 85Rb is 80% and the abundance of 87Rb is 19.8%, so the average atomic mass of Rubidium :
[tex]\tt the~average~atomic~mass=0.8\times 85+0.198\times 87\\\\the~average~atomic~mass=\boxed{\bold{85.226~u}}[/tex]
Which of the following has the larger atomic radius?
O Cs
O Ca
O Li
O Ba
Hope it helps
2 points
This occurs if milk overheats. Solids settle on the sides and some fall into
the bottom of the pan. It may caramelize, burn and develop an off-flavor.
Scorching
Scalding
Curdling
Foaming
Answer:
curdling.
Explanation:
How many moles are in 1.81 x 1024 molecules of CO2?
Answer:
3.01 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{1.81 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 3.006644...[/tex]
We have the final answer as
3.01 molesHope this helps you
Without looking at the periodic table, identify the group, period, and
block in which the element that has the electron configuration [Xe]6s2 is
located
the group : 2
periode : 6
block = 2
atomic number = 56
Further explanationWe can divide the periodic system into several parts:
1. Block s: groups 1 and 2 (having a configuration of 1s-7s) consist of active metals except for H (non-metals) and He (noble gases)
2. Block p: group 13-18 (has a 2p-6p configuration), also called a representative element because it includes metals, non-metals and metalloids
3. Block d: group 3-12 (having the 3d-6d configuration), are transition metal elements
4. Block f: Lanthanides and Actinides (having a 4f-5f configuration), are inner transition elements that are also metal
The element with the electron configuration : [Xe]6s²
The outer shell 6s² :
Electron configuration :
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s² : electron =56
group⇒valence electron ⇒2
period⇒the greatest value of the quantum number n⇒6
The element that is in period 6, and belongs to group 2 and has the atomic number 56 and in the block s
Which measurement is a vector?
How many cells could form from one frog egg cell and three hours
Answer:
Some cells, such as the frog egg cells shown here, divide every 30 minutes, and others take as long as a year! The table below compares the length of different cell cycles. 2. With each cell cycle, two cells form from one cell.
After 3 hours, the number of cells formed from one frog egg cell has been 64.
The division of the frog cell occurs every 30 minutes. Thus in 3 hours, the number of divisions occurs:
30 minutes = 1 division
3 [tex]\times[/tex] 60 minutes = [tex]\rm \dfrac{1}{30}\;\times\;180[/tex]
= 6 divisions.
The number of cells formed after n divisions can be given by = [tex]\rm 2^n[/tex]
where n is the number of division cycles.
The number of cells after 6 division cycles = [tex]\rm 2^6[/tex]
The number of cells = 64.
After 3 hours, the number of cells formed from one frog egg cell has been 64.
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Identify the number of protons and electrons
in fluorine and iodine.
The element fluorine helps prevent tooth decay and is found in many toothpastes,
Atomic number: 9
Answer:
Fluorine has 9 protons and 9 electrons
Iodine has 53 protons and 53 electrons
Explanation:
Fluorine has 9 protons and 9 electrons and Iodine has 53 protons and 53 electrons.
What is an electron?An electron is defined as a subatomic particle which is charged negatively either bound to an atom or not it means they are freely found. The nucleus of an atom is made up of electron, proton and neutron. The electron is a basic particle and electron is not made of anything.
The nature of electron is free it means they are present freely in nature and an atom consist of electron.The main function of electron is that function of negatively- charged component of an atom.
The electrons are primary function of current conducting and electrons number as well as atomic number of an element is always same or equal. There is no size of electron but the mass of electron is 9×10^-31.
Therefore, Fluorine has 9 protons and 9 electrons and Iodine has 53 protons and 53 electrons.
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Which orders the activities from the greatest to least impact to reduce consumption of fossil fuels?(1 point)
carpool to work, walk to work, drive an electric car to work
walk to work, carpool to work, drive alone to work
drive an electric car to work, walk to work, carpool to work
drive alone to work, drive an electric car to work, carpool to work
Answer:
walk to work, carpool to work, drive alone to work
Explanation:
Which of the following is NOT a physical property?
A. melting point
B. state of matter
C. density
D. flammability
Answer:
i think.its D ddddddddddddd
Most recent fossils are found in which layer of rock?
Answer: The most recent three layers are the Paleozoic, Mesozoic, and Cenozoic. These layers represent the last 500 million years of life on earth. In the Paleozoic, you find fish, amphibian, and reptile fossils (in that order), but never dinosaurs, birds, modern mammals, or even flowering plants.
Explanation:
Most recent fossils are found in Paleozoic, Mesozoic, and Cenozoic. The type of rock is sedimentary rock.
What are fossils?Fossils are defined as the well-preserved remnants of plants and animals whose carcasses were buried beneath ancient seas, lakes, and rivers in sediments like sand and muck. There are several ways that fossils are created, but the majority occur when an animal or plant dies in a wet environment and is buried in mud and silt.
A new fossil species has been found in a fossil deposit close to Llandrindod Wells in central Wales, according to an international team of experts. Numerous characteristics of Cambrian fossil Mierridduryn bonniae are shared by both. Rock and sediment layers build up on top of one another over time. The oldest and youngest rock layers are always found in reverse order.
Thus, most recent fossils are found in Paleozoic, Mesozoic, and Cenozoic. The type of rock is sedimentary rock.
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Wax melts when it is heated. Which most likely describes what is true of the result of this reaction?
The bonding of the atoms is not the same before and after the change.
The wax has the same density before and after the change.
The same amount of wax exists before and after the change.
The wax cannot be changed back into a solid.
quickly help!!!
Answer:
The same amount of wax exists before and after the change.
Explanation:
Answer:
c -the same amount of wax exists before and after the change-
Explanation:
I did the quiz (edg.) :)
Some notes for you:
A physical change is a change in some of the physical properties of matter, but not in its identity.Wax melting is an energy change, and the energy change can be reversed, which means the wax cools into hard wax again. The wax didn't leave, nor did it somehow get less of it. It stays the same! :)I hope you have an amazing day, I mean it. God bless you!
john 7:37 <3
A car travels 65 miles in 1 hour. What is the average speed of the car?
Complete the following nuclear bombardment equation by filling in the nuclear symbol for the missing species.
²³⁵₉₂U + ¹₀n → ? + ¹³⁹₅₄Xe + 3 ¹₀n
Answer:
Strontium [tex]94_{38}[/tex]Sr
Explanation:
By the law of mass conversion the nuclear mass remains constant in a reaction which means initial mass and atoic number will be equal to final atomic number and atomic mass respectively.
²³⁵₉₂U + ¹₀n → ? + ¹³⁹₅₄Xe + 3 ¹₀n
Here atomic mass =
235 + 1 = A + 139+3 ( A -= atomic mass of ?)
A = 236 - 142
A = 94
And, atomic number would be =
92 = B + 54
B = 92 - 54
B = 38
So, the atomic number of ? will be 38 and atomic mass will be = 94
The element with 38 atomic number is = Strontium [tex]94_{38}[/tex]Sr
The missing species in the equation is ⁹⁴₃₈Sr
Let the missing species be ᵇₐY
We can write the equation as:
²³⁵₉₂U + ¹₀n → ᵇₐY + ¹³⁹₅₄Xe + 3¹₀n
Next, we shall determine the value of b235 + 1 = b + 139 + 3(1)
236 = b + 139 + 3
236 = b + 142
Collect like terms
236 – 142 = b
b = 94Next, we shall determine the value of a92 + 0 = a + 54 + 0
92 = a + 54
Collect like terms
92 – 54 = a
a = 38Finally, we shall determine Yb = 94
a = 38
Y =?ᵇₐY => ⁹⁴₃₈Y => ⁹⁴₃₈Sr
The balanced equation is:
²³⁵₉₂U + ¹₀n → ⁹⁴₃₈Sr + ¹³⁹₅₄Xe + 3¹₀n
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Which one is not acid? Na₂O or CO₂
Answer:
It is Na2O because it doesn't show any acidic properties.