Answer:
I would interpret the statement by using a formula.
Explanation:
In order to be scientifical in a research, the scientific method must be used, this means that in this case, Lavoisier should´ve follow a Hypothesis, Objectives, a Methodlogy, Results and made a Discussion and Conclusion.
To prove that the mass gained by the pipe plus the mass of the collected gas "exactly" equaled the lost mass of water, Lavoisier should´ve used this statement as a formula where it proves with numbers that is correct.
For example:
mg= mass gained by the pipe
mc=mass of the collected gas
ml=lost mass of water
mg+mc=ml
An ideal diatomic gas starting at room temperature T1 = 300 K and atmospheric pressure p1 = 1.0 atm is compressed adiabatically to 1/10 of its original volume. What is the final temperature of the gas?
Answer:
The final temperature of the given ideal diatomic gas: T₂ = 753.6 K
Explanation:
Given: Atmospheric pressure: P = 1.0 atm
Initial Volume: V₁ , Final Volume: V₂ = V₁ (1/10)
⇒ V₁ / V₂ = 10
Initial Temperature: T₁ = 300 K, Final temperature: T₂ = ? K
For a diatomic ideal gas: γ = 7/5
For an adiabatic process:
[tex]V^{\gamma-1 }T = constant[/tex]
[tex]V_{1}^{\gamma-1 }T_{1} = V_{2}^{\gamma-1 }T_{2}[/tex]
[tex]\left [\frac{V_{1}}{V_{2}} \right ]^{\gamma-1 } = \frac{T_{2}}{T_{1}}[/tex]
[tex]\left [10 \right ]^{\frac{7}{5}-1 } = \frac{T_{2}}{300 K}[/tex]
[tex]\left [10 \right ]^{\frac{2}{5} } = \frac{T_{2}}{300 K}[/tex]
[tex]2.512 = \frac{T_{2}}{300 K}[/tex]
[tex]T_{2} = 753.6 K[/tex]
Therefore, the final temperature of the given ideal diatomic gas: T₂ = 753.6 K
Consider two solutions separated by a semi permeable membrane. The membrane allows the passage of small molecules and ions, but not large molecules like polysaccharides are proteins. Solution A contains a 10% solution composed of glucose and the protein albumin dissolved in water. Solution B contains a 5% solution of NaCl in water. Indicate whether each substance in the system would flow into Solution A, Solution B, or neither.
a. Water:
b. NaCl:
c. Albumin:
d. Glucose:
i would saythat the answer would be D
An ionic compound is formed when there is a reaction between the elements
Ionic compounds are formed when a metal and a nonmetal react, leading to a transfer of electrons and the formation of ions. These ions are held together by ionic bonds, which demonstrate strong electrostatic attraction. These compounds display unique properties, including high melting and boiling points, and they can conduct electricity when dissolved or melted.
Explanation:An ionic compound is formed when an element composed of atoms that readily lose electrons (a metal) reacts with an element composed of atoms that readily gain electrons (a nonmetal). This process usually leads to a transfer of electrons, resulting in the production of ions. For example, sodium atoms can lose an electron to form positively charged sodium ions (Na+), while chlorine atoms can gain an electron to form negatively charged chloride ions (Cl-). A compound such as NaCl consists of these sodium and chloride ions held together by ionic bonds — the electrostatic attractions between oppositely charged ions.
Ionic compounds have certain distinct properties. They exhibit a crystalline structure and are usually rigid and brittle. Their melting and boiling points tend to be high, implying the strength of the ionic bonds. These compounds are poor conductors of electricity in their solid state due to the immobility of ions, but once dissolved or melted, they become excellent conductors because the ions are free to move.
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What is the molarity of a potassium triiodide solution, KI3(aq), if 30.00 mL of the solution is required to completely react with 25.00 mL of a 0.300 M thiosulfate solution, K2S2O3(aq)? The chemical equation for the reaction is 2 S2O32-(aq) + I3-(aq) → S4O62-(aq) + 3 I-(aq).
Answer:
Molarity of triiodide solution is 0.125M
Explanation:
According to balanced equation, 2 moles of [tex]S_{2}O_{3}^{2-}[/tex] completely react with 1 mol of [tex]I_{3}^{-}[/tex].
Moles of [tex]S_{2}O_{3}^{2-}[/tex] in 25.00 mL of 0.300 M of [tex]K_{2}S_{2}O_{3}[/tex] solution = [tex](0.300\times 0.02500)moles=0.0075moles[/tex]
So, 0.0075 moles of [tex]S_{2}O_{3}^{2-}[/tex] completely reacts with [tex](\frac{1}{2}\times 0.0075)moles[/tex] of [tex]I_{3}^{-}[/tex] or 0.00375 moles of [tex]I_{3}^{-}[/tex]
If molarity of [tex]KI_{3}[/tex] solution is S (M) then-
[tex]S\times 0.0300=0.00375[/tex]
or, [tex]S=0.125[/tex]
So, molarity of triiodide solution is 0.125M
To determine the molarity of the KI3 solution, calculate the moles of S2O32- that reacted and use the stoichiometry of the reaction to find the moles of I3-. Then, divide the moles of I3- by the volume of KI3 solution in liters to find the molarity.
Explanation:The question asks for the molarity of a potassium triiodide (KI3) solution. To find the molarity of the KI3(aq) solution, we need to use the provided stoichiometry of the reaction between thiosulfate (S2O32-) and triiodide (I3-).
The reaction is given as: 2 S2O32-(aq) + I3-(aq) → S4O62-(aq) + 3 I-(aq). Since 25.00 mL of a 0.300 M thiosulfate solution is required to completely react with the KI3 solution, we first calculate the moles of S2O32- reacted.
Moles of S2O32- = 0.025 L * 0.300 mol/L = 0.0075 moles.
According to the balanced equation, 1 mole of I3- reacts with 2 moles of S2O32-. Therefore, we have:
Moles of I3- = 0.0075 moles S2O32- / 2 = 0.00375 moles.
Because 30.00 mL (or 0.03000 L) of KI3 solution contains 0.00375 moles I3-, the molarity of KI3 is calculated by:
Molarity of KI3 = 0.00375 moles / 0.03000 L = 0.125 M.
Organic compounds are distinguished by molecules that contain ________ bonded to other elements.
As atoms gain energy, they move faster and slide past one another more easily. Atoms at the surface of the substance overcome attractions to nearby atoms and break free of the surface. Which change of state is taking place?
- liquid to gas
- gas to liquid
- liquid to solid
- solid to liquid
Answer:
Liquid to gas
Explanation:
There are three states of matter, the solid, liquid and gaseous states. These states can be compared in a number of ways. These comparisms would tell us that the molecules of gases have the highest mobility.
The freedom possessed by these molecules are as a result of there inherent kinetic energy. While we have the highest confinement for solids, molecules of solids still have a level of freedom and hence although confined can move in some directions but are not entirely free from the total confinement of intermolecular forces like solids.
Hence,this total freedom is a character of gaseous molecules. As we were made to know in the question that they already had exhibited degree of movement to an extent,the total breakaway is to the gaseous state.
Thus,the phase transition is from liquid to gaseous state.
Vaporization (evaporation) is the transition from liquid to gas as atoms gain energy, break free of surface attractions, and move freely.
Vaporization (evaporation) is the change of state taking place when atoms at the surface of a substance absorb energy, overcome attractions to nearby atoms, and break free of the surface, transitioning from liquid to gas. This process involves the absorption of energy, which allows particles to move freely and transition into the gas phase.
A gas mixture used for anesthesia contains 2.83 mol oxygen (O2), and 8.41 mol of nitrous oxide (N2O). The total pressure of the mixture is 192 kPa. What is the partial pressure of N2O? Report your answer with three significant figures.
Answer:
The partial pressure of N2O is 143.6 kPa
Explanation:
Step 1: Data given
Moles O2 = 2.83 mol
Moles N2O = 8.41 mol
Total pressure = 192 kPa
Step 2: Calculate total number of moles
Total numberof moles = moles O2 + molesN2O = 2.83 + 8.41 = 11.24 mol
Step 3: Calculate mole fraction of N2O
Mole fraction N2O = mole N2O / Total moles
Mole fraction N2O = 8.41 / 11.24 = 0.748
Step 4: Calculate partial pressure of N2O
pN2O = 0.748 * 192 kPa
pN2O = 143.6 kPa
The partial pressure of N2O is 143.6 kPa
Answer: 144 kPa
Explanation:
To determine the partial pressure of N2O, first determine the mole fraction of N2O in the mixture, then multiply the mole fraction of N2O by the total pressure.
XN2O = nN2O/ ntotal = 8.41 mol / 2.83 mol + 8.41 mol = 0.7482
PN2O=XN2O×Ptotal = 0.7482 × 192 kPa = 143.7 kPa
Rounding the answer to three significant figures, the partial pressure of N2O is 144kPa.
What representative units define molecular compounds and ionic compounds?
Answer:
The molecular formula of the compounds indicates the amount of atoms that the substance contains. For example, water whose formula is H2O contains 2 atoms of hydrogen and 1 of oxygen. The representative unit of a molecular compound is a molecule while ions are represented by a formula unit.
Mole can be a unit 6.02 × 10²³. The units may be electrons, atoms, ions, or molecules, depending on the nature of the substance
Explanation:
The molecular formula of the compounds indicates the amount of atoms that the substance contains. For example, water whose formula is [tex]H2O[/tex] contains 2 atoms of hydrogen and 1 of oxygen. The representative unit of a molecular compound is a molecule while ions are represented by a formula unit.
Mole can be a unit 6.02 × 10²³. The units may be electrons, atoms, ions, or molecules, depending on the nature of the substance.
Therefore, water whose formula is [tex]H2O[/tex] contains 2 atoms of hydrogen and 1 of oxygen. The representative unit of a molecular compound is a molecule while ions are represented by a formula unit.
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A chemistry student needs 65.0g of diethylamine for an experiment. By consulting the CRC Handbook of Chemistry and Physics, the student discovers that the density of diethylamine is ·0.706gcm−3. Calculate the volume of diethylamine the student should pour out.
Final answer:
To find the volume of diethylamine needed for an experiment, dividing the required mass (65.0 g) by the density of diethylamine (0.706 g/cm3) calculates a volume of 92.1 mL that the student should measure out.
Explanation:
To calculate the volume of diethylamine that a student needs for an experiment, use the formula that relates mass, density, and volume: volume = mass / density. Here, the mass required is 65.0 g, and the density of diethylamine is given as 0.706 g/cm3.
Substitute the given values into the formula:
Volume = 65.0 g / 0.706 g/cm3 = 92.1 cm3 or 92.1 mL, since 1 cm3 = 1 mL.
Therefore, the student should pour out 92.1 mL of diethylamine for their experiment.
Which of these incorrectly pairs a hormone with its function? A. thyroxin—regulates metabolism B. insulin—enables the body to use glucose (blood sugar) for energy C. adrenaline (epinephrine)—prepares the body to "fight or flee" D. progesterone—controls muscle mass
Answer:
The correct answer is D progesterone control muscle mass.
Explanation:
Progesterone is a steroid hormone synthesized from cholesterol and secreted from corpus lutenum and placenta.progesterone regulate the luteal phase of the menstrual cycle, progesterone helps in the development of secondary sexual characteristics such as breast development,pubic hair development etc.
On the other hand muscle mass is controlled by the growth hormone released from the anterior lobe of the pituitary gland.
Calcium chloride, CaCl2, is commonly used as an electrolyte in sports drinks and other beverages, including bottled water. A solution is made by adding 6.50 g of CaCl2 to 60.0 mL of water at 25∘C. The density of the solvent at that temperature is 0.997 g/mL. Calculate the mole percent of CaCl2 in the solution.
Final answer:
The mole percent of CaCl2 in the solution would be 100% if we consider only the solute, but this does not account for the water's contribution. If water's contribution to total moles were considered, the mole percent for CaCl2 would be less than 100%.
Explanation:
To calculate the mole percent of CaCl2 in the solution, we must first determine the number of moles of CaCl2.
The molar mass of CaCl2 is approximately 110.98 g/mol (40.08 g/mol for calcium and 35.45 g/mol for each chlorine, with two chlorines). With 6.50 g of CaCl2, the number of moles of CaCl2 is:
6.50 g ÷ 110.98 g/mol = 0.05855 mol
To find the total mass of the solution, the mass of CaCl2 is added to the mass of water. With the water density given as 0.997 g/mL, the mass of 60.0 mL of water is:
60.0 mL × 0.997 g/mL = 59.82 g
The total mass of the solution is thus:
6.50 g (CaCl2) + 59.82 g (H2O) = 66.32 g
To find the mole fraction of CaCl2, we divide the moles of CaCl2 by the total moles (assuming the water in the solution contributes negligibly to the total moles):
Mole fraction of CaCl2 = 0.05855 mol ÷ 0.05855 mol = 1 (since there are no other solutes)
To express this as a mole percent, we multiply the mole fraction by 100%:
Mole percent of CaCl2 = 1 × 100% = 100%
However, this calculation does not account for the water's contribution to the mole fraction. To be precise, the mole fraction and mole percent should include the moles of water as well, but since the question seems to focus solely on CaCl2, the calculation reflects this perspective. If we were to include the moles of water, the mole percent would be significantly less than 100%.
Hafnium, Hf, is also found in group 4B. Write the electron configuration for Hf. Express your answer in order of increasing orbital energy as a string without blank space between orbitals. For example, the electron configuration of Li could be entered as 1s^22s^1 or [He]2s^1.
The electron configuration for Hafnium (Hf) is [Xe]6s²4f¹⁴5d².
Explanation:The electron configuration for Hafnium (Hf) can be determined by looking at its position in the periodic table. Hafnium is in group 4B, which means it has 4 valence electrons. To write the electron configuration, we start with the noble gas that comes before Hafnium, which is Xenon (Xe).
The electron configuration for Hafnium, therefore, is [Xe]6s24f145d2.
Hafnium (Hf) has an electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d², or [Xe] 4f¹⁴ 5d² 6s².
It's part of the transition metals in group 4B.
The element hafnium (Hf) is part of the group 4B elements in the periodic table, which includes transition metals like titanium (Ti) and zirconium (Zr). Hafnium has an atomic number of 72. To determine the electron configuration of hafnium in order of increasing orbital energy, we start by filling the orbitals based on the Aufbau principle:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d².
Alternatively, in shorthand notation, this can be written as [Xe] 4f¹⁴ 5d² 6s². This configuration follows the orderly filling of orbitals, ensuring that lower energy orbitals are filled before higher energy orbitals.
The Goodyear blimp we usually see hovering above our heads at a football game contains 5600 m3 of helium gas. If there are 1070 kg of gas at an absolute pressure of 1.10 105 Pa in the blimp, what is the temperature of the gas? The atomic mass of helium 4.00260 g/mol.
The questioned tackled determining the temperature of gas in a Goodyear blimp using the provided specifications and the ideal gas law: PV=nRT.
Explanation:
The question is about determining the temperature of the helium gas in a Goodyear blimp given certain parameters. Using the ideal gas law: PV=nRT we can calculate the temperature (T). In this scenario, the volume (V) is 5600 m3, the pressure (P) is 1.10x105 Pa and the number of moles (n) can be calculated by dividing the total mass of helium gas by its molar mass. By rearranging the gas law formula, the temperature could be calculated as T=(PV)/(nR), where R is the gas constant.
Following these steps, we can substitute the known values into the equation to solve for the temperature inside the Goodyear blimp. This problem involves concepts of physics, specifically gas laws, and would be covered typically in a college-level physics course.
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Write a balanced chemical equation, including physical state symbols, for the decomposition of solid calcium carbonate (CaCO₃) into solid calcium oxide and gaseous carbon dioxide. Suppose 23.0 L of carbon dioxide gas are produced by this reaction, at a temperature of 380.0 °C and pressure of exactly 1 atm. Calculate the mass of calcium carbonate that must have reacted. Be sure your answer has the correct number of significant digits.
Answer:
CaCO3 (s) → CaO (s) + CO2 (g)
The mass of carbonate that must have reacted was 43.03 grams
Explanation:
CaCO3 → CaO + CO2
Relation between reactant and product is 1:1
Let's apply the Ideal Gas Law to find out the moles of CO2 which were produced.
P . V = n . R . T
1 atm . 23 L = n . 0.082 L.atm/mol.K . 653K
(1atm . 23L) / (0.082 mol.K/L.atm . 653K) = n
0.43 moles = n
0.43 moles of CO2, were produced from 0.43 moles of CaCO3.
Molar weight of CaCO3 = 100.08 g/m
Mass = Molar weight . moles
Mass = 100.08 g/m 0.43 m = 43.03 g
The decomposition of calcium carbonate (CaCO₃) can be represented by the equation: CaCO₃(s) → CaO(s) + CO₂(g). Using the ideal gas law, we calculate that approximately 43.1 grams of CaCO₃ reacted to produce 23.0 liters of CO₂ at 380.0 °C and 1 atm pressure.
Decomposition of Calcium Carbonate:
The balanced chemical equation for the decomposition of solid calcium carbonate (CaCO₃) into solid calcium oxide (CaO) and gaseous carbon dioxide (CO₂) is:
CaCO₃(s) → CaO(s) + CO₂(g)
To calculate the mass of calcium carbonate that reacted to produce 23.0 L of CO₂ gas at 380.0 °C and 1 atm, we use the ideal gas law. The ideal gas law is expressed as:
PV = nRT
Where:
P = pressure (1 atm)V = volume (23.0 L)n = moles of gasR = ideal gas constant (0.0821 L·atm/mol·K)T = temperature in Kelvin (380.0 °C + 273.15 = 653.15 K)Rearranging the ideal gas law to solve for n (moles of CO₂) gives:
n = PV / RT
Substituting the known values:
n = (1 atm * 23.0 L) / (0.0821 L·atm/mol·K * 653.15 K) ≈ 0.431 moles of CO₂
From the balanced equation, 1 mole of CaCO₃ produces 1 mole of CO₂. Hence, the moles of CaCO₃ that reacted is also 0.431 mol.
The molar mass of CaCO₃ is approximately 100.09 g/mol.
The mass of CaCO₃ that reacted is:
mass = moles * molar mass
mass = 0.431 mol * 100.09 g/mol ≈ 43.1 g
Thus, about 43.1 grams of calcium carbonate must have reacted.
The mass of solute per 100 mL of solution is abbreviated as (m/v). Mass is not technically the same thing as weight, but the abbreviation (w/v) is also common. How many grams of sucrose are needed to make 765 mL of a 31.0 % (w/v) sucrose solution?
Answer:
There are needed 237.15 g of sucrose.
Explanation:
The 31.0 % (w/v) of the sucrose solution means that in 100 ml of solution, you have 31 g of solute, in this case sucrose.
So you want to make a solution with 765 mL.
Let's think the rule of three:
100 mL solution__contain __31 g sucrose
765 mL solution _________ (765 . 31 ) /100 = 237.15 g
A 12-liter tank contains helium gas pressurized to 160 \rm atm.How many 3-liter balloons could the 12-L helium tank fill? Keep in mind that an "exhausted" helium tank is not empty. In other words, once the gas inside the tank reaches atmospheric pressure, it will no longer be able to fill balloons.
Answer:
636 balloons
Explanation:
If we assume that helium gas follows an ideal gas behaviour, we can use the ideal gas law to solve this problem as follows:
We consider two different states, the initial given by the conditions of the problem statement and the final, when the tank reaches atmospheric pressure and it's no longer able to fill balloons:[tex]P_{1}=160 atm\\V_{1}=12 L\\P_{2}=1 atm\\V_{2}= ?[/tex]To find out what would be this volume 2, we use the Boyle's Law: [tex]P_{1}V_{1}=P_{2}V_{2}\\V_{2}=\frac{P_{1}V_{1}}{P_{2}} \\V_{2}=\frac{160 atm \times 12L}{1 atm}\\V_{2}=1920 L[/tex]Now we find the available volume to fill the balloons by substracting both, volume 2 and volume 1: [tex]V_{b}=V_{2}-V_{1}=1920L-12L=1908 L[/tex]Finally, we determine the quantity of ballons by dividing that available volume between the volume of each ballon:[tex]B=\frac{1908L}{3L} =636 balloons[/tex]By applying Boyle's Law that states the pressure of a gas is inversely proportional to its volume, we find that the 12-L tank pressurized to 160 atm can fill a total of 640 3-L balloons to atmospheric pressure.
Explanation:This is a typical problem related to the ideal gas law and mainly involves the understanding of pressure-volume relationship in gases. Since the tank and the balloons are at different pressures, the volume the helium will occupy in the balloons at atmospheric pressure will be larger than the volume it occupies in the tank.
Based on this, if the helium tank is pressurized to 160 atm and the balloons are to be filled until the pressure in the tank is equivalent to atmospheric pressure (1 atm), the helium in the tank will expand 160 times its initial volume. Hence, the 12-L tank will fill 12 * 160 = 1920 L of balloon space. Given each balloon has a volume of 3 L, the number of balloons that can be filled is thus 1920 / 3 = 640 balloons.
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A moving company is called into a building and asked to relocate 520 bricks to a location 15 meters above the ground. If each brick is 4 kilograms, what amount of work will be needed to accomplish the task?A. 305,760 JB. 229,320 JC. 203,840 JD. 588,000 J
Answer: A. 305,760 J
Explanation:
Work is defined as a force causing the movement or displacement of an object.
work=[tex]mass\times acceleration\times height[/tex]
Given: m= mass = 4 kg
g= acceleration due to gravity = [tex]9.80m/s^2[/tex]
h = height = 15m
Putting in the values we get,
work=[tex]4kg\times 9.80m/s^2\times 15m=588J[/tex]
[tex]1kgm^2s^{-2}=1Joule(J)[/tex]
Now 520 bricks are to be relocated, thus work done = [tex]520\times 588J=305760J[/tex]
Thus amount of work will be needed to accomplish the task is 305760 J.
An example of a synthesis is the Statue of Liberty turning green. Oxygen in the air combines with the copper statue to form copper oxide, which is green. Which of these is the correct chemical reaction for this?
A) Cu + O → CuO
B) Cu + O2 → CuO
C) CuO → Cu + O2
D) 2 Cu + O2 → 2CuO
Answer:
D. 2Cu + O2 = 2CuO
Explanation:
Then CuO, which is black, reacts with CO2 to form CuCO3 which is green.
Answer : The correct chemical reaction is, (D)
Explanation :
Synthesis reaction : It is defined as a chemical reaction where multiple substances or reactants combine to form a single product.
It is represented as,
[tex]X+Y\rightarrow XY[/tex]
When copper react with an oxygen then it react to give copper oxide as a product.
The balanced chemical reaction will be:
[tex]2Cu+O_2\rightarrow 2CuO[/tex]
Hence, the correct chemical reaction is, (D)
The heat of vaporization of water at 100°c is 40.66 kj/mol. Calculate the quantity of heat that is absorbed/released when 9.00 g of steam condenses to liquid water at 100°c.
When 9.00g of steam condenses to liquid water at 100°C, 20.3 kJ of heat is released. This is calculated by converting the mass of water to moles, then multiplying by the heat of vaporization.
Explanation:The heat absorbed or released during the condensation of steam to liquid water is calculated by using the heat of vaporization (40.66 kJ/mol) and the moles of water. The mass of water given is 9.00g, which is converted to moles by dividing by the molar mass of water (18.02g/mol), resulting in 0.499 mol of water. The heat absorbed/released (Q) is calculated by multiplying the number of moles and the heat of vaporization. So, Q = 0.499 mol * 40.66 kJ/mol = 20.3 kJ (3 sig figs). So when 9.00g of steam condenses to liquid water at 100°C, 20.3 kJ of heat is released.
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The natural tendence of an object to resist change in its state of motion is:
friction
force
inertia
gravity
Answer:
inertia
Explanation:
The principal of inertia explains why objects do not voluntarily change their speed or direction without the influence of an external force. Inertia is not unaffected by other forces in planetary systems such as Earth and is, as such, not really observable on planetary surfaces. This is due to the resistance forces of gravity and friction from both the air and the ground. The drag slows objects down and makes it appear as if a constant force were necessary to keep them in motion.
Answer:
c
Explanation:
A buffer with a pH of contains M of sodium benzoate and M of benzoic acid. What is the concentration of in the solution after the addition of mol to a final volume of L? Assume that any contribution of to the volume is negligible.please Answer for H3O+. will rate
Answer:
benzoic acid(C7H6O2)--->
C7H5NaO2(sodium benzoate)+H30+
The answer is given per the balanced eqn
Which one of the following statements is not true?
a. Basalt magmas, in general, have higher temperatures than rhyolite magmas.
b. When magma reaches the surface, its dissolved gas content increases.
c. Melting temperatures of silicate rocks are lowered by small amounts of water.
d. Melting temperatures of silicate rocks increase with increased pressure.
Answer:
When magma reaches the surface, its dissolved gas content increases is true
Explanation:
The volcanic eruptions happen because of magma that is expelled on the earth’s surface. At the earth’s depth, all magma have gas dissolved in liquid. When the pressure has decreased the magma rises towards the earth’s surface creating a separate vapour phase.
As pressure reduces the volume of gas will expands and giving magma its 'explosive character'. Thus, as magma reaches the surface the dissolved gas content decreases and magma comes out of earth’s surface.
The untrue statement is b, as the dissolved gas content in magma decreases as it reaches the surface due to reduced pressure. Basalt magma has higher temperatures than rhyolite magma. Water reduces the melting temperature of silicate rocks, and increased pressure raises it.
Explanation:The subject here pertains to volcanic activity and magma characteristics. The statement that is not true is: b. When magma reaches the surface, its dissolved gas content increases. In fact, as magma rises to the surface, the pressure decreases which allows the dissolved gases to escape, thus its dissolved gas content actually decreases. Statements a, c and d are true - Basalt magmas do generally have higher temperatures than rhyolite magmas. Additionally, the presence of water does indeed lower the melting temperature of silicate rocks, and increased pressure results in a higher melting temperature for these rocks.
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In the laboratory, a student uses a coffee cup calorimeter to determine the specific heat of a metal. She heats 18.1 grams of lead to 99.50°C and then drops it into a cup containing 81.7 grams of water at 23.00°C. She measures the final temperature to be 23.67°C. Assuming that all of the heat is transferred to the water, she calculates the specific heat of lead to be _____ J/g°C.
Answer:
[tex]specificheat=0.177J/g^{0}C[/tex]
Explanation:
The heat evolved by lead will be absorbed by water.
The heat evolved by lead will be:
[tex]Q1=massXspecificheatXchangeintemperature[/tex]
[tex]Q1=18.1X(Specificheat)X(99.50-23.67)[/tex]
Heat absorbed by water will be:
[tex]Q2=massXspecificheatX(changeintemperature)[/tex]
[tex]Q2=81.7X4.184(23.67-23)=229.03J[/tex]
We know that
Q1=Q2
[tex]18.1X(Specificheat)X(99.50-23.67)=229.03[/tex]
[tex]1372.523Xspecificheat=229.03[/tex]
[tex]specificheat=0.177J/g^{0}C[/tex]
Cesium chloride has a lattice energy -657.0 kJ/mol and a heat of hydration of -639.0 kJ/mol. Determine how much heat is evolved or absorbed when 30.0 g of cesium chloride completely dissolves in water.
Answer:
Q = 3.21 kJ
Explanation:
First, with the heat of hydration and the lattice energy, we can actually calculate the difference between those two to get the heat evolved per mole. In this case it would be:
657 - 639 = 18 kJ/mol
Now, the expression to get the heat is:
Q = m*ΔE
We already have the energy, now we need to get the moles of the cesium chloride.
The molar mass of cesium chloride is 168.36 g/mol, so the moles:
mole = 30/168.36 = 0.1781 moles
Finally the heat:
Q = 0.1781 * 18
Q = 3.21 kJ
Bromine has two isotopes 79Br and 81Br, whose masses (78.9183 and 80.9163 amu) and abundances (50.69% and 49.31%, respectively) were determined in earlier experiments. Calculate the average atomic mass of bromine based on these experiments.
Answer:
Average atomic mass = 79.9034 amu
Explanation:
The formula for the calculation of the average atomic mass is:
[tex]Average\ atomic\ mass=(\frac {\%\ of\ the\ first\ isotope}{100}\times {Mass\ of\ the\ first\ isotope})+(\frac {\%\ of\ the\ second\ isotope}{100}\times {Mass\ of\ the\ second\ isotope})[/tex]
Given that:
For first isotope:
% = 50.69 %
Mass = 78.9183 amu
For second isotope:
% = 49.31 %
Mass = 80.9163 amu
Thus,
[tex]Average\ atomic\ mass=\frac{50.69}{100}\times {78.9183}+\frac{49.31}{100}\times {80.9163}\ amu[/tex]
[tex]Average\ atomic\ mass=40.0036+39.8998\ amu[/tex]
Average atomic mass = 79.9034 amu
Final answer:
The average atomic mass of bromine is calculated by taking the sum of the products of each isotope's mass and its abundance in decimal form. The result is an average atomic mass of 79.898 amu for bromine.
Explanation:
To calculate the average atomic mass of bromine based on the given experimental results, we need to consider the masses and relative abundances of its isotopes. By multiplying the mass of each isotope by its abundance (converted to a decimal form) and adding these weighted masses together, we can determine the average atomic mass.
Calculation:
Adding the weighted masses of both isotopes gives us: 39.994 amu + 39.904 amu = 79.898 amu. Thus, the average atomic mass of bromine based on these experiments is 79.898 amu.
Checking for Accuracy:
It is important to make sure that this number makes sense and correlates with the given abundances, ensuring that no mathematical errors have been made.
B5H9(l) is a colorless liquid that will explode when exposed to oxygen. How much heat is released when 0.211 mol of B5H9 reacts with excess oxygen where the products are B2O3(s) and H2O(l). The standard enthalpy of formation of B5H9(l) is 73.2 kJ/mol, the standard enthalpy of formation of B2O3(s) is -1272 kJ/mol and that of H2O(l) is -285.4 kJ/mol. Express your answer in kJ.
Answer:
Heat realesed is - 2192.7 kJ
Explanation:
First lets have the chemical equation balanced, and then solve the question based on the fact that the enthalpy change for a reaction is the sum of the enthalpies of formation of products minus reactants.
B₅H₉ (l) + O₂ (g) ⇒ B₂O₃ (s) + H₂O(l)
B atoms we have 5 reactants and 2 products, so the common mltiple is 10 and we have
2 B₅H₉ (l) + O₂ (g) ⇒ 5 B₂O₃ (s) + H₂O(l)
Now balance H by multiplying by 9 the H₂O
2 B₅H₉ (l) + O₂ (g) ⇒ 5 B₂O₃ (s) + 9 H₂O(l)
Finally, balance the O since we have 24 in products by multiplying by 12 the
O₂ ,
2 B₅H₉ (l) + 12 O₂ (g) ⇒ 5 B₂O₃ (s) + 9 H₂O
ΔHrxn = 5 x ΔHºf B₂O₃ + 9 x ΔHºf H₂O - ( 2 x ΔHºf B₅H₉ + 12 x ΔHºf O₂ )
We have all the ΔHºf s except oxygen but remember the enthalpy of formation of a pure element in its standard estate is cero.
ΔHrxn = 5 mol x ( -1272 kJ/mol )+ 9 mol x ( -285.4 kJ/mol ) - ( 2mol x 732 kJ/mol )
= -8928.6 kJ - 1464 kJ = -10,392 kJ
Now this enthalpy change was based in 2 mol reacted according to the balanced equation, so for 0.211 mol of B₅H₉ we will have:
-10,392 kJ/ 2 mol B₅H₉ x 0.211 mol B₅H₉ = - 2192.7 kJ
Answer:
ΔH=-957.41 kJ
Explanation:
The chemical equation is:
B₅H₉ (l) + O₂ (g) ⇒ B₂O₃ (s) + H₂O(l)
The law of conservation of matter states that since no atom can be created or destroyed in a chemical reaction, the number of atoms that are present in the reagents has to be equal to the number of atoms present in the products.
Then, you must balance the chemical equation. For that, you must first look at the subscripts next to each atom to find the number of atoms in the equation. If the same atom appears in more than one molecule, you must add its amounts
The coefficients located in front of each molecule indicate the amount of each molecule for the reaction. This coefficient can be modified to balance the equation, just as you should never alter the subscripts.
By multiplying the coefficient mentioned by the subscript, you get the amount of each element present in the reaction.
So in first place you balance B
2 B₅H₉ (l) + O₂ (g) ⇒ 5 B₂O₃ (s) + H₂O(l)
Then you balance H
2 B₅H₉ (l) + O₂ (g) ⇒ 5 B₂O₃ (s) + 9 H₂O(l)
Finally you balance O
2 B₅H₉ (l) + 12 O₂ (g) ⇒ 5 B₂O₃ (s) + 9 H₂O(l)
Then
Left side: 2*5=10 boron (B), 2*9=18 hydrogen. and 12*2=24 oxygen
Right side: 5*2=10 boron (B), 9*2=18 hydrogen. and 5*3 + 9*1=24 oxygen
Since you have the same amount of elements on each side of the equation, the equation is balanced.
You want to calculate the ∆H (heat of reaction) of the combustion reaction, that is, the heat that accompanies the entire reaction. For that you must make the total sum of all the heats of the products and of the reagents affected by their stoichiometric coefficient (quantity of molecules of each compound that participates in the reaction) and finally subtract them:
Enthalpy of combustion = ΔH = ∑Hproducts - ∑Hreactants
Knowing that:
Heat of formation of B₅H₉ = 73.2 kJ/mol Heat of formation of water = -285.4 kJ/mol Heat of formation of B₂O₃ = -1,272 kJ/molFor the formation of one mole of a pure element the heat of formation is 0, in this case we have as a pure compound the oxygen O₂.
Then:
ΔH= 9 mol*(-285.4 kJ/mol) + 5 mol* (-1,272 kJ/mol) - [2 mol* 73.2 kJ/mol + 12 mol* 0 kJ/mol]
ΔH= -9,075 kJ
If you observe the previous balanced reaction, you can see that 2 moles of B₅H₉ (l) are necessary. And the calculation of the heat of reaction previously carried out is based on this reaction. This ultimately means that the energy that would result in the reaction of 2 moles of B₅H₉ (l) is -9,075 kJ.
To determine the heat that is released when 0.211 mol of B₅H₉ (l) react with excess oxygen, a rule of three is applied as follows: if 2 moles of B₅H₉ (l) produces a heat ΔH of -9,075 kJ, when reacting 0.211 mol of B₅H l (l) how much heat ΔH is released?
ΔH=[tex]\frac{0.211 moles*(-9075)kJ}{2 moles}[/tex]
ΔH=-957.41 kJ
[tex]H_2(g) + I_2(g) \longrightarrow 2HI(g)[/tex]
The forward reaction above is exothermic. At equilibrium, what happens if the reaction mixture is cooled at constant volume?
Select all that apply.
1. The reaction absorbs energy.
2. The reaction releases energy.
3. [H₂] and [I₂] increase.
4. [H₂] and [I₂] decrease.
5. [H₂] and [I₂] remain constant.
6. [HI] increases.
7. [HI] decreases.
8. [HI] remains constant.
If C is added to the equilibrium system above, in which direction will the equilibrium shift?
Answer:
The appropriate options are:
2. The reaction releases energy.
4. [tex][H_{2}][/tex] and [tex][I_{2}][/tex] increase.
6. [tex][HI][/tex] increases.
The addition of a non-reacting component C will have no effect on the equilibrium system at constant volume.
Explanation:
[tex]H_{2}+I_{2}\longrightarrow2HI(exothermic)[/tex]
The question can be answered by using Le Chatelier's principle.
According to Le Chatelier's Principle, for a exothermic reaction, decreasing the temperature at equilibrium will cause the forward reaction to occur.
If the forward reaction occurs, subsequently the concentrations of the reactants will decrease and that of the product will increase.
This is the reason for the options 4 and 6 being correct.
Exothermic reactions are the ones that release energy and endothermic reactions are the ones that absorb energy.
Since the forward reaction is exothermic, cooling the reaction mixture at constant volume, will lead to a release of energy.
This is the reason for the option 2 to be correct.
If a component C is added at constant volume, there will be no effect on the equilibrium system, assuming that the component C is non-reacting.
The concentration of that component C will increase, at constant volume.
The pH scale for acidity is defined by pH=−log10[H⁺] where [H⁺]is the concentration of hydrogen ions measured in moles per liter (M). A solution has a pH of 12.25. Calculate the concentration of hydrogen ions in moles per liter (M). The concentration of hydrogen ions is ___________ moles per liter.
Answer:
5.62 * 10^-13 moles per liter
Explanation:
The pH of a solution is the negative logarithm to base 10 of the concentration of hydrogen ions. What we simply do here is to input the information in the question into the equation:
pH=−log10[H⁺]
Here we know the pH but we do not know the concentration of the hydrogen ions.
12.25 = -log [H+]
log[H+] = -12.25
[H+] = 10^-12.25
[H+] = 5.62 * 10^-13 moles per liter
The concentration of hydrogen ions in the solution with a pH of 12.25 is calculated using the formula [H⁺] = 10^(-pH) which gives a result of 10^(-12.25) moles per liter.
Explanation:The pH scale for acidity is defined by pH=-log10[H+] where [H+] is the concentration of hydrogen ions. A solution has a pH of 12.25. Given that the pH = -log10[H⁺], to get the hydrogen ion concentration when the pH value is known, you rearrange the pH formula to the following: [H⁺] = 10^-pH. Substituting 12.25 for pH, the concentration of hydrogen ions in the solution is 10^(-12.25) moles per liter. This calculation is based on the principles of logarithms and the properties of the pH scale.
Learn more about pH scale here:https://brainly.com/question/1433865
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________ is an indication of how near the air is to saturation rather than the actual quantity of water vapor in the air.
Answer: Relative humidity
Explanation:
Relative humidity (RH) is the ratio of the partial pressure of water vapor to the equilibrium vapor pressure of water at a given temperature. Relative humidity depends on temperature and the pressure of the system of interest. The same amount of water vapor has higher relative humidity in cool air than in warm air. A related parameter to that regard is that of dew point.
Consider the reaction: H2(g) + I2(g)->2HI(g)
A reaction mixture in a 3.67-L flask at a certain temperature initially contains 0.763 g H2 and 96.9 g I2. At equilibrium, the flask contains 90.4 g HI. Calculate the equilibrium constant (Kc) for the reaction at this temperature.
To calculate the equilibrium constant (Kc) for the reaction H2(g) + I2(g) \ightarrow 2HI(g), the moles of each reactant and product at equilibrium were calculated and then converted to concentrations. Using the concentrations, the Kc was determined to be approximately 610.97.
The reaction in question is H2(g) + I2(g) \ightarrow 2HI(g). To calculate the equilibrium constant (Kc), we need to determine the moles of HI, H2, and I2 at equilibrium. The molecular weights of H2, I2, and HI are approximately 2 g/mol, 254 g/mol, and 128 g/mol, respectively.
Initial moles of H2 = 0.763 g / 2 g/mol = 0.3815 mol
Initial moles of I2 = 96.9 g / 254 g/mol = 0.3815 mol
At equilibrium, there are 90.4 g of HI:
Equilibrium moles of HI = 90.4 g / 128 g/mol = 0.70625 mol
Since the reaction produces 2 moles of HI for every 1 mole of H2 and I2 that react, 0.70625 mol of HI would require half that amount of H2 and I2 to react:
Moles of H2 and I2 reacted = 0.70625 mol HI / 2 = 0.353125 mol
Moles of H2 and I2 at equilibrium = initial moles - moles reacted
Equilibrium moles of H2 = 0.3815 mol - 0.353125 mol = 0.028375 mol
Equilibrium moles of I2 = 0.3815 mol - 0.353125 mol = 0.028375 mol
We then convert these moles to concentrations by dividing by the volume of the flask:
[H2] = 0.028375 mol / 3.67 L \hickapprox 0.007732 M
[I2] = 0.028375 mol / 3.67 L \hickapprox 0.007732 M
[HI] = 0.70625 mol / 3.67 L \ hickapprox 0.192398 M
Now, we can calculate the equilibrium constant Kc
Kc = [HI]² / ([H2][I2]) = (0.192398 M)² / (0.007732 M × 0.007732 M) \hickapprox 610.97