Pellets of calcium chloride are spread on a sidewalk covered in water that is 36°c. under which circumstance will the calcium chloride dissolve faster? it rains, increasing the amount of water on the sidewalk. sand is sprinkled on the sidewalk. the water cools to a temperature of 33°c. people walking on the sidewalk crush the calcium chloride pellets. the air pressure increases as the weather changes.
Answer:
people walking on the sidewalk crush the calcium chloride pellets.
Explanation:
When calcium chloride pellets are crushed with feet it increases the surface area of the calcium chloride. As the surface area increase the number of collision between the reactant molecules increases. Here the reactant molecules are calcium chloride ions and water molecules. In the process of dissolution the calcium chloride ions get hydrated by the dipoles of the water molecules. As the frequency of collision increases it lowers the activation energy or threshold barriers to start a reaction.
A .100 molal aqueous solution of which compound has the lowest freezing point
ΔT = Kf · b(solution) · i.
Kf - the freezing point depression constant.
i - Van 't Hoff factor. Because dissociate on one cation and one anions, sodium hydroxide has i = 2, other molecules has covalent bonds (i = 1, do not dissociate on ions).
Because molality and the freezing point depression constant are constant, greatest freezing point lowering is solution with highest Van 't Hoff factor.
Answer: NaOH
Explanation:
*QUICK*
Measuring the level of lead in drinking water is the job of _____.
A.) a physical chemist B.) a biochemist C.) an analytical chemist
Answer:
Measuring the level of lead in drinking water is the job of an analytical chemist.
Explanation:
The work of analytical chemists is to analyse the chemical properties and nature of the substance.
They have to perform different experiments using instruments and then conclude about the nature of the sample, chemical properties of the sample, toxicology, concentration and other properties of the samples and then the analytical chemists should give a detailed report on the measurements or analysis he or she has carried out.
So the measuring of lead in drinking water forms under the measurement of toxicology of water as lead is toxic on reaction with water so it is the job of analytical chemists only.
Answer:
Definitely an analytical chemist. Because the substance has to be analyzed to look for those chemicals and toxins.
Explanation:
Use the periodic table to determine the electron configuration for aluminum (al) and arsenic (as) in noble-gas notation.
Answer: Electronic configuration of
1. Aluminium is [tex][Ne]3s^23p^1[/tex]
2. Arsenic is [tex][Ar]4s^23d^{10}4p^3[/tex]
Explanation: To write the electronic configuration of the elements in the noble gas notation, we first count the total number of electrons and then write the noble gas which lies before the same element.
For Aluminium:Atomic number = 13
Total number of electrons = 13
Noble gas which lies before this element is Neon (Ne).
Neon has 10 electrons, rest 3 electrons are filled in 3s and 3p sub-shells.
Electronic configuration of Aluminium becomes [tex][Ne]3s^23p^1[/tex]
For Arsenic:Atomic number = 33
Total number of electrons = 33
Noble gas which lies before this element is Argon (Ar).
Neon has 18 electrons, rest 15 electrons are filled in 4s , 3d and 4p sub-shells.
Electronic configuration of Arsenic becomes [tex][Ar]4s^23d^{10}4p^3[/tex].
Answer:
C and the other one is A
Explanation:
trust me
What letter represents the enthalpy of reaction?
Answer : The letter represents the enthalpy of reaction is, 'H'
Explanation:
Enthalpy of a reaction : Enthalpy of a reaction is defined as the energy change which takes place when the reactants go to the products.
Enthalpy of a reaction is represented as, [tex]\Delta H[/tex]. In this, 'H' represent the enthalpy.
When the enthalpy of reaction is positive that means the heat is absorbed during the reaction.
When the enthalpy of reaction is negative that means the heat is released during the reaction.
That means, when the enthalpy of reaction is negative then the energy is released and the reaction will be exothermic reaction.
when the enthalpy of reaction is positive then the energy is absorbed and the reaction will be endothermic reaction.
Hence, the letter represents the enthalpy of reaction is, 'H'
What is the empirical formula of a substance that is 53.5% C, 15.5% H, 31.1% N?
How many grams of nitroglycerin are needed to produce 25.0 grams of CO2
If the average salinity of seawater is 35 ppt,how many grams of dissolved salts will 500 grams of seawater contain
How many phases of matter are present in whipped cream?
which is a saturated solution?
1)40g NH4Cl in 100g water at 50 degrees celcius
2)2g SO2 in 100g water at 10 degrees celcius
3)52g KCL in 100g water at 80 degrees celcius
4)120g KI in 100g water at 20 degrees celcius
The saturated solution among the provided options is the one with 52g KCl in 100g water at 80 degrees Celsius, because KCl's solubility limit at this temperature is about 51g per 100g of water, and this solution marginally exceeds that amount. Hence correct option C.
To identify which option represents a saturated solution, one must refer to the solubility curves for each substance at the given temperatures. A saturated solution is one where the maximum amount of solute has dissolved in the solvent at a specific temperature. If more solute is added to a saturated solution, it will not dissolve and will remain as a precipitate. Conversely, if the amount of solute in a solution is less than the solubility limit at that temperature, the solution is considered unsaturated.
Looking at the options given by the student:
For NH₄Cl, its solubility at 50 degrees Celsius is approximately 62g per 100g of water, so if there's 40g NH₄Cl in 100g of water at 50 degrees Celsius, it is an unsaturated solution since it is less than the solubility limit.
For SO₂, its solubility at 10 degrees Celsius is much higher than 2g per 100g of water, implying that this is an unsaturated solution as well.
With KCl, the solubility at 80 degrees Celsius is about 51g per 100g of water. Since 52g KCl is mentioned, this solution is just over the saturation point, making it a saturated solution.
Lastly, KI's solubility at 20 degrees Celsius is around 140g per 100g of water, so a solution of 120g KI in 100g water is unsaturated.
Therefore, the correct answer is the one with 52g KCl in 100g water at 80 degrees Celsius, as it is the only saturated solution listed.
The molecular formula for glucose is c 6 h 12 o 6 . what would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?
The hydrogen generated in a reaction is collected over water and occupies 425 ml at 18 c and 742 torr. what is the volume of the dry h2
A(n) ________ is a group of atoms that determines many of the properties of an organic molecule.
Write the formula for the polyatomic ion of ba3(po4)2: express your answer as an ion. express single charges as [+], not [1+]
The polyatomic ion in Ba3(PO4)2 is PO4^3-. To construct the formula for an ionic compound with polyatomic ions, the formula for the polyatomic ion is enclosed in parentheses if it is needed in more than one quantity, and the subscript representing the quantity is placed outside the parentheses.
Explanation:The formula for the polyatomic ion in Ba3(PO4)2 is PO43-.
The whole compound Ba3(PO4)2 is composed of barium ions (Ba2+) and phosphate ions (PO43-).
Since barium has a charge of 2+ and phosphate has a charge of 3-, for the charges to balance in Ba3(PO4)2, we need three barium ions to balance the charge of two phosphate ions.
Each phosphate ion is a group of one phosphorus atom and four oxygen atoms carrying a net charge of 3-.
When writing the formula for a compound with more than one polyatomic ion, the formula of the polyatomic ion must be enclosed in parentheses with the appropriate numerical subscript outside the parentheses.
This subscript indicates the number of polyatomic ions in the compound.
Hence, the compound name calcium phosphate is represented by the formula Ca3(PO4)2, where three calcium ions balance the charge of two phosphate ions.
Yes or no: will a precipitate form when solutions of ba(no3)2 and koh are mixed?
Which fact is NOT true about gravity?
Question 24 options:
Gravity depends on distance.
Gravity depends on weight.
Gravity depends on mass.
The force of gravity between two objects will never be 0.
The fact that 'Gravity depends on weight' is not true. Gravity doesn't depend on weight; instead, weight is actually a result of the gravitational force. Gravity does depend on mass and distance: bigger mass and closer distance result in stronger gravitational force.
Explanation:The statement 'Gravity depends on weight' is NOT true about gravity. Gravity does not depend on weight; instead, it is actually the other way around - weight is the force that gravity exerts on an object. Additionally, gravity does depend on mass and distance - the larger the mass and the closer the objects, the stronger the force of gravity. However, it's important to remember that the force of gravity will not be zero except in the theoretical case where the objects are at infinite distance from one another.
Weight is actually dependent on gravity because it's the force that gravity exerts on an object. So, in this case, weight depends on gravity, not gravity on weight.
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What is a pure substance that cannot be chemically broken down into simpler substances?
1. For the balanced equation shown below, how many moles of O2 will react with 0.3020 moles of CO2?
2C2H5OH + 6O2 → 4CO2 + 6H2O
A. 0.151 moles O2
B. 0.201 moles O2
C. 0.302 moles O2
D. 0.453 moles O2
2. How much heat is required to convert 74 grams of ice at -4 C into 74 grams of water at 52 C?
Use the information below:
Hf= 334 J/g
A. 606 J
B. 24,716 J
C. 4000 J
D. 41, 406 J
5.
What happens in a condensation reaction?
cross-linking of monomers
head-to-tail joining of monomers
side-by-side joining of monomers
substitution of a halogen on monomers
Answer:
B: head to tail joining of monomers
Explanation:
If you don't reply with an actual answer I will report it and you will be reported and itll give me back my points
1.If I have 4 moles of a gas at a pressure of 5.6 atm and a volume of 12
liters, what is the temperature?
2.If I have an unknown quantity of gas at a pressure of 121.6 kPa, a
volume of 31 liters, and a temperature of 87 0C, how many moles of
gas do I have?
3.If I contain 3 moles of gas in a container with a volume of 60 liters and
at a temperature of 400 K, what is the pressure inside the container?
4.If I have 7.7 moles of gas at a pressure of 0.09 atm and at a temperature
of 56 0C, what is the volume of the container that the gas is in?
5.If I have 17 moles of gas at a temperature of 67 0C, and a volume of
88.89 liters, what is the pressure of the gas?
Use Dalton’s Law of Partial Pressures and Grahams law of effusion to solve
the following problems:
6.At a certain temperature, molecules of methane gas, CH4 have an average
velocity of 0.098 m/s. What is the average velocity of carbon dioxide
molecules at this same temperature?
7.7.) Find the relative rate of diffusion for the gases chlorine, Cl2 and ethane,
C2H6.
8.495 cm3 of oxygen gas and 877 cm3 of nitrogen gas, both at 25.0 °C and
114.7 kPa, are injected into an evacuated 536 cm3 flask. Find the total
pressure in the flask, assuming the temperature remains constant.
explain why it is often milder in areas such as coastal Maryland while areas such as Kansas or Iowa have more extremes in temperature?
Final answer:
Coastal areas like Maryland have milder climates due to the moderation by nearby ocean water, which has a stable temperature that influences the air temperature over land. In contrast, inland areas such as Kansas and Iowa experience more extreme temperatures due to their distance from the ocean's moderating effects and greater influence from continental air masses.
Explanation:
The location of an area relative to the coast significantly influences its climate due to the effects of oceanality and continentality. Coastal Maryland, being near the Atlantic Ocean, experiences milder conditions because the temperature of ocean water remains relatively stable throughout the year, moderating the air temperature over the land. In contrast, inland areas such as Kansas and Iowa are subject to more extreme temperatures due to their distance from the ocean's moderating influence, leading to significantly warmer summers and colder winters.
Ocean water has a high heat capacity, which means it absorbs and releases heat more slowly than land, resulting in a smaller range of temperature fluctuations. This heat inertia is why coastal areas tend to have more moderated climates. For example, airflow from the ocean keeps San Francisco's climate mild and more constant throughout the year, while Salt Lake City, which is an inland city at approximately the same latitude, experiences greater temperature variation.
In summary, coastal regions are influenced by the temperature of the nearby ocean, which changes little with the seasons. This results in a milder climate with less variation between summer and winter temperatures. Conversely, inland regions are more subject to continental air masses, leading to a larger range in temperatures and more extreme seasonal conditions.
The ksp of tin(ii) hydroxide, sn(oh)2, is 5.45 × 10-27. calculate the molar solubility of this compound.
The molar solubility of a compound can be calculated using its solubility product constant, Ksp. For tin(II) hydroxide, the Ksp is used in conjunction with the stoichiometry of its dissolution in water to find the maximum amount that can dissolve per liter of solution.
Explanation:The solubility product constant, or Ksp, is a measure of how much of a particular ionic compound can dissolve in a solution. It's used to calculate the molar solubility, which is the maximum amount of the compound that can dissolve per liter of solution. In this case, the Ksp of tin(II) hydroxide, Sn(OH)2, is given as 5.45 × 10-27.
To calculate the molar solubility, we use the expression for the dissolution of Sn(OH)2 in water: Sn(OH)2 (s) <==> Sn2+ (aq) + 2OH- (aq) Due to the stoichiometry of the reaction, the concentration of Sn2+ is 'x' and that of OH- is '2x'. The KSP expression is: Ksp = [Sn2+][OH-]^2 = x * (2x)^2 = 4x^3. Setting this to the given Ksp value, we get: 5.45 × 10-27 = 4x^3. Solving for 'x' gives us the molar solubility of Sn(OH)2.
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What is the molarity of a NaOH solution if 15.0 mL of the solution is neutralized by 38.5 mL 0.150 M H3PO4 solution?
The blank solution used to calibrate the spectrophotometer is 10.0 mL of 0.2 M Fe(NO3)3 diluted to 25.0 mL with 0.1 M HNO3. Why is this solution preferred to simply using de-ionized water for the calibration?
The blank solution used to calibrate the spectrophotometer contains 0.2 M Fe(NO3)3 and 0.1 M HNO3 to reflect the composition of the actual samples and to maintain consistent ionic strength and acidity, leading to more accurate and reliable measurements.
Explanation:When calibrating a spectrophotometer, it is preferred to use a blank solution that is reflective of the matrix of the samples being measured. In this case, the blank solution contains not just de-ionized water but also 0.1 M HNO3 and 0.2 M Fe(NO3)3 diluted accordingly. This approach is preferred because it accounts for the absorption of the solvent and any potential interaction with the analyte.
The use of HNO3 in the calibration blank maintains a consistent ionic strength and acidity as in the samples, which can affect the absorbance readings. This method reduces background noise and leads to more accurate and reliable measurements when comparing the blank to the actual samples containing Fe³+ ions.
The blank solution for calibration includes Fe(NO₃)₃ and HNO₃ to match the sample matrix, reducing calibration errors caused by matrix effects. De-ionized water fails to replicate the sample's chemical environment.
The blank solution used to calibrate the spectrophotometer is 10.0 mL of 0.2 M Fe(NO₃)₃ diluted to 25.0 mL with 0.1 M HNO₃. This solution is preferred over de-ionized water because it closely matches the matrix of the actual samples being measured, ensuring that any absorbance readings due to the matrix itself are accounted for. This reduces the possibility of matrix effects, thus providing a more accurate calibration for the spectrophotometer. This ensures more accurate spectrophotometer readings.
De-ionized water lacks the chemical environment of the sample solutions, which could lead to calibration errors. By using a matrix-matched blank, the spectrophotometer can be properly calibrated, accounting for interactions between Fe(NO₃)₃ and HNO₃ that might affect absorbance.
Which substance produced in the laboratory is used as a post exposure preventative measure against rabies?
The formation of a solid when two liquids are mixed indicates a reaction.
a. True
b. False
A soda has a volume of 560 ml and a density of 3.2g/ml. what is the mass?
Answer: Mass of the substance is 1.792 kg
Explanation: Density of a substance is defined as the mass contained per unit volume.
[tex]Density=\frac{mass}{volume}[/tex]
Given:
Volume = 560 ml
Density = 3.2 g/ml
[tex]Mass=Density\times volume[/tex]
[tex]Mass=3.2g/ml\times 560ml=1792g[/tex]
Mass of the substance is 1792 g or 1.792 kg.
What does the suffix -ide indicate when naming an ionic compound?
Which of the following best explains why you sanded the copper wire before burning it?
to create less friction between the copper and the tongsto make sure that copper metal was exposed on the surface of the wireto make the copper wire flammableto weaken the copper wire so it would be more reactive
Answer: Option (b) is the correct answer.
Explanation:
When copper wire is place into the atmosphere or anywhere then there is possibility that some oxide layer or impurity must have deposited over its surface.
So, when we sanded copper wire then these impurities get removed and copper metal gets exposed onto the surface.
Thus, we can conclude that you sanded the copper wire before burning it to make sure that copper metal was exposed on the surface of the wire.
Answer:
B. to make sure that copper metal was exposed on the surface of the wire
Explanation:
Right on Edgen.
Which type of society survives mainly by foraging for food?
A. Hunter-gatherer
B. Agrarian
C. Industrial
D. Pastoral
Answer :
D. Agrarian
Explanation: