Answer: C2Br6
Explanation:
What is the mass of 0.55 mole
of magnesium chloride?
Answer:
SYMBOLS, FORMULAS AND MOLAR MASSES
OBJECTIVES
1. To correctly write and interpret chemical formulas
2. To calculate molecular weights from chemical formulas
3. To calculate moles from grams using chemical formulas
INTRODUCTION
Part I. Symbols and formulas
An element is a homogeneous pure substance made up of identical atoms. All matter is made
up of elements and, since chemistry is the study of matter, it is convenient to use symbols to represent
the elements rather than using the entire name.
By international agreement, specific symbols are assigned to each element (Note: This means
that while names of the elements vary with language, symbols are constant throughout the world.) Each
element is assigned a one- or two-letter symbol. The first letter is capitalized, the second (if there is
one) is not. While this often seems trivial, it is in fact a very important point. For example, in chemical
language Co represents cobalt, which is a metal and an element, while CO represents carbon monoxide,
a compound which is a colorless, odorless gas! Even when there is not an obvious correspondence,
for instance "MN", it can cause confusion. Do you mean the element manganese? Did you forget a
letter and mean something else? Are you using "M" to represent something else entirely? Chemists
sometimes use "M" to represent any metal. It is well worth the trouble to memorize the symbols for
common elements.
Since compounds consist of elements, the chemical formulas of compounds also consist of
elements with subscripts used to denote the number of atoms per molecule. If there is no subscript, it is
implied that there is one of that kind of atom. Ones never appear in chemical formulas. Not only do
subscripts denote ratios of atoms, they also denote the ratio of moles of element to one mole of
compound. Parentheses can be used to show groups of atoms, with the subscripts showing how many
groups there are. Parentheses are not used if there is only one group.
Examples: For one mole of the following compounds, how many moles of each element are
present?
MgCl2 1 mole Mg, 2 moles Cl
Mg(NO3)2 1 mole Mg, 2 moles N, 6 moles O
NaNO3 1 mole Na, 1 mole N, 3 mole O
AgCl 1 mole Ag, 1 mole ClPart II. Molar Masses
Each atom has a different size and therefore a different mass. The relative masses of each
element can be found on the periodic table. For example, one atom of magnesium weighs 24.31 amu
(atomic mass units). However, one mole of magnesium weighs 24.31 g. (Moles were planned that
way!) Since one mole of MgCl2 consists of one mole of magnesium and two moles of chlorine, the
mass of one mole of MgCl2 must be the sum of the masses of the elements. The mass of one mole of a
substance is called the molar mass or molecular weight.
Examples: What is the molar mass of the following compounds?
MgCl2 24.31 + 2(35.45) = 95.21 g/mol
Mg(NO3)2 24.31 + 2(14.01) + 6(16.00) = 148.33 g/mol
NaNO3 23.00 + 14.01 + 3(16.00) = 85.01 g/mol
AgCl 107.9 + 35.45 = 143.4 g/mol
(Note: Yes! You DO have to count significant figures when calculating molecular weight/molar
mass. However, the number of significant figures may vary depending on which periodic table you use.)
Chemists are generally interested in number of moles. Unfortunately, it is impossible to measure
moles directly. However, masses are easily measured, and if the chemical formula of the compound is
known, the molar mass can be used to determine the number of moles. The molar mass is defined as:
molar mass = grams/moles = g/mol (1)
Moles may be calculated by using molar mass as a conversion factor in dimensional analysis where
molar mass in grams = 1 (exactly) mole of compound (2)
This method is used in multi-step calculations. For example, if 0.873 g of MgCl2 is weighed out, it
is 9.17 x 10-3
moles.
1 mole
0.873g x 95.21 g = 9.17 x 10-3
mol MgCl2 (3)
However, 0.873 g of AgCl is only 6.09 x 10-3
mol.
1 mole
0.873g x 143.4 g = 6.09 x 10-3
mol AgCl (4)Molar mass may also be used to relate moles to grams. For example, 0.158 mol of MgCl2 is 15.2 g.
0.158 mol x 95.21 g = 15.2 g MgCl2 (5)
1 mol
Percent is used to express parts per one hundred. Usually in chemistry, it refers to
g of species of interest x 100 = % (6)
g of whole thing
Example: For the % Mg in MgCl2: In one mole of MgCl2, there are 24.31 g of Mg (molar mass of Mg,
the part we are interested in) and 95.21 g of MgCl2 (the whole thing), so %Mg in MgCl2 is
(24.31/95.21) x 100 = 25.53% Mg (7)
PROCEDURE
Work individually.
The formula for calcium phosphate is Ca3(PO4)2. Weigh about 2 g of calcium phosphate to the
nearest 0.001 g. In other words, you do not have to have exactly 2.000g, but you must know the
weight you have exactly. Acceptable results include but are not limited to: 1.985g , 2.035g, 2.314g
etc.
Be sure to report all results with the correct number of significant figures and appropriate units!
Which of the following would happen if Earth's moon were half the size that it is now? O The oceans' tidal variations would be smaller because the Moon would exert less gravitational pull on Earth's oceans. O The oceans' tidal variations would be greater because the Moon would exert less gravitational pull on Earth's oceans. O The oceans' tidal variations would be greater because the Moon would exert more gravitational pull on Earth's oceans. The oceans' tidal variations would be smaller because the Moon would exert more gravitational pull on Earth's oceans. & Previous
Answer: A. The oceans‘ tidal would be smaller because the moon would exert less gravitational pull on earths oceans.
Explanation:
i got it right :)
what kind of substance is rust
Give examples of kinetic energy and how they work.
Answer: The kinetic energy of an object depends on both its mass and velocity, with its velocity playing a much greater role. Examples of Kinetic Energy: ... A baseball thrown by a pitcher, although having a small mass, can have a large amount of kinetic energy due to its fast velocity.
Explanation:
Hope this help
The air we breathe contains different individual gases (mostly nitrogen and oxygen). Which of the following correctly describes the air we breathe?
a
element
b
compound
c
mixture
d
none of these
PLEASE HELP Will give brainliest and 50 points!! Please give honest answers
A magnet is different from a piece of iron that is not magnetic because
Answer:
Under normal conditions, a magnetic material like iron doesn't behave like a magnet because the domains don't have a preferred direction of alignment. On the other hand, the domains of a magnet (or a magnetized iron) are all aligned in s specific direction.
Explanation:
At certain times of year , the oceans get warmer. Which part of the water cycle is directly affected by the warming of the ocean water?
HELP! URGENTLY NEEDED! I NEED THIS ANSWER IN 5 MINUTES AND PERSON WHO HELPS GET THE ANSWER RIGHT GETS 25 POINTS!!! PLEASE I AM FAILING THIS CLASS AND NEED SO MUCH HELP!!!!
The coefficient/s will balance the chemical equation CH4 +O2 -------» CO2 + H2O is
a
1, 2, 1, 2
b
2, 1, 1, 2
c
2, 2, 1, 1
d
1, 1, 1, 2
Answer:
hey miss
Explanation:
The coefficients : a. 1,2,1,2
Further explanationGiven
Reaction(unbalanced)
CH4 +O2 -------» CO2 + H2O
Required
The blanced equation
Solution
Give a coefficient
CH4 +aO2 -------» bCO2 + cH2O
Make an equation
C, left=1, right=b⇒b=1
H, left=4, right = 2c⇒2c=4⇒c=2
O, left=2a, right=2b+c⇒2a=2b+c⇒2a=2.1+2⇒a=2
The equation becomes :
CH4 +2O2 -------» CO2 + 2H2O
Need help plz!
-Which property describes a mixture?-
A. It cannot be separated by physical methods.
B. It has a single chemical composition.
C. It cannot have more than one state of matter.
D. It cannot be described by a chemical symbol or formula.
Answer:
D as a mixture is not a compound and it does not have it's own chemical formula
Explanation: Sauce me brainliest
It cannot be described by a chemical symbol or formula.
- Chilio
✨✨What’s 2 similarities and 2 differences between the Earths layers and the atmospheric layers? ✨✨
‼️DONT COPY OFF LINE PLEASE ‼️
Answer:
Differences: Earth's atmosphere has 5 main layers where as atmospheric layers thins out in each higher layer.
Similarities: They both have multiple layers.
Explanation:
Sorry I only have 1 difference and similarity.
For each type of fuel shown in the table above (H2, CH4, O2), how much energy should
be added to the system in order to break the bond between the atoms forming the
molecule of the fuel?
Answer:
Explanation:
Chapter 4: Energy from Combustion The primary means of generating energy for human
endeavors is the combustion of fuels.
Coal - burned in power plants
Gasoline - burned in automobiles
Natural gas - heating
Heating oil – heating
.Propane, charcoal, wood, candles, …
Combustion (burning in air) releases the chemical energy,stored in the chemical bonds of the fuels.
BRAINLY PLZ
How many moles of a gas sample are in a 5.0 L container at 373 K and 203 kPa?
0.33 mole
0.66 mole
1.11 moles
3.05 moles
Answer:0.33
I'm not sure tho
Answer:
0.33
I just took the test.
what volume of 0.20 M NaCl contains 10.0 g
If one mole of an unknown substance is 200.59 g/mole, what is the mass of 0.33 moles of that substance?
Answer: 66.83g
Explanation: (200.59 g/mole = Hg)
0.33 moles = 66.83g
An 240. mL sample of oxygen at 90.00C and was cooled at constant pressure
until it has a volume of 450.0 mL. What was the final Celsius temperature of this
gas? *
The final temperature : T₂ = 680.625 K
Further explanationGiven
V₁=240 ml
T₁ = 90 + 273 = 363 K
V₂ = 450 ml
Required
The final temperature
Solution
Charles's Law
When the gas pressure is kept constant, the gas volume is proportional to the temperature
[tex]\tt \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]
Input the value :
T₂ = V₂T₁/V₁
T₂ = 450 x 363 / 240
T₂ = 680.625 K
Newton's first law is demonstrated in what station?
Answer:
hope this helps!
Explanation:
This law states that a still object will stay still unless a force pushes or pulls it. A moving object will stay moving unless a force pushes or pulls it. Gravity and friction are forces that constantly push and pull the "stuff" on earth. So, when we roll a ball, it slowly comes to a stop.
What is the molar mass of Al(NO3)3 · 3H2O?
Answer:
Go to your periodic table and look for each element. Find the mass for Aluminum, Nitrogen, Oxygen, and Hydrogen.
After you find those, for each compound you must add them together and find the least amount of sig figs after the decimal point.
For the first compound, Al(NO3)3, you will have a total of
1 Aluminum atom
3 Nitrogen atoms
9 Oxygen atoms
Aluminum has 26.982 g/mol
Nitrogen has 14.007 g/mol
Oxygen has 15.999 g/mol
Now multiply those numbers by the amount of atoms of each element.
(1)26.982 g/mol = 26.982 g/mol
(3)14.007 g/mol = 42.021 g/mol
(9)15.999 g/mol = 143.991 g/mol
now add all of those numbers together, and you see that their least significant figure after the decimal is 3, so round to 3 digits after the decimal point.
26.983 + 42.021 + 143.991 = 212.994
now do the same for the other compound
to start you off.. you have
6 Hydrogen atoms
3 Oxygen atoms
Hydrogen has 1.009 g/mol
Oxygen has 15.999 g/mol
the least significant figure after the decimal point is 3, so round you 3 digits after the decimal point.
after you finish getting your totals, you. until them and find the greatest sig fig over all. comment on this if you need further instruction :)
Question 5
Which of the following is not an example of mutualism?
pls help 6th grade science
1.
What is the light that you can see called?
VED
DANCE
WOW
EN
M
W
NOGO
OLET
a) observatory light
c) visible light
b) ultraviolet light
d) infrared light
Answer:
The correct answer is c. Your welcome
Why did Mendeleyev try to reorganize the periodic table?
Review the poster.
https://www.cdc.gov/handwashing/pdf/wash-your-hands-fact-sheet-508.pdf
What is the greatest advantage of using a poster to present the information in “Stop Germs! Wash Your Hands”?
A poster that features brief sentences conveys urgency and simplifies content.
The extensive detail in posters captures viewers and causes them to stop and read.
The colors and images of a poster often convey a stronger message than words.
A poster appeals to several senses at once, which makes it hard to ignore.
A. A poster that features brief sentences conveys urgency and simplifies content.
Help thanks thanks thanks
Answer:
the answer is (G)
Explanation:
It is G!
Your welcome!
lons form when atoms gain or lose valence electrons. When an atom gains
electrons, it becomes negatively charged, and when an atom loses
electrons it becomes positively charged. Why?
Answer:
In neutral atom number of electrons (negativity charged particle) and number of proton ( positively charged particle) are equal.
When one or more electrons are lost so positive charge particle increases and cation is formed.
For example in Na 11 electrons and 11 protons are present when it loses one electrons protons are 11 and 10 electron are remaining so one positive charge is present.
Morever when an element gain electrons one negative charge increases and anion is formed. For example in Cl 17 proton and 17 electrons are present when it gain one electron 18 electrons and 17 protons are now present one negative is more so anion negative ion is formed.
Explanation:
1.State the relationship between the following properties:
a) mass and number of moles__________
b) number of moles and number of particles __________
6. Show how you will compute for the number of particles given the following:
a) Mass of the sample__________
b) Number of moles of the sample__________
Thankyouu po sana my mag answer
Answer:
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Give an example of an object that has potential energy
Answer:
A book on a shelf
Explanation:
PLEASE HELP!!!!!!!!!!!!!!!!!!!! ASAP!!!!!!!!! Which two elements are mainly found in the inner and outer core?
A. Fe and Ni
B. Fe and Si
C. Ni and Si
D. Ni and C
PLEASE TELL ME WHAT THOSE ABREVIATIONS MEAN ALSO!!!!!!!!!!!!!
Something that is made out of natural resources for human use is called? Synthetic Resource Natural Resource Materials Living Organisims
Answer:
Natural Resource
Explanation:
A natrual resource is something that was created when Earth was first made. They were intended to fulfill human needs when they needed them. An example of a natural resource can be water, because we will need water to survive.
18. What is the molarity of a bleach solution containing 9.5 g of NaOCL per liter of bleach
Answer:
0,1276 M
Explanation:
Molair mass of NaOCl = 74,44 g/mol
You have 9,5 g/L.
You need to calculate with the molair mass, how many moles 9,5 g are:
9,5 g / 74,44 g/mol = 0,1276 mol
0,1276 mol / 1 L = 0,1276 M
The molarity of a bleach solution containing 9.5 g of NaOCL per liter of bleach is mathematically given as
M= 0.1276 M
What is the molarity of a bleach solution containing 9.5 g of NaOCL per liter of bleach?Generally, the equation for the Molar mass is mathematically given as
M=m/(g/mol)
Therefore
M=9,5 g / 74,44 g/mol
M= 0,1276 mol
Hence
M= 0.1276 M
In conclusion, the molarity
M= 0.1276 M
Read more about Molarity
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