There are ________ hydrogen atoms in 25 molecules of c4h4s2.
Answer: 100.
Explanation:
1) The subscripts to the right of each element (symbol) in the chemical formula tells the number of atoms of that element present in one unit formula.
2) The unit formula of C₄H₄S₂ is equal to 1 molecule.
3) Therefore, there are 4 carbon atoms, 4 hydrogen atoms and 2 sulfur atoms in each molecule of C₄H₄S₂.
4) Then, you just have to multiply the corresponding subscript of the element times the number of molecules (25 in this case) to find the number of atoms of that kind.
5) These are the calculations for each element in the molecule C₄H₄S₂.
i) C: 4 × 25 = 100
ii) H: 4 × 25 = 100
iii) S: 2 × 25 = 50.
6) The question is about H only, so the answer is that there are 100 hydrogen atoms in 25 molecules of C₄H₄S₂.
#1: Jim, Jane, Ann, and Bill measure an object’s length, density, mass, and volume, respectively. Which student’s measurement might be in centimeters?
A. Bill’s
B. Jane’s
C. Jim’s
D. Ann’s
**MY answer: C. Jim's
#2: How many centimeters are in 0.05 kilometers?
A. 50
B. 500
C. 5,000
D. 50,000
***My answer: C. 5,000
The ionization of pure water forms _____.
Answer: The ionization of pure water forms hydroxide and hydronium ions.
Explanation:
Ionization is a reaction in the pure water in which water breaks down into its constituting ions that hydronium ion and hydroxide ions.
[tex]H_2O+H_2O\rightleftharpoons H_3O^++OH^-[/tex]
One molecule of water looses its proton to form hydroxide ion and l=the lost protons get associated with another water molecule to form hydronium ion.
Which of the following compounds has the highest boiling point?
2-pentanone
pentene
chloropentane
pentane
Answer: chloropentane
Explanation:
When a hydrocarbon has a halogen atom, its properties will change because this group has a higher molecular weight and a higher polar moment that will be hard to defeat in order to reach the boiling point.
The Boiling point of the pentene is 30°C // pentane is 36,1°C // 2-pentanone is 101°C and chloropentane 108°C.
Simple hydrocarbons have lower boiling points compare with those with a functional group like the Oxygen in the 2-pentanone and the Chlorine in the chloropentane. On the other heand, Oxygen is not as electronegative and heavy like Chlorine, thus the chloropentane is the one with higher boiling point.
How much energy is evolved during the formation of 197 g of fe, according to the reaction below? fe2o3(s) + al(s) → al2o3(s) + fe(s) δh°rxn = -852 kj?
Answer : The energy evolved in the reaction is 1499.52 kJ
Explanation : Given,
Mass of Fe = 197 g
Molar mass of Fe = 56 g/mole
Enthalpy of reaction = -852 kJ
First we have to calculate the moles of Fe.
[tex]\text{ Moles of Fe}=\frac{\text{ Mass of Fe}}{\text{ Molar mass of Fe}}=\frac{197g}{56g/mole}=3.52moles[/tex]
Now we have to calculate the energy evolved in the reaction.
From the balanced chemical reaction we conclude that,
As, 2 mole of Fe evolved energy = 852 kJ
So, 3.52 mole of Fe evolved energy = [tex]\frac{3.52}{2}\times 852kJ[/tex]
= 1499.52 kJ
Therefore, the energy evolved in the reaction is 1499.52 kJ
If a 3.30 m sample of a is heated to 500 k, what is the concentration of b at equilibrium?
To find the concentrations at equilibrium, one would use the equilibrium constant (K). Given known concentrations and the stoichiometry of the reaction, one can solve for the unknown concentration. Be sure to convert all quantities to appropriate units (molarity), and remember that these calculations assume that the system is at equilibrium.
Explanation:The question pertains to chemical equilibrium, particularly the equilibrium for the reaction N₂(g) + 3H₂(g) = 2NH3(g) at 500 k. It seems like there could be some missing details in the question, so I'll provide a general approach to solving problems like this.
To find the concentrations at equilibrium, we can use the concept of equilibrium constants. In this case, the equilibrium constant (K) for the reaction N₂(g) + 3H₂(g) = 2NH3(g) would be expressed as K = [NH3]² / ([N2][H2]³). Plugging in the known concentrations, one can solve for the unknown, which might be the concentration of 'b' referred to in the original question.
Note that the concentrations should be in molarity (M) units, which represent moles of solute per liter of solution. Therefore, the 3.30 m sample needs to be converted into volume (in litres) to derive the molarity given the number of moles of the substance.
Remember that calculations with equilibrium constants assume that the system has reached equilibrium, and that temperature remains constant. If the actual situation doesn't meet these conditions, more complex calculations might be needed.
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Consider the data presented below. time (s) 0 40 80 120 160 moles of a 0.100 0.067 0.045 0.030 0.020 part a part complete determine whether the reaction is first order or second order. determine whether the reaction is first order or second order. this is the first order reaction. this is the second order reaction. submitprevious answers correct part b what is the rate constant?
The reaction is likely first order as indicated by the provided rate constant which aligns with the characteristics of a first-order reaction.
Explanation:To determine whether the reaction is first order or second order, we need to consider the rate at which the concentration of A changes over time. For a first order reaction, the rate of reaction is directly proportional to the concentration of the reactant. This means that if you were to plot the natural logarithm (ln) of the concentration of A versus time, you would see a linear relationship.
In contrast, a second order reaction implies that the rate is proportional to the square of the concentration of the reactant. Here, plotting the inverse of the concentration of A versus time would yield a linear relationship.
Given that the rate constant for the reaction is expressed as k = 1.0 × 107 L mol−1 min−1, this is indicative of a first order reaction, as it does not include a squared concentration term. Therefore, based on the provided information, the reaction is first order.
Which of the following can explain the daily change in sea level observed along a coast?
A. The gravitational pull of the moon on the water near the coast
B. The speed of the ocean's conveyor belt near the coast
C. Earthquakes and volcanoes near the coast
D. The concentration of salt in the water near the coast
Assuming complete dissociation, what is the molality of k+, br− in an aqueous solution of kbr whose freezing point is -2.53 ∘c? the molal freezing-point-depression constant of water is 1.86 (∘c⋅kg)/mol.
Valence electrons are responsiblefor the makeup of chemical properties of elements true or false
Answer:
WRONG-the answer is TRUE
Explanation:
When substances go through chemical changes, which of the following will always happen? A. Exactly one new substance will form and one will be destroyed. B. One or more substances with different chemical properties will form. C. One or more substances will be completely destroyed. D. A gas will form or a white solid will precipitate.
If a balloon at 10 oC goes from 30L to 2L, what is the final temperature?
Question 4 options:
18.87
4.72
0.21
16,980.00
8490.00
Assume that 1.0 mol of C4H10 is completely burned in excess oxygen to form carbon dioxide and water. How many moles of CO2 would be produced?
Final answer:
The complete combustion of 1.0 mole of C4H10 (butane) in excess oxygen will produce 4 moles of carbon dioxide (CO2).
Explanation:
To determine how many moles of carbon dioxide (CO₂) are produced when 1.0 mole of C₄H₁₀ (butane) is completely burned in excess oxygen, we need to first write and balance the chemical equation for the combustion of butane. The balanced chemical equation for the combustion of butane is:
C₄H₁₀ + 6.5O₂ → 4CO₂ + 5H₂O
This equation shows that 1 mole of butane reacts with 6.5 moles of oxygen to produce 4 moles of CO₂ and 5 moles of water (H₂O). Therefore, the complete combustion of 1.0 mole of C₄H₁₀ will produce 4 moles of carbon dioxide.
How does hydrogen bonding affect the physical properties of substances?
Final answer:
Hydrogen bonding affects the physical properties of substances such as water and carboxylic acids by increasing their boiling point, melting point, solubility, heat capacity, surface tension, and viscosity due to the additional attractive intermolecular forces these bonds provide.
Explanation:
Hydrogen bonding significantly influences the physical properties of substances. These intermolecular forces occur when a hydrogen atom bonded to a strongly electronegative atom, like oxygen or nitrogen, is attracted to another electronegative atom in a nearby molecule. This attraction leads to a type of bond that, while not as strong as a covalent bond, significantly affects a substance's physical characteristics.
For instance, in water molecules, hydrogen bonds form between the positively charged hydrogen atom of one molecule and the negatively charged oxygen atom of another. This results in a network of bonds that increase the melting point and boiling point of water, compared to what would be expected based on its molecular weight alone. It's also the reason why water has a high heat capacity, surface tension, and viscosity.
In the case of carboxylic acids, hydrogen bonding allows these molecules to dimerize (form pairs), which enhances their boiling points and makes them more soluble in water than comparable hydrocarbons. When carboxylic acids dissolve in water, the hydrogen bonding facilitates the interaction between acid molecules and water, which is crucial for their dissolution and the resultant physical properties.
How many more valence electrons does oxygen need to have a full outer valence shell?
Which hypothesis led to the discovery of the proton?
Answer:
a ) when a neutral hydrogen atom loses an electron, a positively-charged particle should remain
A student is told that both energy and mass must be conserved in every chemical reaction. She measures the mass of Hydrochloric acid and a zinc strip separately. She then places the zinc strip into the acid and bubbles form as the zinc looks like it disappears. The combined mass afterward is less than the original.
Answer:
Explanation:
When we react Hydrochlorid Acid with zinc we have the following reaction:
2HCl(aq) + Zn(s) --> ZnCl2(aq) + H2(g)
The hydrogen gas formed is lost to the environment, so we can affirme that in the start we have the mass for all the H, Cl and Zn atoms in the solution, but after the reaction occurs, we have only the mass for the Cl and Zn atoms.
That's why the mass is less than the original.
The law that the student was told is only applied to closed environments.
In bowen's discontinuous reaction series, the first mineral to crystallize out of a mafic melt is __________ .
Final answer:
The correct answer is "olivine". In Bowen's discontinuous reaction series, olivine is the first mineral to crystallize from a mafic melt. It later reacts to form pyroxene as the magma cools. This series helps us understand mineral crystallization and the formation of igneous rocks.
Explanation:
In Bowen's discontinuous reaction series, the first mineral to crystallize from a mafic melt is olivine. The process of crystallization in a cooling magma begins with high-temperature minerals like olivine. As the temperature of the magma decreases, different minerals begin to crystallize while others become unstable, with olivine reacting with silica to form pyroxene at lower temperatures. This reaction is represented by the equation Mg2SiO4 + SiO2 > 2MgSiO3, turning olivine into pyroxene. Through Bowen's reaction series, we understand that the crystallization of minerals removes elements such as magnesium (Mg) and iron (Fe) from the magma, altering its composition over time. These early-formed minerals are known as phenocrysts, and their formation is sequential based on the cooling of the magma. Bowen's reaction series not only informs us about mineral crystallization sequences but also about the formation of different igneous rocks and their compositions.
One way the modern atomic model differs from Thomson's atomic model is that electrons are no longer scattered throughout and atom's positive matter like chocolate chips in a cookie dough. instead, each electron is outside of the nucleus occupying a specific ___
Which of the following is essential for a theory to become widely accepted within the scientific community? (2 points)
A theory must include a valid scientific model.
A theory must be supported by many different experiments.
A theory is an educated guess based on multiple observations.
A theory must change over time regardless of the scientific data.
Answer:
A theory must be supported by many different experiments.
Explanation:
It is important for a theory to be tested by different independent science labs. When the same data are observed only then the theory reaches a consensus in the scientific community. A theory is based on evidence and not on educated guess. A scientific theory withstands rigorous scrutiny before it becomes accepted by the scientific community. Hence option B in correct.
How does the shape of a molecule factor into its molecular polarity?
How are greenhouse gases like carbon dioxide and methane different from other atmospheric gases like nitrogen and oxygen?
Predict the bond present between carbon and hydrogen in polyethylene
What pressure will be exerted by 0.650 mol of a gas at 30.0C if it is contained in a 0.700 L vessel?
Which of the following statements best describes Kepler's law of ellipses?
Each planet orbits the sun in an elliptical shape with the sun at one of the ellipse's two focal points.
An ellipse has two focal points. The sun is at one focal point of an ellipse. The other focal point is the planet that orbits the sun.
The planets orbit the sun in a perfect circle. The sun is an elliptical shape.
Planets must orbit the sun in an elliptical shape because an ellipse has two focal points.
Answer : Each planet orbits the sun in an elliptical shape with the sun at one of the ellipse's two focal points.
Explanation:
Kepler's Law of ellipses: This law explains the path of the planet around the sun
The orbit of the planet around the sun is an ellipse shape, where sun is present on the one of the focus.
From the given options the correct option is:
Each planet orbits the sun in an elliptical shape with the sun at one of the ellipse's two focal points.
NaCl + AgNO3 —> AgCl + NaNO3
How much AgNO3 is consumed during the reaction with 78 g of NaCl?
Final answer:
To find the amount of AgNO₃ consumed, calculate the moles of NaCl present in 78 g and use the one-to-one mole ratio of the reactants to determine the moles and then the mass of AgNO₃ consumed, which is 226.86 grams.
Explanation:
To calculate how much AgNO₃ is consumed in the reaction with 78 g of NaCl, we first need to understand the stoichiometry of the reaction. The balanced chemical equation is:
NaCl (aq) + AgNO₃ (aq) → AgCl (s) + NaNO₃ (aq)
This indicates that 1 mole of NaCl reacts with 1 mole of AgNO₃ to produce 1 mole of AgCl and 1 mole of NaNO₃.
First, we must examine the reaction stoichiometry, which is a one-to-one ratio. Therefore, we need to calculate the number of moles of NaCl:
Find the molar mass of NaCl: Na (22.99 g/mol) + Cl (35.45 g/mol) = 58.44 g/molCalculate the moles of NaCl: 78 g NaCl ÷ 58.44 g/mol = 1.335 moles NaClSince the stoichiometry is one-to-one, the moles of NaCl will equal the moles of AgNO₃ that react:
1.335 moles NaCl = 1.335 moles AgNO₃ consumedFind the molar mass of AgNO₃: Ag (107.87 g/mol) + N (14.01 g/mol) + 3×O (16 g/mol each) = 169.87 g/molCalculate the mass of AgNO₃ consumed: 1.335 moles × 169.87 g/mol = 226.86 grams AgNO₃Therefore, 226.86 grams of AgNO₃ is consumed when 78 grams of NaCl react.
Consider separate 1.0-l gaseous samples of h2, xe, cl2, and o2 all at stp.
a. rank the gases in order of increasing average kinetic energy.
b. rank the gases in order of increasing average velocity.
c. how can separate 1.0-l samples of o2 and h2 each have the same average velocity?
All gases at the same temperature have the same average kinetic energy. The average velocity of gases increases with decreasing molar mass. Thus, 1.0-L samples of O2 and H2 can have the same velocity because velocity is also affected by temperature.
Explanation:The kinetic energy of a gas is determined by its temperature, not by the identity of the gas itself. This is explained by the Kinetic Molecular Theory. Because all four gases are at the same temperature (standard temperature), they have the same average kinetic energy.
However, the average velocity of the gases varies depending upon the molar mass of the gas. The lighter the gas (lower molar mass), the faster it moves. Thus, the order of increasing velocity is Xe < Cl2 < O2 < H2.
To answer part c, the reason why 1.0-L samples of O2 and H2 can each have the same average velocity despite being different substances is because the average velocity of a gas depends not only on its mass, but also the temperature at which it is measured. As these two samples are both at the same temperature, they can have the same average velocity.
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Sea anemones are predatory invertebrates with stinging tentacles that can paralyze many sea animals. The clownfish is immune to the sting of the sea anemone and actually lives among its tentacles. The relationship is mutually beneficial—the clownfish often lures meat-eating animals over to the anemone, and the anemone benefits from the meal. The clownfish often gets to eat leftovers from the anemone’s meal.
When the clown fish is ready to lay eggs, it lays them near a sea anemone. How’s this a reproductive strategy?
The sea anemone protects the clownfish’s eggs from predators.
The sea anemone fertilizes the clownfish’s eggs.
The sea anemone provides nourishment for the clownfish’s eggs.
The sea anemone uses the clownfish’s eggs to lure prey.
The sea anemone lets the clownfish rest on it.
NextReset
Clownfish lay their eggs near sea anemones as a reproductive strategy because the anemones' stinging tentacles protect the eggs from predators.
When clownfish are ready to lay eggs, they do so near a sea anemone to leverage the anemone's natural defenses as part of their reproductive strategy.
Sea anemones have stinging tentacles that can immobilize or deter potential predators. This interaction is a classic example of mutualism, a type of symbiotic relationship between two organisms where both benefit.
For clownfish, laying eggs near the sea anemone means the eggs are protected by the anemone's stinging capabilities, which significantly reduces the likelihood of predators consuming them. The correct answer to how this is a reproductive strategy is that the sea anemone protects the clownfish's eggs from predators.
Although clownfish and anemones do have a mutually beneficial relationship overall, in this specific case, the anemone does not fertilize, nourish the eggs, or use them to lure prey, nor does it provide a resting place for clownfish.
Which of these equations demonstrates energetic coupling in a cell? equation 1: atp + h2o → adp + pi δg1 = –7 kcal/mol equation 2: phosphoenolpyruvate + h2o → pyruvate + pi δg2 = –14.8 kcal/mol equation 3: glucose + pi → glucose-6-phosphate + h2o δg3 = +3.3 kcal/mol equation 4: adp + pi → atp + h2o δg3 = +7 kcal/mol?
Final answer:
Energetic coupling in a cell is demonstrated when the energy from an exergonic reaction, like ATP hydrolysis (Equation 1), is used to drive an endergonic reaction, such as the phosphorylation of glucose (Equation 3). ment.
Explanation:
Energetic coupling is a process where the energy released by an exergonic reaction (such as ATP hydrolysis) is used to drive an endergonic reaction, making the coupled process energetically favorable. To identify energetic coupling, we look for equations that pair an exergonic reaction with an endergonic reaction.
Equation 1: ATP + H2O → ADP + Pi; ΔG1 = –7 kcal/mol. This equation represents the hydrolysis of ATP, an exergonic reaction releasing energy.
Equation 3: glucose + Pi → glucose-6-phosphate + H2O; ΔG3 = +3.3 kcal/mol. This equation represents the endergonic process of phosphorylating glucose, which requires input of energy.
The coupling of ATP hydrolysis (Equation 1) to drive the phosphorylation of glucose (Equation 3) in cellular metabolism demonstrates energetic coupling. Here, the energy released from ATP is used to phosphorylate glucose, a process critical for cellular metabolism and an example of how cells harness energy from exergonic reactions to power endergonic reactions. Such coupling is central to cellular bioenergetics and metabolic pathways.
convert 4540 grams of gold to moles of gold
To calculate moles , we divide mass of the substance given by the molar mass of the substance.
That can be mathematically represented as:
[tex] Number of moles of a substance= \frac{Given mass of a substance}{ Molar mass of substance} [/tex]
Here given mass of substance is 4540 g
Molar mass of the substance is 196 g mol⁻¹
So number of moles can be calculated as:
[tex] Number of moles of a substance= \frac{Given mass of a substance}{ Molar mass of substance} [/tex]
[tex] Number of moles of gold= \frac{4540}{196} [/tex]
So number of moles of gold =23.16 mol