Answer:
ΔH = -470.4kJ
Explanation:
It is possible to sum 2 or more reactions to obtain the ΔH of the reaction you want to study (Hess's law). Using the reactions:
1. CaC2(s) + 2H2O(l) → C2H2(g) + Ca(OH)2(s)ΔH = −414kJ
2. 6C2H2(g) + 3CO2(g) + 4H2O(g) → 5CH2CHCO2H(g)ΔH = 132kJ
6 times the reaction 1.
6CaC2(s) + 12H2O(l) → 6C2H2(g) + 6Ca(OH)2(s)ΔH = −414kJ*6 = -2484kJ
This reaction + 2:
6CaC2(s) + 3CO2(g) + 16H2O(l) → + 6Ca(OH)2(s) + 5CH2CHCO2H(g) ΔH = -2484kJ + 132kJ = -2352kJ
As we want to calculate the net change enthalpy in the formation of just 1 mole of acrylic acid we need to divide this last reaction in 5:
6/5CaC2(s) + 3/5CO2(g) + 16/5H2O(l) → + 6/5Ca(OH)2(s) + CH2CHCO2H(g) ΔH = -2352kJ / 5
ΔH = -470.4kJThe total volume of seawater is 1.5 x 10²¹ L. Seawater contains approximately 3.5% sodium chloride by mass. At that high of a concentration of salt within the water, the density of water is 1.03 g/mL. Calculate the total mass of sodium chloride, in grams, contained in all the seawater in the world.
Answer:
There are [tex]5.408\times 10^{22}[/tex] grams contained in all the seawater in the world.
Explanation:
At first let is determinate the total mass of seawater ([tex]m_{sw}[/tex]), measured in grams, in the world by definition of density and considering that mass is distributed uniformly:
[tex]m_{sw} = \rho_{sw}\cdot V_{sw}[/tex]
Where:
[tex]\rho_{sw}[/tex] - Density of seawater, measured in grams per liters.
[tex]V_{sw}[/tex] - Volume of seawater, measured in liters.
If [tex]V_{sw} = 1.5\times 10^{21}\,L[/tex] and [tex]\rho_{sw} = 1030\,\frac{g}{L}[/tex], then:
[tex]m_{sw}=\left(1030\,\frac{g}{L} \right)\cdot (1.5\times 10^{21}\,L)[/tex]
[tex]m_{sw} = 1.545\times 10^{24}\,g[/tex]
The total mass of sodium chloride is determined by the following ratio:
[tex]r = \frac{m_{NaCl}}{m_{sw}}[/tex]
[tex]m_{NaCl} = r\cdot m_{sw}[/tex]
Given that [tex]m_{sw} = 1.545\times 10^{24}\,g[/tex] and [tex]r = 0.035[/tex], the total mass of sodium chloride in all the seawater in the world is:
[tex]m_{NaCl} = 0.035\cdot (1.545\times 10^{24}\,g)[/tex]
[tex]m_{NaCl} = 5.408\times 10^{22}\,g[/tex]
There are [tex]5.408\times 10^{22}[/tex] grams contained in all the seawater in the world.
Following are the calculation to the total mass of sodium chloride in grams:
Given:
Seawater volume[tex]= 1.5 \times 10^{21}\ L\\\\[/tex]
Seawater density [tex]= 1.03\ \frac{g}{mL}\\\\[/tex]
[tex]\%[/tex] of sodium chloride in seawater [tex]= 3.5\ \%[/tex]
To find:
The total mass of sodium chloride in grams=?
Solution:
The total volume of seawater [tex]= 1.5 \times 10^{21}\ L= 1.5 \times 10^{24}\ mL\\\\[/tex]
The density of seawater [tex]= 1.03 \frac{g}{mL}[/tex]
[tex]\therefore\\\\[/tex]
Seawater mass = Seawater volume [tex]\times[/tex] density
[tex]= 1.5 \times 10^{24}\times 1.03 \ g\\\\= 1.545 \times 10^{24}\ g\\\\[/tex]
[tex]\%[/tex] of sodium chloride in seawater [tex]= 3.5\ \%[/tex]
[tex]\therefore\\\\[/tex]
Calculating the sodium chloride mass in Seawater:
[tex]= 3.5\% \ \ of\ \ 1.545 \times 10^{24} \ g\\\\ =\frac{3.5}{100} \times 1.545 \times 10^{24}\ g\\\\= 5.4075 \times 10^{22} \ g\\\\[/tex]
Calculating the sodium chloride mass [tex]= 5.4075 \times 10^{22} \ g\\\\[/tex]
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What reasons can you give for people to pursue discoveries in chemistry?
Answer:
cure problems
pollution
purifying water
crop production
Explanation:
The reasons for people to pursue discoveries in chemistry because it is the most important part of daily life and related to the human health too.
What is chemistry?Chemistry is a field of science which deals with the chemicals present in laboratory or in our environment o related to human body also.
Their are main 3 branches of chemistry that is organic and inorganic and physical chemistry some others are too like analytical chemistry industrial chemistry pharmaceutical chemistry.
Organic chemistry deals with the carbon compounds and hydrogen compound inorganic chemistry deals with the elements of periodic table and pharmaceutical makes medicines for human health care.
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In the Chocolate Chip Rock Cycle Lab,
what was represented by stirring the
melting chips with a spatula?
B. convection currents
A. weathering
C. deposition
D. erosion
Ammonium perchlorate nh4clo4 is a powerful solid rocket fuel, used in the space shuttle boosters. it decomposes into nitrogen n2 gas, chlorine cl2 gas, oxygen o2 gas and water vapor, releasing a great deal of energy. calculate the moles of ammonium perchlorate needed to produce 1.4 of nitrogen. be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.
Answer:
Explanation:
2 NH₄ClO₄ ⇒ N₂ + Cl₂ + 2O₂ + 4 H₂O
2 moles 1 mole
We are required to produce 1.4 moles of N₂ from ammonium perchlorate .
1 mole of N₂ is produced by 2 moles of ammonium perchlorate
1.4 moles of N₂ will be produced by 2 x 1.4 = 2.8 moles of ammonium perchlorate .
Answer is 2.8 moles .
Which compound would be expected to show intense IR absorption at 2710 and 1705 cm-1? (Ph = phenyl group)
A. CH2=CHCOCH3
B. PhCHO
C. CH3COCH2CH3
D. PhCOCH3
E. CH3Cl
Answer:
B. PhCHO
Explanation:
Every organic group shows a characteristic IR absorption at certain wavelength . With the help of these absorption spectra we can identify the group present on organic molecules .
The wave number of 2710 cm⁻¹ is absorbed by aldehyde bond stretching .
The wave number of 1705 cm⁻¹ is shown by conjugated aldehyde . So the most likely compound among given compounds is PhCHO .
what has properties of both metals and nonmetals
Answer:
Metalloids.
Explanation:
they're between the metals and non metals in the periodic table
Which of the following does not involve chemical processes? A. cooking of food B.Changing of fruit color when it ripens C.Burning of Wood D.None of the above
Answer:
c because a chemical process is when something changes into another thing which the wood would be doing if you burned it
For each case below, identify the most likely value for x: a. BHx b. CHx c. NHx d. CH2Clx
Answer:
BHx, x=3
CHx, x=4
NHx, x=3
CH2Clx, x=2
Explanation:
We have to know that the value of x must depend on the valency of the central atom. If we look at each of the species;
Boron has a common valency of 3
Carbon has a common valency of 4
Nitrogen has a common valency of 3
The valency of each elements will determine the most likely value of x as outlined in the answer above.
A sample of marble has a volume of 8cm and density of 2.75g/cm. What is mass?
Answer:
22.0 g
Explanation:
To find the mass, multiply the volume by the density.
8 cm³ × 2.75 g/cm³ = 22.0 g
The marble is 22.0 g.
The human gut microbiome is a collection of microbes that are necessary for proper function of the digestive system and that contribute to the overall health of the individual. Infants are colonized with these microbes at birth and their nutrition in the early days of life is important for supporting growth of these microbes. Milk sugars are important in development of the microbiome. Which of the following best explains how both lacto-N-tetraose and lacto-N-fucopentaose could contribute to proper development of an infant's microbiome
A. Lacto-N-fucopentaose binds to surface receptors on pathogenic bacteria and prevents them from entering epithelial cells in the intestine.
B. Lacto-N-tetraose prevents pathogenic bacteria from hydrolyzing and metabolizing carbohydrates found in the intestine.
C. Lacto-N-tetraose is a food source for bacteria that aid in digestion of this and other oligosaccharides.
D. Lacto-N-fucopentaose is digested by pathogenic bacteria and, in the process, destroys these types of bacteria.
Answer:
A. Lacto-N-fucopentaose binds to surface receptors on pathogenic bacteria and prevents them from entering epithelial cells in the intestine.
C. Lacto-N-tetraose is a food source for bacteria that aid in digestion of this and other oligosaccharides.
Explanation:
Human milk contains high levels of indigestible Human milk oligosaccharides (HMOs). It is believed that these HMOs influence the process of coevolution of the nursing infant and its microbiome. Lacto-N-fucopentaose (LNFP) is a carbohydrate (i.e., an oligosaccharide) found in human milk. This oligosaccharide is a bioactive molecule that acts as a substrate for the development of the intestinal microflora. LNFP binds to proteins (to form glycoproteins) and lipids (to form glycolipids) localized on the surface of cells. Moreover, Lacto-N-tetraose (LNT) is also an oligosaccharide found in human milk, which is used as food supplement. It has been shown that LNT prevents infection by inhibiting the adhesion mechanism of harmful bacteria and their toxins. Furthermore, LNT stimulates the development of the microbiome in early life.
Which of the following statements correctly represents the relationships between molecular motion and pressure?
a. The greater the molecular motion, the less pressure the molecules exert
b.The greater the molecular motion the greater the pressure the molecules exert
c. Molecular motion is not related to the pressure the molecules exert
d. None of the above
5. A gas has a pressure of 1.26 atm and occupies a volume of 7.40 L. If the gas
compressed to a volume of 2.93 L, what will its pressure?
Answer:
0.499atm
Explanation:
The formula is
P1/V1 = P2/V2
so:
1.26atm/7.40L = P2/2.93L
then:
(1.26atm/7.40L)*2.93L = P2
= 0.4988918911atm
the answer must have 3 sig figs
In an ion with an unknown charge, the total mass of all the electrons was determined to be 1.640 x [tex]10^{-26}[/tex] g, the total mass of its protons was 4.015 x [tex]10^{-23}[/tex] g, and the total mass of its neutrons was 4.690 x [tex]10^{-23}[/tex] g. What is the identity, charge, and mass number of this ion? Electron one mass = 9.109 x [tex]10^{-31}[/tex] Proton one mass = 1.673 x [tex]10^{-27}[/tex] Neutron one mass = 1.675 x [tex]10^{-27}[/tex]
What is the specific gravity of mercury, the liquid used in thermometers, if it has a density of
13.6 g/mL?
Answer:
13.64.
Explanation:
Hello,
In this case, since the the specific gravity is computed as the ratio of the density of the given substance by the density of water that is approximately 0.997 g/mL as shown below:
[tex]s.g=\frac{\rho}{\rho _{water}}[/tex]
In such a way, for this case, we find:
[tex]s.g=\frac{13.6g/mL}{0.997g/mL}=13.64[/tex]
Which is dimensionless due the g/mL simplification.
Best regards.
The specific gravity of mercury is 13.61
Specific gravity is defined as the ratio of the density of a substance to the density of water. Mathematically;
[tex]sg=\frac{\rho_s}{\rho_{water}}[/tex]
Given the following parameters:
[tex]\rho_{Hg}=13.6g/mL\\\rho_{H_2O}=0.9998g/mL[/tex]
Substitute the given parameters into the formula;
[tex]sg=\frac{13.6g/mL}{0.9998g/mL}\\sg=13.61[/tex]
Hence the specific gravity of mercury is 13.61
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What is the empirical formula of an oxide of chromium that is 48% oxygen
Answer:
[tex]CrO_3[/tex]
Explanation:
Hello,
In this case, considering that the compound is 48% oxygen, we infer it is 52% chromium, therefore, by using their atomic masses we compute the moles by assuming those percentages as masses:
[tex]n_{Cr}=52g*\frac{1mol}{52g}=1mol\\ \\n_O=48g*\frac{1mol}{16g}=3mol[/tex]
Next, by dividing by the smallest moles, we find the subscripts in the empirical formula:
[tex]Cr=\frac{1}{1} =1\\\\O=\frac{3}{1} =3[/tex]
Which are also expressed in the smallest whole numbers, therefore the empirical formula is:
[tex]CrO_3[/tex]
Which corresponds to the chromic oxide or chromium (IV) oxide.
Regards.
The concentration of protein in a urine sample is calculated to be 2.77 μg/mL. What is the concentration of this solution in units of pounds per gallon (lb/gal)?
Answer:
The concentration of this solution in units of pounds per gallon is [tex]2.776*10^{-5} \frac{lb}{gal}[/tex]
Explanation:
Units of measurement are established models for measuring different quantities. The conversion of units is the transformation of a quantity, expressed in a certain unit of measure, into an equivalent one, which may or may not be of the same system of units.
In this case, the conversion of units is carried out knowing that 1 μg are equal to 2.205*10⁻⁹ Lb and 1 mL equals 0.00022 Gallons. So
[tex]2.77 \frac{ug}{mL} = \frac{2.77 ug}{mL}[/tex]
If 1 μg equals 2.205*10⁻⁹ lb, 2.77 μg how many lb equals?
[tex]lb=\frac{2.77ug*2.205*10^{-9}lb }{1ug}[/tex]
lb=6.10785*10⁻⁹
So, 2.77 μg= 6.10785*10⁻⁹ lb
Then:
[tex]2.77 \frac{ug}{mL} = \frac{2.77 ug}{mL}=\frac{6.10785*10^{-9}lb }{mL} =\frac{6.10785*10^{-9}lb }{0.00022 gal} =\frac{6.10785*10^{-9}lb }{0.00022 gal}[/tex]
You get:
[tex]2.77 \frac{ug}{mL} = 2.776*10^{-5} \frac{lb}{gal}[/tex]
The concentration of this solution in units of pounds per gallon is [tex]2.776*10^{-5} \frac{lb}{gal}[/tex]
please answer these true false
Answer:
False
False
they both will stay on the water
Hope this helped
How many atoms of zirconium are in 0.3521 mol of zirconium?
Answer:
2.12×10²³ atoms.
Explanation:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms. This simply means that 1 mole of zirconium also 6.02×10²³ atoms.
Thus, we can obtain the number of atoms present in 0.3521 mole of zirconium as follow:
1 mole of zirconium also 6.02×10²³ atoms.
Therefore, 0.3521 mole of zirconium will contain = 0.3521 × 6.02×10²³ = 2.12×10²³ atoms.
Therefore, 0.3521 mole of zirconium contains 2.12×10²³ atoms.
There are 2.12 × 10²³ atoms of zirconium in 0.3521 mol of zirconium.
HOW TO CALCULATE NUMBER OF ATOMS:
The number of atoms of zirconium can be calculated by multiplying the number of moles in the element with Avogadro's number. That is;no. of atoms in Zirconium = no. of moles = 6.02 × 10²³According to this question, 0.3521 mol of zirconium was given. The number of atoms can be calculated as follows:no. of atoms of Zirconium = 0.3521 × 6.02 × 10²³no. of atoms of Zirconium = 2.12 × 10²³ atoms. Therefore, there are 2.12 × 10²³ atoms of zirconium in 0.3521 mol of zirconium.Learn more at: https://brainly.com/question/15488332?referrer=searchResults
If a buffer solution is 0.260 M in a weak acid (Ka=8.3×10−5) and 0.480 M in its conjugate base, what is the pH?
Answer: pH = 4.3
Explanation: The pH of a buffer solution and its conjugate base can be determine by the Henderson-Hasselbach Equation. It can be estimated because equilibrium between weak acid and its conjugate base allows the solution to not change pH when small amounts of strong acid or base are added.
pH is calculated by:
[tex]pH = pK_{a} + log(\frac{[conjugate]}{[acid]} )[/tex]
pKa is the acidic dissociation constant and it shows how much strong an acid can be. It is determined as:
[tex]pK_{a}=-log(K_{a})[/tex]
For the buffer solution:
[tex]pK_{a}=-log(8.3.10^{-5})[/tex]
[tex]pK_{a}=4.081[/tex]
Calculating pH:
[tex]pH = 4.081 + log(\frac{0.480}{0.260} )[/tex]
[tex]pH = 4.081 + log(1.846)[/tex]
pH = 4.3
For this buffer solution and its conjugate, pH = 4.3
blance equation __CaBr2 (aq) + ___Li3PO4(aq) → ___Ca3(PO4)2(s) + ____LiBr (aq)
Answer:
3CaBr2 + 2LI3PO4 - > Ca3(PO4) 2 + 6LiBr
Explanation:
The first one I did was PO4. There are two on the right side, so I added 2 to Li3PO4 on the other side. That balanced the PO4s and then gave me 6 Lithiums so I balanced that one next on the right side. I added 6 to LiBr which balanced the Li but then gave me 6 Br, so I finished it off by adding 3 in front of CaBr2 which balanced the calcium and bromines.
Here was the process:
CaBr2+2Li3PO4 -> Ca3(PO4)2+LiBr
Balances PO4 (2on both sides)
CaBr2+2Li3PO4 -> Ca3(PO4)2+6LiBr
Balances Lithiums (6 on each side)
3CaBr2+2Li3PO4 -> Ca3(PO4)2+6LiBr
Balances Calciums and Bromines (3 Calciums and 6 Bromines each side)
Hope this helped!
What happens to the density of a material if you have a larger piece of it?(1 point) A.The density will be smaller because the mass remains the same as the volume increases.
B.The density will remain the same because mass and volume will both increase in the same way.
C. The density will remain the same because mass and volume will remain the same. D.The density will be greater because the mass increases but the volume remains the same.
PLEASSSSSSSSSSSSSE HELPPPPPPPPPPPPP ASAP.........
The change in the density of a material, if you have a larger piece of it, is the density will remain the same because mass and volume will remain the same. The correct option is C.
What is density?Density is mass per volume. It is calculated by dividing the mass by the volume of the substance. It is a scalar quantity, and it is denoted by rho a Greek symbol. Furthermore, it is written in small d.
The density, mass, and volume are related to each other. These quantities do not change with the change in the quantity of the substance. If we take the large weight or quantity of substance, the density of the substance does not change.
Thus, the correct option is C. The density will remain the same because mass and volume will remain the same.
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Initially, scientists described atoms as the smallest particles of matter. However, smaller particles within atoms were discovered. How did the scientific world respond to this new information? by ignoring the new information because it went against a scientific law by discarding the old theory about atoms and making a new one by revising the theory that explained atoms to include this new information by designing new technology that would prove the new information was wrong
Answer:
By designing new technology that would prove new information
Explanation:
im not sure about the answer but i just did the test and "by designing new technology that would prove the new information was wrong" isint the answer
Which of the following have a neutral charge. Electron, plasma, neutron, or proton
Each of these geometric shapes has adifferent number of sides. Arrange the shapes in order from theshape with the greatest number of sides to the shape with thefewest number of sides.Rank these shapes from greatest tofewest number of sides. To rank items as equivalent, overlapthem.triangle , square, rectangle, octagon, hexagon, pentagon
Answer:
Octagon > Hexagon > pentagon > square and rectangle > triangle
Explanation:
As we know that
Triangle contains 3 slides
Rectangle contains 4 slides
Square contains 4 slides
Octagon contains 8 slides
hexagon contains 6 slides
Pentagon contains 5 slides
Now based on this
The ranking is as follows
Octagon > Hexagon > pentagon > square and rectangle > triangle
This is the correct order from high to low
The diagram shows the layers formed when 10 mL each of honey, maple syrup, and corn syrup were slowly poured into a glass cylinder.
A tall cylinder with 3 layers is shown. The top layer is labeled Corn Syrup, the middle layer is labeled Maple Syrup and the bottom layer is labeled Honey.
A ping pong ball released gently into the cylinder floats on top of the corn syrup layer. What best compares the densities of the substances?
Group of answer choices
Honey is denser than corn syrup but less dense than the ball.
All liquids are denser than the ball, and honey is denser than corn syrup and maple syrup.
Corn syrup is denser than the other liquids, and the ball is denser than the liquids.
Corn syrup is denser than the other liquids and the ball.
The correct answer is B. All liquids are denser than the ball, and honey is denser than corn syrup and maple syrup.
Explanation:
Differences in density cause substances such as solids or liquids to float or sink. In general, the substance sinks if it is denser, or floats if it is less dense. In this context, honey is the substance with the most density because it is at the bottom of the container. Also, honey is followed in density by maple syrup, and then by corn syrup. Moreover, if the ping pong ball floats in the most superficial layer, it is because this is less dense than any of the liquids. According to this, it can be concluded honey is denser than the other liquids, and the liquids are denser than the ball (option B.)
Answer:
b is right ( all liquids are denser than the ball and honey is denser than corn syrup.)
Explanation:
A pure substance made up of molecules of the same kind of atoms is called...
Answer:
All substances that are made up of the same kind of mole ules are called pure substances.
So what do you mean ?
Explanation:
Answer: all matter is made up of pure substance
Explanation:
What is the mass percent of sucrose (C12H22O11, Mm = 342 g/mol) in a 0.329-m sucrose solution?
Answer:
[tex]\% m/m=10.1\%[/tex]
Explanation:
Hello,
In this case given the molal solution of sucrose, we can assume there are 0.329 moles of sucrose in 1 kg of solvent, thus, computing both the mass of sucrose and solvent in grams, we obtain:
[tex]m_{sucrose}=0.329mol*\frac{342g}{1mol}=112.5g[/tex]
[tex]m_{solvent}=1000g[/tex]
In such a way, we proceed to the calculation of the mass percent as follows:
[tex]\% m/m=\frac{112.5g}{112.5g+1000g}*100\%\\ \\\% m/m=10.1\%[/tex]
Regards.
Fe(OH)2 Spell out the full name of the compound.
Answer:
Ferrous hydroxide or iron (II) hydroxide.
Explanation:
Hello,
In this case, for the nomenclature of hydroxides we can use two styles:
a. IUPAC: it points out the oxidation state of the given metal by using suffixes ous or ic for metals having to oxidation states, thus, since +2 for iron is the first one, it turns out ferrous hydroxide.
b. Stock: it points out the oxidation state of the given metal by writing it inside parenthesis, thus, it turns out iron (II) hydroxide.
Regards.
The full name of the compound is ferrous hydroxide or iron (II) hydroxide.
Ionic compounds are formed when ions with opposing negative and positive charges form ionic bonds and form compounds, which are compounds made of ions.
Ionic compounds are named by stating the cation first, followed by the anion. When a neutral atom loses one or more electrons, it acquires a positive charge and is called a cation and when an atom gains one or more electrons, it becomes an anion and acquires a negative charge.
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The bird bobbed its head up and down.
A) qualitative
B) quantitative
"The bird bobbed its head up and down" it is qualitative. So, A is correct.
What is quantitative and qualitative?Quantitative data is numbers-based, countable, or measurable. Qualitative data is interpretation-based, descriptive, and relating to language. Quantitative data tells us how many, how much, or how often in calculations. Qualitative data can help us to understand why, how, or what happened behind certain behaviors.
That statement given in the question is not telling us about any quantity or any number, it is telling us about certain behavior.
Quantitative Information – Involves a measurable quantity—numbers are used. Some examples are length, mass, temperature, and time. Quantitative information is often called data, but can also be things other than numbers. Qualitative Information – Involves a descriptive judgment using concept words instead of numbers.
Therefore, "The bird bobbed its head up and down" it is qualitative. So, A is correct.
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Walter is observing a substance that is currently a solid. What would have to
occur for the substance to become a liquid?
Answer:
Increasing the temperature
Explanation:
Solids are usually found in low-temperature conditions. Increasing the temperature increases the energy in the solids, causing the solids to turn into a liquid state. Increasing the energy between molecules in a substance reduces the attraction force between the molecules and changes them from solid to liquid state.