What can rocks tell paleoclimatologists about Earth’s atmosphere at the time that the rock was forming?
A coffee cup calorimeter contains 100.0 mL of 1.50 M Ba(NO3)2 at 25.0o C. A student pours 100.0 mL of 1.50 M Na2SO4 at 25.0o C into the calorimeter. A precipitate forms and the temperature rises to 29.7o C. Assume that no heat was lost to the surroundings, the volumes were additive, the specific heat capacity of the solution was 4.184 J/gK, and the density of the solution was 1.00 g/mL.
A. This reaction could be represented as a complete ionic or a net ionic equation. Write the balanced chemical equation that should be used in association with the Delta Hrxn value for this reaction.
B. Find the amount of heat that was lost or gained by the solution in the calorimeter.
C. Find the heat of reaction, Delta Hrxn.
D. Is the reaction endothermic or exothermic?
Answer:
Ba(NO₃)₂ + Na₂SO₄ → BaSO₄ + 2NaNO₃
q = 3.93 kJ
ΔH_{rxn} = 26.2 kJ/mole
Exothermic
Explanation:
Given that:
The Volume of Ba (NO₃)₂ = 100.0 mL
The molarity of Ba (NO₃)₂ = 1.50 M
The volume of Na₂SO₄ = 100.0 mL
The molarity of Na₂SO₄ = 1.50 M
From the above, the total volume of solution = 200.0 mL
Density of solution = 1 g/mL
The balanced equation can be written as:
Ba(NO₃)₂ + Na₂SO₄ → BaSO₄ + 2NaNO₃
We know that:
Density = mass/volume
Thus;
the mass of the solution = density × volume
= 200 × 1
= 200 g
Temperature change ΔT = T₂ - T₁
ΔT = (29.7 - 25)° C
ΔT = 4.7° C
Heat capacity c = 4.184 J/gK
∴
The amount of heat lost or gained q = m× c×ΔT
q = 200 × 4.184 × 4.7
q = 3932.96 J
q = 3.93 kJ
From the above information, we can determine the number of moles of Ba(NO₃)₂ and Na₂SO₄
For Ba(NO₃)₂
number of moles = 0.10 × 1.50
= 0.15
For Na₂SO₄
number of moles = 0.10 × 1.50
= 0.15
∴
ΔH_{rxn} = q/number of moles
ΔH_{rxn} = 3.93/0.15
ΔH_{rxn} = 26.2 kJ/mole
From the reaction, we will notice that the temperature increased. This significantly implies that heat is evolved from the reaction. As such, the reaction is exothermic.
9. What metric unit would be most
appropriate to use when measuring
the length of a paperclip?
a. Millimeter
b. Decimeter
c. Meter
d. Kilometer
Answer: a. Millimeter
Explanation:
A paperclip is a small device or instrument that can be used to hold the papers or stack of papers together. The length of the paperclip can be measured using millimeter. It is equal to the thousands of meters. The millimeter is a dimension which is used to measure the very small length objects which have visible scale distances and length.
Decimeter can be used to measure the length of the object smaller than paperclips. Meter and kilometers are used for objects and distances larger than paperclip.
What's the purpose of electro cleaning by using electrolysis?
Answer:
Electrolytic cleaning is a method of removing soil, scale or corrosion products from a metal surface by subjecting it as an electrode to an electric current in an electrolytic bath. It is a form of electroplating that can be applied to all electric conductive materials.
Esters are formed from the reaction of an alcohol and a carboxylic acid. Identify the alcohol and carboxylic acid combination necessary to make each pictured ester.
Answer:
In this practical, students explore the formation of esters through the ability of different alcohols to react with organic acids. Together, the class can quickly produce a range of esters on a test tube scale, with a variety of interesting smells to sample and compare
The pictured ester can be prepared by the combination of ethanol and propionic Acid. The name of the ester in the picture will be ethyl propanoate.
What are esters?Chemicals called esters are created when an oxoacid reacts with a hydroxyl molecule, such as alcohol or phenol. Esters are widely used. The fatty acid esters of glycerol are the majority of naturally occurring fats and oils.
When an ester reacts with either an amine or alcohol, the reaction is referred to as aminolysis; when an ester reacts with water, it is referred to as hydrolysis of ester. Esters are primarily utilized in flavorings and fragrances, but they can also be employed as solvents in the chemical industry.
Therefore, ethanol and propionic acid can be combined to create the ester shown.
To learn more about esters, refer to the link:
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The question is incomplete. Your most probably complete question is given below:
The image of the ester is attached below
8. How many moles of carbon dioxide are there in 52.06 g of carbon dioxide?
A) 0.8452
B) 1.183
C) 6.022 x 1023
D) 8.648 x 1023
E) 3.134 x 1025
Answer:
B) 1.183
Explanation:
To convert from grams (mass) to moles, we need to divide by the atomic mass (amu)..
The amu of [tex]CO_{2}[/tex] is 44.008
52.06/44.08 = 1.182966733
This can be rounded to 1.1830 moles of CO2
1.183 moles of carbon dioxide are there in 52.06 g of carbon dioxide.
Explanation:
Moles of substance are defined ratio of the given mass of the substance to the molar mass of the substance.Given :
The 52.06 grams of carbon dioxide.
To find :
The moles of carbon dioxide.
Solution:
The mass of carbon dioxide = 52.06 g
The molar mass of carbon dioxide = 44.01 g/mol
The moles of carbon dioxide:
[tex]=\frac{52.06 g}{44.01 g/mol}=1.183 mol[/tex]
1.183 moles of carbon dioxide are there in 52.06 g of carbon dioxide.
Learn more about the number of moles here:
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Which of the following has the strongest hydrogen bonds?
Group of answer choices
C2H6
HF
CH4
H2Se
Answer:
first and the last one hope this helps
Explanation:
How many atoms are present in 0.035 moles?
Answer:
[tex]2.11x10^{22}atoms[/tex]
Explanation:
Hello!
In this case, considering the Avogadro's number, which relates the number of particles and one mole, we can infer that 1 mole of any element contains 6.022x10²³ atoms as shown below:
[tex]\frac{6.022x10^{23}atoms}{1mol}[/tex]
Thus, we compute the number of atoms in 0.035 moles as shown below:
[tex]atoms=0.035mol*\frac{6.022x10^{23}atoms}{1mol} \\\\atoms=2.11x10^{22}atoms[/tex]
Best regards!
A .......... notifies you that danger is present if the directions are not followed.
•A . Warning
•B.Hazard
•C. Safety
•D. Danger
Answer:
A. Warning
Explanation:
Out of all said choices, the best choice would be warning since it would fit the sentence the most.
"A Warning notifies you that danger is present." compared to:
"A Hazard notifies you that danger is present."
"A Safety notifies you that danger is present."
"A Danger notifies you that danger is present."
CHEMISTRY H E L P
In the following chemical reaction, what reactant is represented by X? AlCl₃ + X → Al(OH)₃ + NaCl
A) NaOH
B) ClOH
C) Al(OH)
D) It cannot be determined.
Answer: NAOH
Explanation:
which mineral is composed of calcium and fluorine?
Answer:
Fluorite
What is Fluorite? Fluorite is an important industrial mineral composed of calcium and fluorine (CaF2). It is used in a wide variety of chemical, metallurgical, and ceramic processes
How many lead atoms in Pb(OH) 4 ?
4 in hydrogen 4 in oxygen
Explanation:
hope this helps
name all nonmetals that are noble has.
PLEASE HELP ASAP ILL GIVE YOU BRAINLIEST
What do most mollusks have?
C
Answer:
C- A foot
Particularly a muscular foot.
Answer/Explanation
you"re right they have a foot
Muscular foot for creeping or burrowing. Some also have a head with sense organs.
did u need someone to confirm it or what
Which chemical equation is unbalanced?
C + O2 Right arrow. CO2
Sr + O2 Right arrow. 2SrO
6H2 + 3O2 Right arrow. 6H2O
H2 + H2 + O2 Right arrow. H2O + H2O
Answer:
Sr + 02 Right arrow.2Sr0
Answer:
b
Explanation:
Increasing the force on an object _________ its acceleration, if the mass of the object stays the same
Why do balls bounce higher on hard floors than on carpet?
a) They don't. That is a myth.
b) The carpet friction creates thermal energy.
c) The carpet fibers attract the molecules in the ball.
d)The carpet is so nice and soft the ball doesn't want to go.
Answer:
I'm pretty sure c......
Answer is B
The friction causes the ball to lose energy on carpets, which makes the ball bounce less. On hard floors, not as much thermal energy is lost, which is why it bounces higher.
How many moles of NaCl are created as a result of decomposing 12 grams of NaClO3? (molar mass of Na=23, Cl=35, O=16)
Answer: 0.113 moles of NaCl are created as a result of decomposing 12 grams of [tex]NaClO_3[/tex].
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} NaClO_3=\frac{12g}{106.5g/mol}=0.113moles[/tex]
The balanced chemical equation for decomposition of [tex]NaClO_3[/tex] is:
[tex]2NaClO_3\rightarrow 2NaCl+3O_2[/tex]
According to stoichiometry :
2 moles of [tex]NaClO_3[/tex] give = 2 moles of [tex]NaCl[/tex]
Thus 0.113 moles of [tex]NaClO_3[/tex] give =[tex]\frac{2}{2}\times 0.113=0.113moles[/tex] of [tex]NaCl[/tex]
Thus 0.113 moles of NaCl are created as a result of decomposing 12 grams of [tex]NaClO_3[/tex].
What is the chemical formula for Sulfuric acid
Answer:
H₂SO₄
have a great day
Answer:
Explanation:
The chemical formula for Sulfuric acid is H₂SO₄
Isopropanol burns in oxygen to yield carbon dioxide, water, and heat. Which word equation best represents this chemical reaction?
isopropanol Right arrow. carbon dioxide + water + heat
isopropanol Right arrow. carbon dioxide + water + oxygen
isopropanol + oxygen Right arrow. carbon dioxide + water + heat
isopropanol + oxygen + heat Right arrow. carbon dioxide + water
Answer:
isopropanol + oxygen Right arrow. carbon dioxide + water + heat
Explanation:
Word equation:
isopropanol + oxygen → carbon dioxide + water + heat
Chemical equation:
2C₃H₇OH + 9O₂ → 6CO₂ + 8H₂O + Heat
The given reaction is combustion of isopropanol. Isopropanol burn in the presence of oxygen and produced carbon dioxide and water. Heat is also produced in this reaction.
The given reaction also follow the law of conservation of mass. There are equal number of moles of each element on both side of reaction equation thus mass remain conserved.
isopropanol + oxygen Right arrow. carbon dioxide + water + heat
The following information should be considered:
Word equation:
isopropanol + oxygen → carbon dioxide + water + heat
Chemical equation:
[tex]2C_3H_7OH + 9O_2 \rightarrow 6CO_2 + 8H_2O + Heat[/tex]
The given reaction is combustion of isopropanol. Isopropanol should be burn with the presence of oxygen and generated carbon dioxide and water. Heat is also generated in this reaction. The given reaction also follows the law of conservation of mass
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Questlon 23 of 30
What is the term for a large group of people with similar characteristics such
as educational background and income level?
A. An interest group
B. A social class
C. A social culture
O D. A political party
SUBMIT
what is the mass in grams of 0.40 moles of sodium borohydride nabh4
Answer:
15.12g
Explanation:
Given parameters:
Number of moles = 0.4moles
Unknown:
Mass of the compound = ?
Solution:
To solve this problem;
Mass = number of moles x molar mass
Molar mass of NaBH₄ = 23 + 10.8 + 4(1) = 37.8g/mol
Mass of the compound = 0.4 x 37.8 = 15.12g
Answer:
The answer is 15.12 g but if you are taking this test on ck12 make sure you round it to 15 like it says on the directions :) good luck
Many organisms on Earth exhibit similar ____________.
Question 1 options:
time
single-celled
characteristics
nonliving
Answer:
characteristics
Explanation:
i promise becasue i am a teacher so i hope you like it
What is the ratio of hydrogen atoms to oxygen atoms in a water molecule?
number the steps for balancing equations:
O Use coefficients to increase the atoms on each side.
O Check to make sure you have the same number of each type of atom on each side.
O Count the atoms on each side.
O Identify the atoms on each side.
Explanation:
In balancing chemical equations, the law of conservation of matter must be strictly obeyed.
By the virtue of this, the following steps are usually taken:
First identify the atoms on each side of the expression. This to know the number of species to balance. Then count the atoms on each side. Then using appropriate number as the coefficients, increase the atom on each side until there are equal numbers on both sides. Finally, check to make sure we have the same number of each type of atom on each side.Answer:
the answer would be 3 4 2 1
Explanation:
A 0.500-gram sample of a weak, nonvolatile monoprotic acid, HA, was dissolved in sufficient water to make 50.0 milliliters of solution. The solution was then titrated with a standard NaOH solution. Predict how the calculated molar mass of HA would be affected (too high, too low, or not affected by the following laboratory procedures. Explain each of your answers.
a. After rinsing the buret with distilled water, the buret is filled with the standard NaOH solution; the weak acid HA is titrated to its equivalence point.
b. Extra water is added to the 0.500-gram sample of HA.
(a) An indicator that changes color at pH 5 is used to signal the equivalence point.
(b) An air bubble passes unnoticed through the tip of the buret during the titration.
Answer:
Follows are the solution to the given points:
Explanation:
It is expected to be too low a calculated molecular weight. It is because NaOH is diluted throughout washing with distilled water. It means that its measured intensity would be too high. Mwt implies Mwt now. Oh, Mwt. It's low. If the water becomes inserted throughout the acid HA, the molarity Across would not be impacted as the acidic mole remains unchanged despite water added to the acidic Ha. It's going to be much too big a molecular weight. Its measurement indicates the middle state at PH=5, well before this neutral point, so that if the NaOH reading is less, and the value of the strength of HA would consequently become lower. So m/Mwt=low shows Mwt=high.Its real measurement will be less because of the air pocket in the office. Even so, because of an unknown bubble interpretation, more is removed. Its intensity of acid is, therefore, less measured, and thus Mwt is also too high.\ helppppp
Many organisms on Earth exhibit similar ____________.
Question 2 options:
nonliving
characteristics
time
single-celled
Answer:
characteristics i believe
. What were the main inventions of the industrial revolution? What changes did they bring about ?
Answer:
The Industrial Revolution was a period of great industrialization that began in the late 18th century in Britain, leading to massive population growth and agricultural innovations, which laid the foundation for increased productivity, both with increased labor and a larger market for the products. There was a revolution in the production methods of the textile industry, especially with the advent of the steam engine and urban development, the influx of people from the countryside to the cities meant that there was an abundance of labor, which laid the foundation for the industrial cities of the nineteenth century. The steam engine was also used in the new generation of transport, in locomotives and steamships. With the advent of steel as a building material along with a series of new discoveries in communication technology in the second half of the 19th century, the tone was set for the continued technological development of the 20th century.
PLEASE HELP WHICH ONE IS IT AND CAN YOU EXPLAN HOW YOU GOT THE ANSWERS TY!!!
In a titration, a 20 mL sample of NaOH(aq) was neutralized by 14.9 mL of 0.13 mol/L
H2SO4(aq). The concentration of the base is
A)8.7 mol/L
B)10.048 mol/L
C)0.19 mol/L
D)0.35 mol/L
/L
Answer:
C)0.19 mol/L .
Explanation:
Hello!
In this case, since the chemical reaction between sodium hydroxide and sulfuric acid is:
[tex]H_2SO_4+2NaOH\rightarrow Na_2SO_4+2H_2O[/tex]
Whereas a 1:2 mole ratio is seen between the acid and the base, we can write:
[tex]2*M_{acid}V_{acid}=M_{base}V_{base}[/tex]
In such a way, we solve for the concentration of base and plug in to obtain:
[tex]M_{base}=\frac{2*M_{acid}V_{acid}}{V_{base}} \\\\M_{base}=\frac{2*0.13mol/L*14.9mL}{20mL} \\\\M_{base}=0.19mol/L[/tex]
Thus, the answer is C)0.19 mol/L
Best regards!
What is MnF3 + AL ? If anyone would
Be so kind