3.67 mol Al
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
2.21 × 10²⁴ atoms Al
Step 2: Identify Conversions
Avogadro's Number
Step 3: Convert
Set up: [tex]\displaystyle 2.21 \cdot 10^{24} \ atoms \ Al(\frac{1 \ mol \ Al}{6.022 \cdot 10^{23} \ atoms \ Al})[/tex]Divide: [tex]\displaystyle 3.66988 \ mol \ Al[/tex]Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
3.66988 mol Al ≈ 3.67 mol Al
Arnold kept a water log as a project for his chemistry class. Arnold's family consists of Arnold, his sister, and his parents for a total family size of four. He measured each family member's water usage every day for a week, and found that the family used an average of 457 gal/day. Arnold's city charges $0.223/cgal of water. The unit centigallon (cgal) is used by cities to measure the volume of water used, where 1 cgal is equal to 100 gal. Assuming this average usage continues, how much does Arnold expect his family to pay in a year for water usage?
Answer:
$ 1487.90 .
Explanation:
Family size = 4
Water usage per member = 457 gal / day .
Water usage for whole family = 457 x 4
Use of water in one year for family = 457 x 365 x 4 = 667220 gal
667220 gal = 667220 / 100 = 6672.20 cgal .
expense per cgal = $ 0.223
Total yearly expected expense = 0.223 x 6672.20
= $ 1487.90
The decomposition of 74.2 g ammonium
nitrate yields how many liters of water a
0.954 atm and 387 K?
NH,NO3(s) → NO g) + 2H,O(g)
Note: Keep extra digits in any intermediate
calculations! Round to the correct number of
significant figures at the very end.
For R, use 0.08206 L atm/(mol K).
Answer:
61.75 L of water
Explanation:
We'll begin by calculating the number of mole in 74.2 g of ammonium nitrate, NH₄NO₃. This can be obtained as follow:
Mass of NH₄NO₃ = 74.2 g
Molar mass of NH₄NO₃ = 14 + (4×1) + 14 + (3×16)
= 14 + 4 + 14 + 48
= 80 g/mol
Mole of NH₄NO₃ =?
Mole = mass / molar mass
Mole of NH₄NO₃ = 74.2 / 80
Mole of NH₄NO₃ = 0.9275 mole
Next, the balanced equation for the reaction. This is illustrated below:
NH₄NO₃ —> N₂O + 2H₂O
From the balanced equation above,
1 mole of NH₄NO₃ decomposed to produce 2 moles of H₂O.
Therefore, 0.9275 mole of NH₄NO₃ will decompose to produce = (0.9275 × 2) = 1.855 moles of H₂O.
Finally, we shall determine the volume of water obtained from the reaction. This can be obtained as follow:
Pressure (P) = 0.954 atm
Temperature (T) = 387 K
Number of mole (n) of H₂O = 1.855 moles.
Gas constant (R) = 0.08206 L.atm/Kmol
Volume (V) of H₂O =?
PV = nRT
0.954 × V = 1.855 × 0.08206 × 387
Divide both side by 0.954
V = (1.855 × 0.08206 × 387) / 0.954
V = 61.75 L
Therefore, 61.75 L of water were obtained from the reaction.
Which of the following processes will determine the number of atoms in a sample?
Dividing the mass of the sample by its molar mass
Multiplying the mass of the sample by its molar mass
Dividing the number of moles of the sample by Avogadro's number
Multiplying the number of moles of the sample by Avogadro's number
Answer:
Multiplying the number of moles of the sample by Avogadro's number
Explanation:
The process that will help determine the number of atoms in a sample is by multiplying the number of moles of the sample by Avogadro's number.
The number of moles of substance has a wide range of application in quantitative chemistry.
A mole of any substance contains the Avogadro's number of particles. The particles can be atoms, molecules, formula units, neutrons, protons, electrons etc.
So, when we have the number of moles of a substance, the number of atoms is obtained by multiplying with the Avogadro's constant.
How does light emitted from a neon sign differ from sunlight?
Answer:
The light from a neon light only emits certain colors, while sunlight emits all colors.
Answer:
Well the light from a neon sign contains only a certain visible colors, while sunlight contains the full spectrum of colors. Neon sign produce emission spectrum.
Notes:
When neon atoms absorb energy and release it, its atomic emission spectrum consists of several individual lines of color. It's not a continuous range of colors, as in white light.
What are four similarities between mixtures and molecules?
Answer:The different substances in a mixture are not chemically combined, whereas the different elements in a compound are. The atoms do not combine in the mixture, but they combine when they form a compound.
Explanation:
Answer:
Explanation:
1. The constituents or components of a mixture and compound can easily be separated.
2. Both mixture and compound can be heterogeneous.
3. Both compound and mixture are combined in a definite ratio or in any proportion.
4. Both compound and mixture consist of two or more substances/elements.
5. Both compounds and mixtures have physical and chemical properties.
Hope it helped you.
A 45 min tape plays at the speed of 1.88 in/s. How long is the tape in meters?
One inch is equal to 2.54 cm.
Answer: 128.93m
Explanation:
We are told that a 45 min tape plays at the speed of 1.88 in/s. First we need to convert 45 mins to seconds. This will be: = 45 × 60 = 2700 seconds.
Therefore, the tape will use:
= 2700 × 1.88inch
= 5076 inch
Since 1 inch = 2.54cm
5076 inch = 2.54 × 5076 = 12893.04cm
Note that 100cm = 1m
We will then convert 12893.04cm to m. This will be:
= 12893.04cm / 100cm
= 128.9304m
= 128.93m
The pKa of a solution is defined by the equation pKa=-log Ka
Where Ka= acid dissociation constant.
Use the rules for logarithms and exponents to solve fo Ka in terms of pKa.
Answer:
ka = 10^-pKa
or antilog-pka
The pKa of a solution is defined by the equation pKa=-log Ka. Where Ka= acid dissociation constant. By using the rules for logarithms and exponents to solve for Ka in terms of pKa, ka = 10^-pKa or antilog -pka.
What do you mean by the term dissociation constant ?The term dissociation constant is defined as the ratio of dissociated ions to the original acid or bases in the solution. For acids, the acid dissociation constant is defined as the ratio of concentration of dissociated ions to the concentration of original acid.
The equilibrium constant is a numerical representation of an acid's strength in a solution. Ka is frequently stated in mol/L units.
To make a more administrable number, chemists define the pKa value as the negative logarithm of the Ka value as follows:
pKa = -log Ka.
Thus, By using the rules for logarithms and exponents to solve for Ka in terms of pKa, ka = 10^-pKa or antilog -pka.
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1. In what country did Celsius live, work and die
Answer:
Name - ANDERS CELSIUS
Born on 27 November 1701 Uppsala, Sweden
Died on 25 April 1744 (aged 42) Uppsala, Sweden
Nationality -Swedish
Alma mater - Uppsala University
Explanation:
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4K + O2 + 2K20
Which statement is true?
Answer:
yes 4K + O2 ------>2K20 is true.
A 100. mL sample of oxygen is heated from 320 K to 480 K at constant pressure. What is the new volume?
Answer:200ML
Explanation:from quiz ck-12
12dm3 ethene reacts with steam to make 18.4g ethanol.find the percentage yield
% yield = 74.35
Further explanationGiven
12 dm³ ethene = 12 L
18.4 g ethanol(actual)
Required
The percentage yield
Solution
Reaction
C₂H₄(g) + H₂O(g) ⇒ C₂H₅OH(g)
Assume at STP, 1 mol gas = 22.4 L
mol ethene :
= 12 L : 22.4 L
= 0.538
From equation, mol ratio C₂H₅OH : C₂H₄ = 1 : 1, so mol C₂H₅OH = 0.538
Mass Ethanol (MW=46 g/mol) ⇒ theoretical
= 0.538 x 46
= 24.748 g
% yield = (actual/theoretical) x 100%
% yield = (18.4/24.748) x 100%
% yield = 74.35
atomic radius(size)______ from left to right across a period on the periodic table
Answer:
Decreases
Explanation:
Which of the following bonds is the most polar?
a. Fr-F
b. H-f
c. Cl-F
d. I-f
e. F-F
In VSEPR theory, what information about the central atom do you need in
order to predict the shape of a molecule?
Answer:
Using the VSEPR theory, the electron bond pairs and lone pairs on the center atom will help us predict the shape of a molecule. The shape of a molecule is determined by the location of the nuclei and its electrons. The electrons and the nuclei settle into positions that minimize repulsion and maximize attraction.
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Which of the following elements would likely be a gas at rom temperature?
A. Argon (Ar)
B. Magnesium (Mg)
C. Copper (Cu)
D. 13
Answer:
A. Argon
Explanation:
it is a gas that makes up to 1% of the atmosphere
Examples of homogeneous mixtures
Answer:
air, saline solution, most alloys and bitumen
Explanation:
A body-centered cubic unit cell has an edge length of 588 pm. What is the radius of the atoms composing the unit cell?
Answer:
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Question: Describe how thermal energy
moves in a glass of ice water
(what should i write for this?)
Answer:
Explanation: The interaction between the particles of the hot water, the metal can and the cold water results in a transfer of energy outward from the hot water to the cold water. ... The mechanism in which heat is transferred from one object to another object through particle collisions is known as conduction.
A student uses a magnet to move a 0.025 kg metal ball. The magnet exerts a force of 5 N, which causes the ball to begin moving. What is the acceleration of the ball when it begins to move?
Type your answer...
Answer: The acceleration of the ball is 200 m/s².
Explanation:
Force:
Force is the push or pull on an object with mass that causes it to change velocity or to accelerate.
Force represents as a vector, which means it has both magnitude and direction.
Given:
Mass of metal ball = 0.025 kg
Force = 5 N
To Find:
Acceleration, = ?
Solution:
Formula:
How many atoms of potassium, K, are in K3PO4
Answer:
1
Explanation:
Gaseous methane reacts with gaseous oxygen gas to produce gaseous carbon dioxide and gaseous water . What is the theoretical yield of carbon dioxide formed from the reaction of 0.64g of methane and 1.1 of oxygen gas?
The theoretical yield of Carbon dioxide : 0.544 g
Further explanationGiven
0.64 g Methane
1.1 g Oxygen gas
Required
The theoretical yield of Carbon dioxide
Solution
Reaction
CH₄ + 2O₂ → CO₂ + 2H₂O.
Find limiting reactant(mol : coefficient)
mol CH₄ (MW=16 g/mol) := mass : MW
= 0.64 : 16
= 0.04
mol : coefficient = 0.04 : 1 = 0.04
mol O₂ (MW=32 g/mol) := mass : MW
= 1.1 : 32
= 0.034
mol : coefficient = 0.034 : 2 = 0.017
O₂ as a limiting reactant(smaller)
Mol CO₂ based on mol O₂
From equation, mol ratio CO₂ : O₂ = 1 : 2 , so mol CO₂ :
= 1/2 x mol O₂
= 1/2 x 0.034
= 0.017
Mass O₂ :
= 0.017 x 32 g/mol
= 0.544 g
The molar masses of four unknown gases are shown in the table. Molar Mass of Unknown GasesGas Molar Mass
A 44 g/mol
B 20 g/mol
C 30 g/mol
D 32 g/mol
Which gas is likely to have the highest rate of effusion?
Answer:
Gas B
Explanation:
because it has the lowest molar mass.
Molar Mass of Unknown Gas 20 g/mol gas is likely to have the highest rate of effusion. Option B is correct.
What is rate of effusion?The rate of effusion of a an y given gas is inversely proportional to the square root of the molar weight of the gas. The lighter the weight of a gas is, the rapidly it will effuse and the heavier the weight of the gas is, the slower one limited it will show effusion.
The effusion process of a given gas is in which a gas move from a container with the source of a hole of diameter which is smaller than the mean free path of the molecules or the molecule of gasses.
Therefore, molar Mass of Unknown Gas 20 g/mol gas is likely to have the highest rate of effusion. Option B is correct.
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4. Round off the following results to three significant figures:
a) 23.01 g
the answer should be a the the question
The lands of present-day Turkey were divided between Greece, __________, and France after the fall of the Ottoman Empire.
A.
the United Kingdom
B.
the United States
C.
Germany
D.
Italy
Please select the best answer from the choices provided
A
B
C
D
Answer:
D: Italy
Explanation:
Got it correct on EDG
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A 1.0 mol sample of He(g) at 25°C is mixed with a 1.0 mol sample of Xe(g) at 50°C. Which of the following correctly predicts the changes in average kinetic energy and the average speed of the Xe(g) atoms that will occur as the mixture approaches thermal equilibrium?
Average Speed of Xe Atoms Average Kinetic Energy of Xe Atoms
(A) Will increase Will increase
(B) Will increase Will decrease
(C) Will decrease Will increase
(D) Will decrease Will decrease
Answer:
option D.
Both the average kinetic energy and the average speed of the Xe(g) atoms that will occur as the mixture approaches thermal equilibrium will decrease.
Explanation:
Kinetic Energy is simply said to be the energy of motion, that is when an object moved from one position to another the energy that it gains is called the kinetic energy. It is represented mathematically by 1/2mv². Where m is the mass of the object and v is the velocity of the object.
The average Kinetic energy is the average of all kinetic energies of a particle. The average Kinetic energy is represented mathematically by 3/2RT.
The temperature of Xe which is at 50°C is greater that the temperature of He which is at at 25°C will decrease when it reaches equilibrium after mixing. Hence, the average kinetic energy and the average speed of the Xe(g) atoms that will occur as the mixture approaches thermal equilibrium will decrease.
THE GUILDING PRINCIPLE: We have that the average speed and KE decreases with temperature and vice versa for real gases.
Answer:
both will decrease
Explanation:
Do the substances that are reactants in a chemical reaction remain the same after the reaction is complete?
When fat comes in contact with sodium hydroxide, it produces soap and glycerin. Determine whether this is a physical change or a chemical change. Explain your
Answer: Chemical change
Explanation:
A physical change is defined as the change in which a change in shape, size takes place. No new substance gets formed in these reactions.
A chemical change is defined as the change in which a change in chemical composition takes place. A new substance is formed in these reactions.
Thus when fat comes in contact with sodium hydroxide to produce soap and glycerin, it is termed as a chemical change.
The blood cells that directly attack germs are: *
Answer:
lymphocytes
Explanation:
it consists of the b and the t cells
A student is given a sample of an unknown solid and asked to identify it. The student begins by making a list of questions to investigate about the sample.
BRAINLY QUICK!
Which question would be the least useful in helping the student identify the sample?
A) Is the sample soluble in water?
B) What is the weight of the sample?
C) Is the sample attracted to a magnet?
D) What is the melting point of the sample?
Answer:
B) What is the weight of the sample?
Explanation:
The least useful question for the student to identify the sample is "What is the weight of the sample?"
To identify a sample, it is important to know its solubility (homogenous or heterogenous), chemical properties such as melting and boiling point, and whether sample is attracted towards the magnet or not to know the nature of the sample.
Weights is the least useful characteristic of a sample that can help to identify the sample.
Hence, the correct answer is "B) What is the weight of the sample?".
