Show your work with good use of units, rounding, and significant figures. [Hint: it is good practice to show the value of your answer before you round off to the final answer with the correct significant figures!]
(8 points) How much heat is required to convert 10.00 g of ice at –20.00°C to water at 25°C. The specific heat of ice is 2.09J/g°C; the specific heat of water is 4.182 J/g°C; the heat of fusion is 333.0 J/g.
Group of answer choices
Heat required : 4.8 kJ
Further explanationThe heat to change the phase can be formulated :
Q = mLf (melting/freezing)
Q = mLv (vaporization/condensation)
Lf=latent heat of fusion
Lv=latent heat of vaporization
The heat needed to raise the temperature
Q = m . c . Δt
1. heat to raise temperature from -20 °C to 0 °C
[tex]\tt Q=10\times 2.09\times (0-(-20)=418~J[/tex]
2. phase change(ice to water)
[tex]\tt Q=10\times 333=3330~J[/tex]
3. heat to raise temperature from 0 °C to 25 °C
[tex]\tt Q=10\times 4.18\times (25-0)=1045~J[/tex]
[tex]\tt Q~tot=418+3330+1045=4793~J\rightarrow rounding~and~2~sig~figs=4.8~kJ[/tex]
You mix 15g of water with 10 grams of sodium chloride. After the reaction occurs, how
many grams of your new substance do you have?
A) 15g
B) 25g
C) 20g
D) not enough information
Answer:
B) 25g
Explanation:
Every reaction must follow the law of conservation of mass.
Law of conservation of mass:
According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.
Explanation:
This law was given by French chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
For example:
In given photosynthesis reaction:
6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂
there are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.
In given example:
Water + sodium chloride → Product
15 g + 10 gram = 25 g
25 g = 25 g
THIRTY POINTS I NEED HELP HURRY What is the volume of the cone?
Answer:
V=πr2h 3
Explanation: I would give more but need more i information
Answer:there u go
Explanation:The volume V of a cone with radius r is one-third the area of the base B times the height h . Note : The formula for the volume of an oblique cone is the same as that of a right one. ... If the heights of a cone and a cylinder are equal, then the volume of the cylinder is three times as much as the volume of a cone
atoms are so small that approximately _______ of them can fit at the end of a needle?
Answer:
5 million million atoms can fit at the end of a needle
Answer:
Let's just say 5 million million hydrogen atoms could fit at the end of a needle.
Explanation:
Atoms are 100 picometers, and to compare, the amount of even 1 centimeter, a calculator can't even figure out how many picometers are in a centimeter because there is just too much picometers.
Think about how particles are arranged inside atoms. Please name and describe those three particles, and describe how the particles are arranged inside atoms. Some topics to include are: the charge of the particles, the mass of the particles, and where the particles are located.
A reversible reaction is said to be in equilibrium when
A)
all reactions stop leaving some reactant unused.
B)
the reaction goes to completion and no reactants are left.
9)
the rate of the backward reaction equals the rate of the forward reaction.
D)
the reaction rate of the backward reaction becomes larger than the rate of
the forward reaction.
Answer: C) the rate backward reaction equals the rate of the forward reaction.
Explanation:
Explain why the electron configuration of 2-3-1 represents an atom in an excited state?
Answer:
See explanation
Explanation:
If we look at the electron configuration closely, we will discover that the element must have had a ground state electron configuration of 2,4.
This is because, the innermost shell usually holds two electrons while the outer shells hold eight electrons each. The four electrons must be accommodated in the second shell in the ground state configuration of the compound.
However, when the atom is excited, one electron from this shell may move to the third shell to give the excited state configuration 2-3-1 as shown in the question.
How do HOT AIR BALLOONS work when ascending and descending explain in terms of gas behavior?
Answer: Animation: Burning gas makes the air inside the balloon less dense, producing an upward force or lift. 1) A hot air balloon stays on the ground (or descends) when the air inside it is too cool. ... 3) When the air is hotter still, the balloon rises because the lift force is greater than the weight.
Explanation:
Common sense
Solid carbon dioxide (CO2), also known as dry
ice, changes into a gas at room temperature. An
image of this change can be seen below.
Is this an example of a physical change? Why
or why not?
Answer:
yes
Explanation:
yes because the ice changes forms physically and can be changed back. not 100% sure tho
Answer:
shiii ion even know like i cant even tell u tha
Explanation:
bro 2 of my bruddas got locked up 2 days ago one of em got shot before the cops took him
The elements on the Periodic Table of the Elements are arranged in order of increasing
Answer: The Atomic Number increases. Hope this helps!!!
Explanation:
Elements are arranged from left to right and top to bottom in order of increasing atomic number. Order generally coincides with increasing atomic mass.
Answer:
The Atomic number increases....
Explanation:
Duh
another science question plz answer ASAP b/c its timed
Answer:
D
Explanation:
Which is greater 50 degree celcius or 50 degree fahrenheit?with solution plz.....
Answer: 50 degrees Celsius is hotter than 50 degrees F. 50 degrees Celsius is half way between freezing and boiling
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 Assignment: Locating the Epicenter, What was the length of the radius of the circle of from the Buenos Aires station? (in cm)
Question 1 options:
3.2 cm
4.8 cm
5.76 cm
8 cm
if u know that answer i will mark has brainliest
Answer:
The clear liquid is less dense than the black liquid, which is why it floats on top. If the volume were different, you would visually see more clear liquid than black and vice versa.
The clear liquid is less dense than the black liquid
Answer:
A. The clear liquid is less dense than the black liquid
Explanation:
Since the clear liquid since on top of the black one it's density is less. Whatever liquid has a higher density will sink to the bottom of the flask.
are Li, Na and K in the same group
Answer: Yes, they are.
Explanation:
Yes, they are. Li, Na, and K are referring to Lithium, sodium, and potassium.
They are all belonging to the same group which is called the alkali metals group.
They are having the same number of valence electrons i.e. 1.
This group of the alkali metals are considering tree more metals in it which are Rb, Cs, and Fr.
Why are you able to smell things across a room or form great distances
Answer:
We smell hot food from distance because of the diffusion process. Diffusion is the spreading out and intermixing of particles From one substance into another substance due to the movement of particles.
Explanation:
Observe: Look at the red lithium atom and the blue oxygen atom. Recall that most atoms are stable when their outermost ring has eight electrons. (Some atoms, such as lithium and beryllium, are stable when their outermost ring has two electrons.)
How many electrons will the lithium atom give up to become stable?
1. eight
2. seven
3. two
4. one
Answer:
4. one
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]
Science hmk due tmr morning need help!! pls answer all 3 and number which one is which for example...
1.j
2.j
3.j
true or false, vaporization that occurs at the surface of a liquid is called evaporation
Answer:
True
Explanation:
Vaporization that happens below the surface is boiling, above the surface is evaporation :)
Answer:
True
Explanation:
it evaporates because of the temperature difference
What do you think caused this land formation ?
How are Earth's continents related?
Please help due at 11:45!
Criminalist Julie Sandel is investigating a series of threatening notes written in pencil and sent to a local politician. A suspect is arrested and Julie directs the suspect to prepare writing samples to compare to the writing on the notes. She has the suspect sit at a desk in an empty office and gives him a pen and a piece of paper. She begins to read one of the notes and asks the suspect to write the words she dictates. After reading about half a page, she stops, then dictates the same part of the note a second time for the suspect. At one point, the suspect indicates that he does not know how to spell one of the words, so Julie spells it for him. After completing the task, Julie takes the origi- nal notes and the dictated writing from the suspect to a document examiner. What mistakes, if any, did Julie make?
Answer:
See explanation
Explanation:
Julie Sandel, the Criminalist made several mistakes in handling this investigation. They include;
It is true that handwriting can be deduced by comparing a suspects's handwriting to the questioned document, however Julie made a mistake by not making the suspect to write many pages. The suspect may intentionally decide to change his/her hand writing. This trick can be neutralized by asking the suspect to write several pages.
Secondly, the suspect ought to have been given a pencil and paper similar to the one used to write the threatening document. Rather, Julie gave the suspect a pen.
Thirdly, the suspect only wrote half a page instead of a full page. Secondly, Julie took only two exemplars when she should have taken more.
She should not have dictated the spelling of any word to the suspect. The examiner is not supposed to do that.
The threatening documents should have first been shown to the document examiner before taking the exemplars.
What is the location of elements in the periodic table related to?
Answer:
.
Explanation:
An element's location in the periodic table is largely depending on its electrons. The number of valence shell electrons determines its group, and the type of orbital in which the valence electrons lie in determines the element's block. Sometimes during these groups there are more like the alkali metals the non metals and gases :)
Using the model of the periodic table, which element pictured represents an unreactive gas?
Answer:
2
Explanation:
Nobel gasses are not reactive and are the far right group on the periodic table. This is because they have a full valence electron shell which is the most stable electron configuration. Most reactions occur in order for an atom to fill its valence shell and since they already have a full valence shell there is no reason for them to react.
Identify the following structure as an atom, molecule, or compound molecule.
Hydrogen
A.atoms
B. molecules
C.compound molecules
Answer:
A
Explanation:
The answer is A because Hydrogen is an Atom consists of 1 electron only.
Good luck
I will give you Brainly if you awser correct if your gonna awser for points pl put I don’t know
Answer:
C
Explanation:
What is it called when a rock is broken down into smaller pieces by ice, glacier or water ? Chemical weathering, physical weathering, deposition, pollution
Answer:
deposition I hope this helps!!
Explanation:
Answer:physical weathering
Explanation:
Which of the following atoms has the largest radius?
a. lithium
b. lead
C. cesium
d. fluorine
e. carbon
Explanation:
first one, a. lithium. it's the largest