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
The weighted average of the mass numbers of all the isotopes that occur in nature for particular element is the average atomic number true or false
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.
A 2.00 g sample of a bromine oxide (brxoy) is converted to 2.94 g of agbr. all the bromine in the original oxide compound ends up in the agbr (molar mass for agbr = 187.8). determine the empirical formula of the bromine oxide.
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.
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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:
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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How many grams of nitroglycerin are needed to produce 25.0 grams of CO2
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?
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'
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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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
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.
In glycolysis, one molecule of glucose containing 6 carbons is converted to two molecules of ________ containing 3 carbons each. this reaction also yields two molecules of _______ and two molecules of _______.
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:
Which type of society survives mainly by foraging for food?
A. Hunter-gatherer
B. Agrarian
C. Industrial
D. Pastoral
Answer :
D. Agrarian
Explanation:
Yes or no: will a precipitate form when solutions of ba(no3)2 and koh are mixed?
The compound diborane (b2h6) was at one time considered for use as a rocket fuel. its combustion reaction is b2h6(g) + 3 o2(â) â 2 hbo2(g) + 2 h2o(â) the fact that hbo2, a reactive compound, was produced rather than the relatively inert b2o3 was a factor in the discontinuation of the investigation of the diborane as a fuel. what mass of liquid oxygen (lox) would be needed to burn 106.3 g of b2h6?
To burn 106.3 g of diborane (B₂H₆), 368.64 g of liquid oxygen (LOX) would be required. This is calculated based on the stoichiometry of the balanced chemical combustion reaction.
Explanation:To calculate the mass of liquid oxygen (LOX) needed to burn 106.3 g of diborane (B₂H₆), we must first use the balanced chemical equation for the combustion of diborane:
B₂H₆ (g) + 3 O₂ (g) → 2 HBO₂ (g) + 2 H₂O (l)
From the equation, we can see that 1 mole of B₂H₆ reacts with 3 moles of O₂. First, determine the molar mass of B₂H₆ which is (2 × 10.81) + (6 × 1.008) = 27.7 g/mol. Now, divide the given mass of B₂H₆ by its molar mass to get the number of moles of B₂H₆:
106.3 g B₂H₆ × (1 mol B₂H₆/27.7 g) = 3.84 moles of B₂H₆
Now calculate the moles of O₂ required using the stoichiometry of the reaction (3 moles of O₂ per mole of B₂H₆):
3.84 moles of B₂H₆ × 3 moles O₂/1 mole B₂H₆ = 11.52 moles O₂
Finally, calculate the mass of O₂ using the molar mass of O₂ which is (2 × 16.00) = 32.00 g/mol:
11.52 moles of O₂ × 32.00 g/mol = 368.64 g of O₂
So, 368.64 g of LOX would be needed to burn 106.3 g of diborane (B₂H₆).
What is the empirical formula of a substance that is 53.5% C, 15.5% H, 31.1% N?
Actions of the non-valence electrons, diluting the force of the attraction between nucleus and valence electrons is called
How does recycling wood products help maintain the supply of forestland for a longer period of time?
A. Recycling increases the consumption of new wood.
B. Recycling increases the cost of new wood.
C. Recycling reduces the supply of new wood.
D. Recycling reduces the demand for new wood.
Recycling reduces the demand for new wood is correct
Answer:
D
Explanation:
A(n) ________ is a group of atoms that determines many of the properties of an organic molecule.
The formation of a solid when two liquids are mixed indicates a reaction.
a. True
b. False
What is the chemical formula of the salt produced by the neutralization of nitic acid calcium hydroxide?
Calcium nitrate is the chemical formula of the salt produced by the neutralization of nitic acid calcium hydroxide.
What is salt?Sodium chloride (NaCl), a mineral component important to health of humans and animals as well as business. To differentiate it from a family of chemical compounds known as salts, the crystalline type halite, meaning rock salt, is often referred to as common salt.
Table salt, which is widely used as a condiment, is fine-grained as well as of high purity. Small amounts of potassium aluminosilicate, tricalcium phosphate, and magnesium silicate are added to guarantee that such a hygroscopic compound remains free-flowing while exposed to the atmosphere. Calcium nitrate is the chemical formula of the salt produced by the neutralization of nitic acid calcium hydroxide.
Therefore, calcium nitrate is the chemical formula of the salt produced by the neutralization of nitic acid calcium hydroxide.
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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
If the average salinity of seawater is 35 ppt,how many grams of dissolved salts will 500 grams of seawater contain
an example of an empirical formula
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:
What is a pure substance that cannot be chemically broken down into simpler substances?
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?