Answer:
wind can cause rocks to erode and can expose more of the earth crust then before.
True/False: All of the elements combine in a variety of ways to make up all living and all nonliving things
Answer:
true
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!
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
Help thanks thanks thanks
Answer:
the answer is (G)
Explanation:
It is G!
Your welcome!
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?
A sample of nitrogen gas contains 8.23 x 10^23 molecules. What is the volume of this sample at STP?
Please show and explain the steps.
Answer:
30.6 L
Explanation:
Given data:
Number of molecules of nitrogen = 8.23×10²³ molecules
Volume occupy at STP = ?
Solution:
Standard temperature = 273.15 K
Standard pressure = 1 atm
One mole of any substance at STP occupy 22.4 L volume.
Number of moles of nitrogen:
1 mole contain 6.022×10²³ molecules.
8.23×10²³ molecules × 1mol / 6.022×10²³ molecules
1.37 mol
Volume of nitrogen:
1.37 mol × 22.4 L / 1 mol
30.6 L
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 kind of substance is rust
Why did Mendeleyev try to reorganize the periodic table?
One of the main jobs of _________ is to support the leaves
The flowers
the seeds
the roots
the stem
Answer:
Stem
Explanation:
Answer:
option-(d) stem
Explanation:
Stems have four main functions which are: Support for and the elevation of leaves, flowers and fruits. The stems keep the leaves in the light and provide a place for the plant to keep its flowers and fruits. Transport of fluids between the roots and the shoots in the xylem and phloem...
I hope it help you
Why don't we feel the air pressing on us all the time?
Answer: Why don't we feel the air pressing on us all the time?
Explanation:
Because air is a fluid, the weight of the air is transmitted to the palm of your hand and to the back of your hand at the same time. These forces cancel so that your hand overall feels no net force
Answer:the gravity in the atmosphere is pulling all the air so we can survive
Explanation:
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
A doctor prescribes 125 mg of penicillan to be taken 4 times each day. The
concentration of the solution given to the patient is 250mg penicillan/5ml. How
many mL should the patient take in each dose?
1) 500 mL
2) 10.0 mL
3) 2.50mL
4) 50.0 mL
5) 2.0 mL
10 ml should the patient take in each dose
Further explanationGiven
125 mg of penicillan ⇒ 4 times/day
The concentration = 250 mg/5 ml
Required
The volume of the dose
Solution
The mass of penicillan/day :
= 125 mg x 4 times
= 500 mg
The volume/day :
= 500 mg : 250 mg/5 ml
= 10 ml
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!!!!!!!!!!!!!
kind of protists can live in groups with different individuals performing different jobs (site 1)
Answer:
The plasmodial slime molds are the kind of protist that can live in groups in which different individuals perform different jobs. Some kinds of bacterial cell walls also have other functions.
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:
Calculate the atomic mass of oxygen if the three common isotopes of oxygen have masses of 15.995 amu (99.759% abundance), 16.995 amu (0.037 % abundance), and 17.999 amu (0.204 % abundance).
Answer:
16 amu
Explanation:
Give an example of an object that has potential energy
Answer:
A book on a shelf
Explanation:
What does the difference in force depend on?
The total pressure of a mixture of hydrogen, oxygen, and methane is 96.4 kPa. The partial pressures of hydrogen and oxygen are 13.5
kPa and 29.3 kPa respectively. What is the partial pressure of methane?
A. 139.2 kPa
B. 53.6 kPa
C. 82.9 kPa
D. 42.8 kPa
Answer:
53.7kPa
Explanation:
Given parameters:
Total pressure of the mixture = 96.4kPa
partial pressure of hydrogen = 13.4kPa
partial pressure of oxygen = 29.3kPa
Unknown:
partial pressure of methane = ?
Solution:
The total pressure of mixture is equal to the sum of their particles pressures;
Partial pressure of methane = 96.4kPa - (13.4kPa + 29.3kPa)
Partial pressure of methane = 53.7kPa
Answer: 53.6
Explanation: I just took the test and got it right.
As mass decreases, gravitational force ____
increase or decrease
Give an example of kinetic energy
Answer: A river flowing at a certain speed comprises kinetic energy as water has certain velocity and mass. The kinetic energy of an asteroid falling towards earth is very large. The kinetic energy of the aeroplane is more during the flight due to large mass and speedy velocity.
Explanation:
What does the large number in front of
the molecule represent?
Is energy part of the system or surrounding?
Answer:
Se Puede Traducir?
Explanation:
Mmm?
Answer:
i think it is surroundings
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:
bytbyufvguv vvg uggy yvgu vgu gyu7yng8ugng88yn
Question 5
Which of the following is not an example of mutualism?
One mole of silver has a mass of 107.9 grams. Approximately how many atoms of silver are present in one mole of silver?
A) 107 atoms
B) 108 atoms
C) 6 × 1023 atoms
D) 53 × 1023 atoms
Answer C) 6 × 1023 atom
The number of silver atoms present in one mole of silver is 6.0 × 10²³ atoms. The correct option is C) 6 × 1023 atoms
StoichiometryFrom the question, we are to determine the number of silver atoms present in one mole of silver.
From the formula,
Number of atoms = Number of moles × Avogadro's constant
Number of atoms = 1 × 6.022 × 10²³
Number of atoms = 6.022 × 10²³
Number of atoms ≅ 6.0 × 10²³ atoms
Hence, the number of silver atoms present in one mole of silver is 6.0 × 10²³ atoms. The correct option is C) 6 × 1023 atoms
Learn more on Stoichiometry here: https://brainly.com/question/16505596
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
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.
PLEASE HELP Will give brainliest and 50 points!! Please give honest answers