Answer:
2.7 °C.kg/mol
Explanation:
Step 1: Calculate the freezing point depression (ΔT)
The normal freezing point of a certain liquid X is-7.30°C and the solution freezes at -9.9°C instead. The freezing point depression is:
ΔT = -7.30 °C - (-9.9 °C) = 2.6 °C
Step 2: Calculate the molality of the solution (b)
We will use the following expression.
b = mass of solute / molar mass of solute × kilograms of solvent
b = 102. g / (162.2 g/mol) × 0.650 kg = 0.967 mol/kg
Step 3: Calculate the molal freezing point depression constant Kf of X
Freezing point depression is a colligative property. It can be calculated using the following expression.
ΔT = Kf × b
Kf = ΔT / b
Kf = 2.6 °C / (0.967 mol/kg) = 2.7 °C.kg/mol
When taking a measurement with a pH meter, keep the instrument in the ______________ until it is needed. Rinse the pH meter with ______________ and gently pat dry. Place the meter in the sample solution, and record the measurement when the pH __________
Answer:
Storage solution; deionized water; stabilizes.
Explanation:
The pH scale measures the concentration of hydrogen ions in acidic and alkaline solutions.
In chemistry, it literally means power of hydrogen ions and it is a measure of the molar concentration of hydrogen ions in a particular solution, thus specifying the acidity, neutrality or basicity of chemical solutions.
Mathematically, the pH of a solution is given by;
[tex] pH = -log_{10}(H^{+}) [/tex]
Hence, a solution with a pH of 7 is neutral. Also, a solution with a pH below 7 is acidic but basic (alkaline) if it's pH is above 7.
A pH meter can be defined as a scientific instrument or device designed and developed for the measurement of the hydrogen-ion concentration in water-based solutions, in order to determine their level of acidity or alkanility.
When using a pH meter to take a measurement, you should keep it in a storage solution until it is needed. Also, a deionized water should be used to rinse the pH meter and gently pat dry.
Furthermore, the pH meter should be placed in a given sample solution and a reading of the measurement taken when the pH of the solution stabilizes.
Consider an atom that has an electron in an excited state. The electron falls to a lower energy level. What effect does that have on the electron?
A.The electron releases energy in the form of light.
B.The electron absorbs energy in the form of light.
C.The electron retains its energy without any change.
D.The electron transfers its energy to other electrons.
Answer:
c it does not change the energy state
Explanation:
Can someone help me answer this please
Answer:
A) 1.3 × 10⁻⁵ mol/L
Explanation:
Step 1: Write the balanced equation for the solution of AgCl
AgCl(s) ⇄ Ag⁺(aq) + Cl⁻(aq)
Step 2: Make an ICE Chart
AgCl(s) ⇄ Ag⁺(aq) + Cl⁻(aq)
I 0 0
C +S +S
E S S
If we replace the solubility (S) in the Ksp expression, we get,
Ksp = [Ag⁺] [Cl⁻] = S × S = S²
S = √Ksp = √1.8 × 10⁻¹⁰ = 1.3 × 10⁻⁵ mol/L
Which of the following is considered a standard unit of length in the United States?
O square inch
O acre
O cubic yard
O yard
Answer:
Yard . I hope this helped:))
Aqueous hydrochloric acid reacts with solid sodium hydroxide to produce aqueous sodium chloride and liquid water . What is the theoretical yield of sodium chloride formed from the reaction of 0.73g of hydrochloric acid and 1.3g of sodium hydroxide?
Round your answer to 2 significant figures.
i think its 2.0
Why do i think this-If you add 0.73g to 1.3g it comes to 2.0g
There are four different starting molecules that one might use to synthesize the illustrated alkyl halide as the major product using an electrophilic addition reaction. Please draw all four of them.
Answer:
Explanation:
An electrophilic addition reaction occurs when an electrophile attacks a substrate, with the end result being the inclusion of one or many comparatively straightforward molecules along with multiple bonds.
In the given question, the hydrogen bromide provides the electrophile while the bromide is the nucleophile. The mechanism proceeds with the attack of the electrophile on the carbon, followed by deprotonation. This process is continued with a formation of carbocation and the bromide(nucleophile) finally bonds to the carbocation to form a stable product.
The first diagram showcases the possible various starting molecules for the synthesis while the second diagram illustrates their mechanism.
an element E forms a hydride EH3, which contains 90% of E by mass. what is the relative atomic mass ?
Answer:
27 g/mol of E
Explanation:
Note that percentage by mass= mass of each element present. So, since there is 90% of E, there is 90g of E present. By implication, there are 10g of H corresponding to 10%H. Note that there is 100g of EH3
1 moles of E corresponds to 90 g of E
Mole ratio of E: H= 1:3
Thus
Number of moles of H = 10g/ 1g/ mol = 10 moles of H
Since E contains 1/3 the number of moles of H
Number of moles of E = 1/3 × 10 = 3.33 moles of E
Molar mass of E= mass of E/ number of moles of E
Since mass of E = 90 g
Molar mass of E = 90g/3.33 moles
Molar mass of E = 27 g/mol
Round 5578 L to three significant figures.
a. 557 L
b. 558 L
c. 5.58 x 10(3) L
d. 5.58 x 10(-3) L
Answer:
b
Explanation:
The figures of a number that are noteworthy in high accuracy or precision are known as significant figures. They are as follows:
Any digit that isn't zeroAs in 20012 or 64.60007, there are zeros between non-zero numbers.Only use leading zeros when a decimal point is present, such as in 5640.0 or 532.330.If the figure is less than 5, remove it and leave the rest of the number unaffected but if more than 5 add, round it up to 1, and add it to the next figure in the line.From the given information:
To (3) sig. fig: 5578 L = 558 L
g The boiling of water is a Question 4 options: chemical and physical damage chemical change because a gas (steam) is given off chemical change because heat is needed for the process to occur physical change because the water merely disappears physical change because the gaseous water is chemically the same as the liquid
Answer:
physical change because the gaseous water is chemically the same as the liquid
Explanation:
Matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states.
Generally, matter exists in three (3) distinct or classical phases and these are; solid, liquid and gas.
A physical change can be defined as a type of change that only affects the physical form of a chemical substance (matter) without having any effect on its chemical properties. Thus, a physical change would only affect the physical appearance and properties of a chemical substance (matter) but not its chemical properties.
This ultimately implies that, a physical change result in a change of matter from one form or phase (liquid, solid or gas) to another without a corresponding change in chemical composition.
Hence, the boiling of water is considered to be a physical change because the gaseous water is chemically the same as the liquid i.e there isn't any changes in chemical composition of water when boiling.
Select the net ionic equation for the reaction that occurs when magnesium sulfate and nickel(II) nitrate are mixed.
a. Ni2+(aq) + SO4^2- → NISO2 (s) + O2 (g).
b. Mg2+(aq) + 2NO3 (aq) → Mg(NO3)2(s).
c. Mg2+(aq) + NO3- → MgNO3 (s).
d. Mg2+(aq) + SO4^2- (aq) + Ni2+ (aq) + 2NO3- → Mg2+ (aq) + 2NO3 (aq) + NISO4 (s).
e. Ni2+(aq) + SO4^2- (aq) → NISO4 (s).
f. No reaction occurs.
Answer:
No reaction occurs.
Explanation:
The molecular reaction is as follows;
MgSO4(aq) + Ni(NO3)2(aq) ----> Mg(NO3)2(aq) + NiSO4(aq)
We can see from the reaction above that the both products of the reaction are soluble. Recall that a double replacement reaction often yields one insoluble product which separates as a precipitate.
This reaction does not occur since the two products that ought to be obtained are soluble in water.
A hot ballon with mass of 400 kilograms moves across the aky with 3,200 joules of kinetic energy. The velocity of the ballon is
Answer:
4 m/s
Explanation:
formula is v = (KE/.5m)^1/2
there is a calculator
https://www.calculatorsoup.com/calculators/physics/kinetic.php
Determine the mass in grams of 3.27 × 10²¹ atoms of arsenic. (The mass of one mole of arsenic is 74.92 g.)
Explanation:
74.92 g.
(The mass of one mole of arsenic is 74.92 g.
Equilibrium constants for gases can be expressed in terms of concentrations, Kc, or in terms of partial pressures, Kp. Which one of the following statements regarding Kc and Kp is correct?
a. Kc and Kp are equal when all stoichiometric coefficients in the balanced reaction equation equal one.
b. Kc and Kp are equal when the conditions are standard (P= 1 atm, T=298 K)
c. Kc and Kp are equal when the sum of the stoichiometric coefficients for the products equals the sum of the stoichiometric coefficients for the reactants.
d. Kc and Kp can never be equal.
e. Kc and Kp have the same values but different units.
Answer:
c. Kc and Kp are equal when the sum of the stoichiometric coefficients for the products equals the sum of the stoichiometric coefficients for the reactants.
Explanation:
Hello there!
In this case, according to the given information, it turns out firstly necessary for us to write the relationship between Kc and Kp in terms of the temperature and the change in the stoichiometric coefficients:
[tex]Kp=Kc(RT)^{\Delta \nu}[/tex]
Thus, we can see that the Kp=Kc just when Δυ=0, which is the sum of the coefficients of products minus that of reactants; and therefore, the correct answer will be c. Kc and Kp are equal when the sum of the stoichiometric coefficients for the products equals the sum of the stoichiometric coefficients for the reactants.
Regards!
How many milliliters of a 0.40%(w/v) solution of nalorphine must be injected to obtain a dose of 1.5 mg?
Answer:
0.375mL of solution of nalorphine must be injected
Explanation:
A solution of 0.40% (w/v) contains 0.40g of solute (In this case, nalorphine), in 100mL of solution. To obtain 1.5mg of nalorphine = 1.5x10⁻³g of nalorphine are needed:
1.5x10⁻³g * (100mL / 0.40g) =
0.375mL of solution of nalorphine must be injectedHow many moles are in 18.2 g of CO2?
41.4 moles
801 moles
0.414 moles
0 2.42 moles
Answer:
0.414 mole (3 sig. figs.)
Explanation:
Given grams, moles = mass/formula weight
moles in 18.2g CO₂(g) = 18.2g/44g/mole = 0.413636364 mole (calc. ans.)
≅ 0.414 mole (3 sig. figs.)
which effect of long-term environmental change is the driving force behind evolution?
Answer:
climate change
Explanation:
climate change is driving force of evolution because when the climate is changed the animal and human need to adapt to it's natural change.
You pre-weigh a glass vial to hold your sample and find its mass to be 5.010 g. You add your sample to the vial and reweigh it on the same balance and find that the mass has increased to 6.130 g. What is the mass of the sample in grams
When we pre-weigh a glass vial to hold our sample and find its mass to be 5.010 g. Then we add our sample to the vial and reweigh it on the same balance and find that the mass has increased to 6.130 g. The mass of the sample in grams is 1.12 g.
What is mole concept?Avogadro's number is the number of units in one mole of any substance and equals to 6.02214076 × 10²³. The units can be electrons, atoms, ions, or molecules.
No. of moles is defined as a particular no. of particles that we can calculate with the help of Avogadro’s number.
Mass of a particular product is also find out by stoichiometry of a reaction as per the no. of mole given in the reaction.
Mass is generally can be represented by units like Kg, g etc.
Given,
weigh of glass vial = 5.010 g
weigh of glass vial with sample = 6.130 g
Therefore, When we pre-weigh a glass vial to hold our sample and find its mass to be 5.010 g. Then we add our sample to the vial and reweigh it on the same balance and find that the mass has increased to 6.130 g. The mass of the sample in grams is 1.12 g.
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A tank at is filled with of sulfur tetrafluoride gas and of sulfur hexafluoride gas. You can assume both gases behave as ideal gases under these conditions. Calculate the mole fraction of each gas. Round each of your answers to significant digits.
The question is incomplete, the complete question is:
A 7.00 L tank at [tex]21.4^oC[/tex] is filled with 5.43 g of sulfur hexafluoride gas and 14.2 g of sulfur tetrafluoride gas. You can assume both gases behave as ideal gases under these conditions. Calculate the mole fraction and partial pressure of each gas. Round each of your answers to significant digits.
Answer: The mole fraction of sulfur hexafluoride is 0.221 and that of sulfur tetrafluoride is 0.779
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
For sulfur hexafluoride:Given mass of sulfur hexafluoride = 5.43 g
Molar mass of sulfur hexafluoride = 146.06 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of sulfur hexafluoride}=\frac{5.43g}{146.06g/mol}=0.0372mol[/tex]
For sulfur tetrafluoride:Given mass of sulfur tetrafluoride = 14.2 g
Molar mass of sulfur tetrafluoride = 108.07 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of sulfur tetrafluoride }=\frac{14.2g}{108.07g/mol}=0.1314mol[/tex]
Total moles of gas in the tank = [0.0372+ 0.1314] mol = 0.1686 mol
Mole fraction is defined as the moles of a component present in the total moles of a solution. It is given by the equation:
[tex]\chi_A=\frac{n_A}{n_A+n_B}[/tex] .....(2)
where n is the number of moles
Putting values in equation 2, we get:
[tex]\chi_{SF_6}=\frac{0.0372}{0.1686}=0.221[/tex]
[tex]\chi_{SF_4}=\frac{0.1314}{0.1686}=0.779[/tex]
Hence, the mole fraction of sulfur hexafluoride is 0.221 and that of sulfur tetrafluoride is 0.779
Small amounts of Liquid A and Liquid B are sprayed into the air, where they form perfect spheres with a volume of 45.0μL. The diameters of these drops are measured with a high-speed camera, and their surface areas SA and SB calculated.
a. SA will be greater than SB
b. SA will be less than SB
c. SA will be equal to SB
d. It's impossible to predict whether SA or SB will be greater without more information.
d. It's impossible to predict whether SA or SB will be greater without more information.
What is surface area?The surface area of an object is the sum of the areas of all its surfaces. It is typically measured in square units, such as square inches or square centimeters. The formula for the surface area of an object depends on its shape.
The surface area of a sphere is given by the formula 4πr^2, where r is the radius of the sphere. Since the volume of the spheres formed by Liquid A and Liquid B is the same (45.0 μL), their radii will also be the same. Therefore, the surface area of the spheres formed by Liquid A and Liquid B will also be the same.
However, it's important to note that this assumes that the two liquids have the same density and viscosity. If the densities or viscosities of the liquids are different, that could affect the size and shape of the drops, and thus the surface area.
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It's impossible to predict whether SA or SB will be greater without more information. The correct answer is: d.
The surface area of a sphere is given by the formula [tex]4\pi r^2[/tex], where r is the radius of the sphere. Given that the volume of the drops is the same, their radii will be different depending on the density of the liquids. The density of Liquid A and Liquid B will determine their respective masses for a fixed volume, which in turn will affect their radii when forming spheres.
If the densities of Liquid A and B are significantly different, the sphere with the higher density liquid will have a smaller radius and thus a smaller surface area, while the sphere with the lower density liquid will have a larger radius and a larger surface area. Conversely, if the densities are similar, the radii and surface areas may also be similar. Therefore, without more information about the densities of the liquids, we cannot accurately predict whether SA or SB will be greater. Hence The correct answer is: d.
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Compound EX4 reacts with Y2 giving two products: EX Y and XY. Calculate the E- X bond enthalpy if the reaction liberates 243.6 kJ/mol and other bond enthalpies are:
Y-Y 109 kJ/mol,
X-Y 123.1 kJ/mol and
E-Y 290 kJ/mol.
a. 547.7 kJ/mol
b. 60.5 kJ/mol
c. 234.7 kJ/mol
d. 20.6 kJ/mol
e. 176.9 kJ/mol
Answer:
Option B
Explanation:
From the question we are told that:
Equation
[tex]EX_4+Y_2->EX_3Y+XY[/tex]
Bond enthalpies are:
[tex]Y-Y 109 kJ/mol,[/tex]
[tex]X-Y 123.1 kJ/mol[/tex]
[tex]E-Y 290 kJ/mol.[/tex]
Generally the equation for the energy used to break E-X and Y-Y is mathematically given by
[tex]E_2=109+x[/tex]
Therefore
Total Energy Liberated is
[tex]E_T=E_1+E_2[/tex]
[tex]E_T=413.1+109+x[/tex]
[tex]E_T=304.1-x[/tex]
Since
[tex]E_T+E_I[/tex]
Therefore
[tex]304.1-x=243.6[/tex]
[tex]x=60.5kJ/mol[/tex]
Option B
write the formula
fluoride ion
Answer:
F-
Explanation:
Since Fluorine needs one more electron to reach a full octet, it takes in 1 more electron to become an anion. Therefore, with the extra negative charge from the 1 electron, a Fluoride ion has a charge of -1.
Hope this helped!
Answer:
F_
Explanation:
the symbol or formula
is F_
how many 1+ ions would you need to balance with one 2- ion
Answer:
2 ion 1+
Explanation:
Soybeans is used in food production and cooking in 2007 United States produced 3.06 billions bushels of soybeans and 65% of the harvest was used to make soybeans oil
Answer:
1.071
Explanation:
Answer:
Find the percentage of soybeans used for other purposes:
100% − 65% = 35%.
Multiply the result (35%) by the total bushels of soybeans produced:
35
100
=
0.35
.
0.35 × 3.06 billion bushels = 1.071 billion bushels
The amount of soybeans used for other purposes was 1.071 billion bushels.
Explanation:
PLATO
Soap
a. Assume that Crisco is a single triacylglyceride (it is actually a mixture of triacylglycerides) in which all acyl groups are palmitate (palmitic acid = CH,3(CH2)14CO2H). Draw the structure of this triacylglyceride.
b. Show the products that are generated when Crisco and sodium hydroxide react. Use the same assumption as in question a. b. Show the products that are generated when Crisco and sodium hydroxide react. Use the same assumption as in question a.
c. What is the purpose of adding ethanol in the preparation of soap?
Answer:
Explanation:
From the given information:
The structure of the triacylglyceride can be seen in the first image attached below and the products produced as the result of the reaction between Crisco and sodium hydroxide (NaOH) are Glycerol and 3-Palmitic acid as shown in the second image below.
Lastly, the purpose of the addition of ethanol is because water and oils are not miscible. Thus, ethanol has the potential to mix and dissolve in water as well as in oil on a selective partial level. This method aids in the formation of water, soap, salt, and fatty acids from the interaction between fatty acid and sodium hydroxide. As a result, ethanol improves the interaction between the water and the oil. It is less polar to water and aids in the dissolution of nonpolar fats such that sodium hydroxide may react with ethanol.
In the following reaction, Zn is Zn(s) H2SO4(aq) --> ZnSO4(aq) H2(g) A.Reduced B.Oxidized C.This is not a redox reaction D.An oxidizing agent
Answer: The correct option is B) oxidized
Explanation:
Redox reaction is defined as the reaction in which oxidation and reduction take place simultaneously.
The oxidation reaction is defined as the reaction in which a chemical species loses electrons in a chemical reaction. It occurs when the oxidation number of a species increases.
A reduction reaction is defined as the reaction in which a chemical species gains electrons in a chemical reaction. It occurs when the oxidation number of a species decreases.
For the given chemical reaction:
[tex]Zn+H_2SO_4+S\rightarrow ZnSO_4+H_2[/tex]
On the reactant side:
Oxidation number of H = +1
Oxidation number of Zn = 0
Oxidation number of S = +6
Oxidation number of O = -2
On the product side:
Oxidation number of H = 0
Oxidation number of Zn = +2
Oxidation number of S = +6
Oxidation number of O = -2
As the oxidation number of Zn is increasing from 0 to +2. Thus, it is getting oxidized. Similarly, the oxidation number of H is decreasing from +1 to 0. Thus, it is getting reduced.
Hence, the correct option is B) oxidized
Which of the following is true for the percentage yield of a reaction?
Answer:
It is always less than the theoretical yield.
How many atoms are in 7.0 g of Ne?
Answer:
2.11×10²³ atoms.
Explanation:
From the question given above, the following data were obtained:
Mass of Ne = 7 g
Number of atoms =?
Recall:
1 mole of Ne = 6.02×10²³ atoms
1 mole of Ne = 20 g
Thus,
20 g of Ne = 6.02×10²³ atoms
Finally, we shall determine the number of atoms in 7 g of Ne. This can be obtained as follow:
20 g of Ne = 6.02×10²³ atoms
Therefore,
7 g of Ne = (7 × 6.02×10²³) / 20
7 g of Ne = 2.11×10²³ atoms
Thus, 7 g of Ne contains 2.11×10²³ atoms.
Which is a general chemical equation for an exothermic, single-replacement reaction?
A.
AB + CD + energy → AD + CB
B.
AB + C → A + CB + energy
C.
AB + CD → AD + CB + energy
D.
AB + C + energy → A + CB
Answer:
c
Explanation:
it is because the chemical reaction will have the exposure to all the minerals with Microsoft word
The molecular formula of water is H, O. What does it express
Answer:
Firstly, the molecular formula of water would be H2O. Secondly, it expresses the amount of different atoms in the water molecule. In this case, H2 would be two Hydrogen atoms, and O would be 1 Oxygen atom.
Explanation:
Hope this helped!
Answer:
It basically means that water contains 2 atoms of Hydrogen and 1 atom of Oxygen.
It also expresses that the valency of Oxygen is 2 and water has more Hydrogen than OxygenIf the Air Pressure on a mountain Is 0.3 atm what is this value mmHg? 1atm = 760mmHg = 101kPa
Answer:
IS IT MULTIPLE CHOICE
Explanation:
