Homework 2
1. A scientist is attempting to check the relative atomic masses on the periodic table. He works
with three different compounds that contain only C and another compound. These are
diatomic compounds with a formula of CX. He finds the following information. If he
assumes the weight of C is 12 what is the weight of the other element and its identity.
Wt C
Wt X
Compound 1
4.2
4.9
Compound 2 3.5
4.67
Compound 3 1.3
3.47
Answers
the concepts of mole and chemical reactions, the element of the three compounds can be found.
compound 1 carbon - Nitrogen CN
compound 2 carbon - Oxygen CO
compound 3 carbon - Sulfur CS
Chemical reactions are expressed in moles of each constituent element. The mole is one of the fundamental quantities of physics and is defined as the amount of matter in 0. 012 kg of carbon 12, in practical form the moles of a given element in a chemical reaction is found with the expression
n = m / Pm
where n is the number of moles, m the mass of the element and PM the molecular weight (taken from the periodic table) of the element.
Let's apply to our compounds as the chemical formula is CX, there is an atom of each element, let's look for the moles of carbon.
compound 1
mass of coal 4.2
carbon mole
n_C = 4.2 / 12
n_C = 0.35 mol
as in the chemical reaction there is an atom of each element, there are also 0.35 moles of the unknown element, let's find its molecular weight (PM)
PM = m / n
PM = 4.9 / 0.35
PM = 14 gr / mol
When reviewing the periodic table this weight corresponds to Nitrogen(N)
The elect is Nitrogen
compound 2
carbon mass 3.5
carbon moles
n_C = 3.5 / 12
n_C = 0.29167
moles of unknown element n = 0.29167
mass of unknown element m = 4.67
molecular weight
PM = 4.67 / 0.29167
PM = 16 gr / mol
Checking the periodic table corresponds to the element Oxygen (O)
Compound 3
carbon mass 1.3
carbon moles
n_C = 1.3 / 12
n_C = 0.1083
moles unknown element n = 0.10833
mass unknown element m = 3.47
PM = 3.47 / 0.10833
PM = 32 gr / mol
In the periodic table the element Sulfur (S) has this molecular weight
Using the concepts of mole and chemical reactions, the elements of the three compounds can be found.
compound 1 carbon - Nitrogen CN
compound 2 carbon - Oxygen CO
compound 3 carbon - Sulfur CS
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Related Questions
How many moles of oxygen atoms are there in 1 mole of Mg(NO3)2?
Answers
Answer:6 moles
Explanation: u said atoms so O₁ = 1 mole so there is a total of 6 atoms of oxygen so 6 moles is the ans.
a wooden baseball bat is an example of
a: compound
b: element
c: heterogeneous
d: homogeneous
Answers
Compound or element
A wooden baseball bat is an example of a heterogeneous substance.
A heterogeneous substance is consists of compounds that are not thoroughly mixed together.
Woods are fibrous structural substances with spaces present in trees and other woody plants' stems as well as roots. They are composed of a natural composite of cellulose fibers and are contained with a lignin matrix that is capable of resisting compression.
They can use for fire, building, the manufacture of weapons and tools, furniture, as well as paperwork.
Wood is a heterogeneous, highly porous cellular material. It is made up of cells and the cell walls are made up of roughly 40% cellulose, 15% hemicellulose, and lignin of about (15–30%).
Therefore, we can conclude that a wooden baseball bat is an example of a heterogeneous substance.
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Walter buys a bus pass for $30. Every time he rides the bus,
money is deducted from the value of the pass. He rode
12 times and $24 was deducted from the value of the pass.
How much does each bus ride cost?
Answers
Answer:
2
Explanation:
$24/12 (times) = $2.00
When multiplying 602.4 m by 3.72 m, which value determines the number of significant figures in the answer? Explain.
Answers
The values that determines the number of significant figures in the answer is 3.72
In mathematics and science, a significant figure refers to any figure that contributes to the degree of accuracy of a value that is being measured.
The value having the value having the least number of significant figures in a multiplication determines the number of significant figures in the answer.
In this case, 3.72 has the least number of significant figures hence it determines the number of significant figures in the answer.
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Answer:
3.72
Explanation:
3.72 has the least number of significant figures which means the number of significant figures is the answer.
explain the importance of the periodic table
Answers
Answer:
the importance of the periodic table are,
To summarize, the periodic table is important because it is organized to provide a great deal of information about elements and how they relate to one another in one easy-to-use reference. The table can be used to predict the properties of elements, even those that have not yet been discovered.
Explanation:
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What are the variables used in an experiment? How are they different?
Answers
Answer:
There are many items that could be altered to test the reaction of another. These changing quantities are called variables. A variable is any factor, trait, or condition that can exist in differing amounts or types. An experiment usually has three kinds of variables: independent, dependent, and controlled.
Explanation:
i need help with unit conversion
Answers
Answer:
what is it?
Explanation:
you haven't said?
What is brady's reagent, and what is it's function?
Answers
Answer:
Brady's reagent or Borche's reagent, is prepared by dissolving 2,4-dinitrophenylhydrazine in a solution containing methanol and some concentrated sulfuric acid. This solution is used to detect ketones and aldehydes.
Answer:
It is 2,4-dinitrophenylhydrazine, it confirms presence of a carbonyl functional group [ hydrazine and ketone ]
Explanation:
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phillip morris cigaretteshave 5mg tar and 0.4 mg nicotine per cigarette and 20 cigarettes per pack how many packs of cigarettes would have to be smoked to coat your lungs with 4.0 oz (1/4 lb) of tar? How many packs of cigarettes would have to be smoked to introduce your lungs to one gram of nicotine?
Answers
Answer: A solution is made by dissolving 27.8 g of nicotine (Molar Mass = 160 g/mol) in 145 g of cyclohexane (C6H12) to form 142 mL of solution. Calculate the mole fraction of the solute and the molarity, respectively, of this solution.
Explanation:
Sterling silver is 92.5% silver and 7.5% copper. Its density is 10.25 g/cm3. A sterling silver pendant is added to a graduated cylinder filled with 50.0 mL of water. The volume rises to 61.3 mL. What is the mass of copper contained in this pendant?
Answers
From the information given:
The volume of the graduated cylinder = 50.0 mLwhen a sterling silver pendant is added, the volume increases to = 61.3 mL∴
The volume of the sterling silver pendant is:
= 61.3 mL - 50.0 mL
= 11.3 mL
Since, 1 mL = 1cm³
Then;
11.3 mL = 11.3 cm³
the density of the sterling silver = 10.25 g/cm³Using the relation for Density; i.e.
[tex]\mathbf{Density = \dfrac{mass}{volume}}[/tex]
[tex]\mathbf{10.25 \ g/cm^3= \dfrac{mass}{11.3 \ cm^3}}[/tex]
mass = 10.25 g/cm³× 11.3 cm³
mass of the sterling silver = 115.825 grams
Recall that sterling silver has:
92.5% silver and;7.5% copper∴
The mass of the copper contained in the sterling silver pendant can be calculated as:
[tex]\mathbf{= \dfrac{115.825 \ g \times 7.5}{100}}[/tex]
= 8.687 grams
Therefore, we can conclude that the mass of the copper contained in the sterling silver pendant is 8.687 grams
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A pycnometer is a glass apparatus used for accurately determining the density of a liquid. When dry and empty, a certain pycnometer had a mass of 27.056 g. When filled with distilled water at 25.0°C, it weighed 36.773 g. When filled with chloroform (a liquid once used as an anesthetic before its toxic properties were known), the apparatus weighed 41.451 g. At 25.0°C, the density of water is 0.99704 g/mL
Answers
Complete Question
A pycnometer is a glass apparatus used for accurately determining the density of a liquid. When dry and empty, a certain pycnometer had a mass of 27.056 g. When filled with distilled water at 25.0°C, it weighed 36.773 g. When filled with chloroform (a liquid once used as an anesthetic before its toxic properties were known), the apparatus weighed 41.451 g. At 25.0°C, the density of water is 0.99704 g/mL
-What is the volume of the pycnometer (mL)
We have that the volume of the pycnometer in mL is
[tex]V=9.111mL[/tex]
From the Question we are told that
Pycnometer mass of [tex]m_p=27.056 g.[/tex]
Temperature [tex]T=25 \textdegree[/tex]
Pycnometer filled with distilled water [tex]m_{pf}= 36.773 g[/tex]
Apparatus weighed [tex]w=41.451 g[/tex]
Density of water [tex]\rho= 0.99704 g/mL[/tex]
Generally the equation for Density is mathematically given as
[tex]\rho=\frac{mass}{Volume}[/tex]
Since pycnometer is filled with water its volume can be defined by the volume of water in it
Therefore
Mass of water Pycnometer filled with distilled water-Pycnometer mass
[tex]M_w=36.773 -27.056\\\\M_w=9.084g[/tex]
Hence
[tex]V=\frac{9.084g}{0.99704 }[/tex]
[tex]V=9.111mL[/tex]
in conclusion
The volume of the Pycnometer in mL is
[tex]V=9.111mL[/tex]
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Please help me please find the answer
Please do this
Please do this
Plzz
Plzz
Answers
Total distance=60m+40m=100m
Total Time=6+4=10s
#a
[tex]\boxed{\sf Speed=\dfrac{Distance}{Time}}[/tex]
[tex]\\ \sf\longmapsto Speed=\dfrac{100}{10}[/tex]
[tex]\\ \sf\longmapsto 10m/s[/tex]
#b
Displacement=AC=60m
[tex]\\ \sf\longmapsto Velocity=\dfrac{Displacement}{Time}[/tex]
[tex]\\ \sf\longmapsto Velocity=\dfrac{60}{10}[/tex]
[tex]\\ \sf\longmapsto 6m/s[/tex]
#C
Distance=60m
time=5s
[tex]\\ \sf\longmapsto Velocity=\dfrac{60}{5}=12m/s[/tex]
#d
The velocity of A to C is greater than Velocity from C to A
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The atomic radii of elements on the periodic table generally _______ from left to right and _______ from top to bottom.
A.
increase; decrease
B.
decrease; increase
C.
stay the same; increase
D.
increase; increase
Answers
Hey there! Here is the answer:
B.) decrease; increase
Here's why:
As you move from left to right across a period on the periodic table the size of an atom will decrease. As you move from top to bottom down a group on the periodic table the size of an atom will increase.
I really hope this answer helps you out! :)
How can constraints be used to help define the problem?
Answers
Answer: Constraints are restrictions (limitations, boundaries) that need to be placed upon variables used in equations that model real-world situations. It is possible that certain solutions which make an equation true mathematically, may not make any sense in the context of a real-world word problem.
Explanation:
Constraints is a condition which helps in optimization that solution satisfies.
What are constraints?Constraints are logical conditions that solution to a problem of optimization must satisfy.In defining constraint, value of interest is computed using variables of decision.
There are 5 types of constraints:
1) NOT NULL constraints- They prevent null values to be entered.
2) unique constraints-ensures that each value is different from others and is not null.
3) Check constraints-It is a database rule specifying values in one or more columns.
4) foreign key constraints- It gives definition of required relationships between and within tables.
5) informative constraints-It is a constraint which is used by the SQL compiler for improving access to the data.
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plz do this i need help ill give u brailiest
Answers
1. C
2. B
3. B
4. sorry, but we cant see the pictures. thats all I can do.
-Chad
Answer:
(1) Turgor, an internalstimulus, refers to energy in a plant cell.
(2) Osmosis moves materials in and out of the plant cell from areas of low to high concentration?
(3) When a plant is hypertonic,what is happening in the plantcell, and what will the plantlook like?
→ A. The vacuole is not full and the plant is wilted.
(4) What picture at the bottom of the page represents equilibrium orbalance in a cell?
→ Sorry the picture is not given
Someone answer this tysm
Answers
Answer:
D: The energy of objects that are moving
Answer:
The energy of objects that are moving.
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What is the most stable element in the universe (in terms of binding energy)?
A. uranium
B. gold
C. iron
D. hydrogen
E. helium
F. lead
G. water
Answers
Answer:
C).Iron
Explanation:
Iron has a binding energy of 8.8MeV
What is the rate law?
Answers
Answer: B
Explanation:
The rate law is the mathematical equation that describes how reactant concentration changes as a function of time. A law such as "Rate = k*[A]*[B]" means that, for each liter-equivalent of the reactant(s) A, there are k liters of reactant B. The law also dictates the molarity (and thus partial pressure) for each component in solution.
For most of a star's life it will use this element for it's fuel. just 1 answer
Answers
Explanation
In the laboratory you dissolve 19.4 g of sodium chloride in a volumetric flask
and add water to a total volume of 375 mL.
What is the molarity of the solution? In M. What is the concentration of the sodium cation? In M. What is the concentration of the chloride anion? In M.
Answers
Answer: 0.885 M
Explanation: 19.4 grams of NaCl is (19.4g/58.55 g/mole) = 0.332 moles of NaCl. 375ml is 0.375 liters. Molar is moles per liter: (0.332 moles NaCl/0.375 liters) = 0.885 M
HELP! 100 points if you give a valid answer and brainliest if it's detailed!
Answers
Explanation:
The extract of plant is not done in fixed proportion
it is heterogeneous
heterogeneous mixture homogeneous
How are they similar?
Answers
Answer:
By definition, a pure substance or a homogeneous mixture consists of a single phase. A heterogeneous mixture consists of two or more phases. When oil and water are combined, they do not mix evenly, but instead form two separate layers. Each of the layers is called a phase.
Explanation:
What units do you use to measure mass?
inches
feet
milliliter
gram or kilogram
Answers
Answer:
gram or kilogram
Explanation:
these are the only ways for mass of the options
Answer:
unit of the mass is kilogram that the answer
Example of movable and fixed pully.
Answers
Answer:
A good example of a fixed pulley is a flag pole: When you pull down on the rope, the direction of force is redirected by the pulley, and you raise the flag. ... Examples of movable pulleys include construction cranes, modern elevators, and some types of weight lifting machines at the gym.The steps in every scientific investigation must_______________________.
A. follow exactly the same sequence.
B. begin with a hypothesis
C. include the development of a theory.
D. be performed in a logical sequence.
Answers
Answer:
B. begin with a hypothesis
Explanation:
How do you Convert 312 kelvin too 100 Fahrenheit?
Answers
ºF = 1.8 x (K - 273) + 32.
So first you’d subtract whatever kelvin you had and 273 so:
312-273=39
and then you’d take that answer and multiple by 1.8
39x1.8=70.2
and then you add 32 to your answer
70.2+32= 102.2 fahrenheit
Many familiar substances have common, unsystematic names. For each of the following, give the correct systematic name:
(a) saltpeter, KNO3;
(b) soda ash, Na2CO3;
(c) lime, CaO;
(d) muriatic acid, HCl;
(e) Epsom salts, MgSO4;
(f) milk of magnesia, Mg(OH)2
Answers
b) sodium carbonate
c) calcium oxide
d) hydrogen chloride (hydrochloric acid)
e) magnesium sulfate
d) magnesium hydroxide
why do you have to pay for everthing it should be free for new user for like a week
Answers
How many moles are in 237.7 g of Ba(OH)2? Answer in units of mol.
Answers
Answer: 1.387 moles Ba(OH)2
Explanation: Molar mass of Ba(OH)2 is 171.3 grams/mole
(237.7 grams)/(171.3 grams/mole) = 1.3876 moles
How much of Earth's fresh water is stored in the cryosphere?
O A. 1/6
B. 1/2
C. 9/10
OD. 2/3
Reset Selection
Answers
Answer:
1/6
Explanation:
Because cryosphere does not much water
