Please help (: List and describe the locations and conditions in the Four zones of a lake

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!

Answer:

YESSIR

Explanation:

Answer:

x^2 - a^2

Explanation:

Answer:

-175.15

Explanation:

1.0 °C = 274.15 K

2.0 °C = 275.15 K

3.0 °C = 276.15 K

4.0 °C = 277.15 K

5.0 °C = 278.15 K

6.0 °C = 279.15 K

7.0 °C = 280.15 K

8.0 °C = 281.15 K

9.0 °C = 282.15 K

Answer:

Yes, a chemical bond is a lasting attraction between two atoms. (I am not completely sure what you mean, but I hope this helps!)

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 :)

Answer:

To catch a ball, the fielder has to stop the ball. This means, force is applied against the motion of the ball. So, between the fielder applies force on the ball and the ball comes to rest, the ball moves in the direction opposite to the direction of force. Thus work is negative.

Explanation:

MARK ME AS BRAINLIEST PLSSS

Answer:

reactants contain more energy in the decomposition reaction of sodium azide?

Explanation:

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. A poster that features brief sentences conveys urgency and simplifies content.

Answer:

A book on a shelf

Explanation:

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

Answer: The nucleus is often referred to as the control center, or brain, of the cell and contains the DNA, or genetic material. The nucleus is surrounded by the nuclear envelope. ... Human cells are eukaryotic cells.

Explanation:

Answer:

Nucleus

Explanation:

not to good at explaining but I'm hoping this is right!

Answer:

⇒ n = 2.4088 × 10²⁴

- So, the no of atoms in 4 moles of helium is 2.4088 × 10²⁴.

Explanation:

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:

Answer:

True

Explanation:

because it never stops doing it

Answer:

bytbyufvguv vvg uggy yvgu vgu gyu7yng8ugng88yn

Answer:

[tex]\boxed {\boxed {\sf 301.325 \ Joules }}[/tex]

Explanation:

Since we are given the mass, specific heat, and change in temperature, we should use this formula for energy:

[tex]q=mc \Delta T[/tex]

The mass of the graphite is 25 grams. Graphite's specific heat is 0.709 J/g °C. The change in temperature is 17 degrees Celsius.

[tex]m= 25 \ g \\c= 0.709 \ J/g \ \textdegree C \\\Delta T= 17 \ \textdegree C[/tex]

Substitute the values into the formula.

[tex]q= (25 \ g)( 0.709 \ J/g \ \textdegree C )( 17 \ \textdegree C)[/tex]

Multiply the first two numbers. The grams will cancel.

[tex]q= 17.725 \ J/ \textdegree C(17 \ \textdegree C)[/tex]

Multiply again. This time the degrees Celsius cancel.

[tex]q= 301.325 \ J[/tex]

The graphite loses 301.325 Joules of energy.

Answer:

the answer is (G)

Explanation:

It is G!

Your welcome!

Answer:

The correct answer is c. Your welcome

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