The freezing points of each of the solutions are as follows;
0.100 m K2S - - 0.558oC
21.5 g of CuCl2 in 4.50 * 102 g water - -2oC
5.5% NaNO3 by mass (in water) - - 2.6oC
What is freezing point?The freezing point is the point at which liquid changes to solid. Let us now look at the freezing point of each solution.
a)
Since;
ΔT = K m i
K = 1.86 oC m-1
m = 0.100 m
i = 3
ΔT = 1.86 oC m-1 * 0.100 m * 3 = 0.558oC
Freezing point = 0oC - 0.558oC = - 0.558oC
b) Number of moles of CuCl2 = 21.5 g/134.45 g/mol = 0.16 moles
molality = 0.16 moles/0.45 Kg = 0.36 m
ΔT = K m i
ΔT = 1.86 oC m-1 * 0.36 m * 3 = 2oC
Freezing point = 0oC - 2 = -2oC
c) Number of moles of NaNO3 = 5.5g/85 g/mol = 0.065 moles
molality of the solution = 0.065 moles/0.0945 Kg = 0.69 m
ΔT = 1.86 oC m-1 * 0.69 m * 2 = 2.6oC
Freezing point = 0oC - 2.6oC = - 2.6oC
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If 4.80 mol Ca mixed with 2 mol N2, which is the limiting reactant? 3Ca (s) + N2 (g) Ca3N2 (s)
A solution was found to have a 15.6 % transmittance at 500 nm, its wavelength of maximum absorption, using a cell with a path length of 5.00 cm. Calculate the absorbance of the solution in a 1.00 cm cell at 500 nm. A. 0.161 B. 69.0 C. 0.0312 D. 4.04
For the absorbance of the solution in a 1.00 cm cell at 500 nm is mathematically given as
A’ = 0.16138
What is the absorbance of the solution in a 1.00 cm cell at 500 nm?Absorbance (A) 2 – log (%T) = 2 – log (15.6) = 0.8069
Generally, the equation for the Beer’s law is mathematically given as
A = ε*c*l
0.8069 = ε*c*(5.00 )
ε*c = 0.16138 cm-1
then for when ε*c is constant
l’ = 1.00
A’ = (0.16138 cm-1)*(1.00 cm)
A’ = 0.16138
In conclusion, the absorbance of the solution in a 1.00 cm cell at 500 nm is
A’ = 0.16138
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Please Help Me Answer Numbers 7, 9, 10, and 11!
How does the number of lone pairs affect the bonding pairs?
A. They repel more strongly than the bonding pairs, pushing the bonding pairs closer together.
B. They occur between the bonding pairs, pushing them to opposite sides of the central atom.
C. It does not affect them.
D. The pull the bonding pairs, widening the angle between them.
Answer:
A. They repel more strongly than the bonding pairs, pushing the bonding pairs closer together.
Explanation:
Lone pairs are in simple terms just pairs of electrons on the atom. Negative does not attract negative so it repels from the bonds. I put it in the most simple terms possible. Like with magnets north and north don't attract. Same concept
The elements A and B combine to produce two differenr compounds. A3B and AB2. if 0.18 mol of A3B has a mass of 17.7g and 0.18 mol of Ab2 has a mass of 11.3g calculate the molar masses of both elemts a and b.
Taking into account the definition of a system of linear equations and molar mass, the molar masses of elements A and B are 26.778 [tex]\frac{g}{mole}[/tex] and 17.998[tex]\frac{g}{mole}[/tex] respectively.
System of linear equationsA system of linear equations is a set of two or more equations of the first degree, in which two or more unknowns are related.
Solving a system of equations consists of finding the value of each unknown so that all the equations of the system are satisfied. That is to say, the values of the unknowns must be sought, with which when replacing, they must give the solution proposed in both equations.
Definition of molar massThe molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.
The molar mass of a compound (also called Mass or Molecular Weight) is the sum of the molar mass of the elements that form it (whose value is found in the periodic table) multiplied by the number of times they appear in the compound.
Molar masses of elements A and BBeing the molar masses of the compounds:
A₃B: [tex]\frac{17.7 g}{0.18 moles} =[/tex] 98.33 [tex]\frac{g}{mole}[/tex]AB₂: [tex]\frac{11.3 g}{0.18 moles} =[/tex] 62.77 [tex]\frac{g}{mole}[/tex]and considering the definition of molar mass of a compound, the system of equations to be solved is
[tex]\left \{ {{3mA + mB=98.33\frac{g}{mole} } \atop {mA + 2mB=62.77\frac{g}{mole} }} \right.[/tex]
where mA and mB are the molar masses of elements A and B respectively.
There are several methods to solve a system of equations, it is decided to solve it using the substitution method, which consists of clearing one of the two variables in one of the equations of the system and substituting its value in the other equation.
Isolating the variable mB from the first equation:
mB= 98.33 [tex]\frac{g}{mole}[/tex] - 3mA
and substituting in the second equation, you get:
mA + 2× (98.33 [tex]\frac{g}{mole}[/tex] - 3mA)=62.77[tex]\frac{g}{mole}[/tex]
Solving:
mA + 2× 98.33 [tex]\frac{g}{mole}[/tex] - 2×3mA=62.77[tex]\frac{g}{mole}[/tex]
mA + 196.66 [tex]\frac{g}{mole}[/tex] - 6mA=62.77[tex]\frac{g}{mole}[/tex]
mA - 6mA=62.77[tex]\frac{g}{mole}[/tex] - 196.66 [tex]\frac{g}{mole}[/tex]
(-5)mA= - 133.89 [tex]\frac{g}{mole}[/tex]
mA= (- 133.89 [tex]\frac{g}{mole}[/tex] )÷ (-5)
mA= 26.778 [tex]\frac{g}{mole}[/tex]
Remember that mB= 98.33 [tex]\frac{g}{mole}[/tex] - 3mA, replacing the value of mA:
mB= 98.33 [tex]\frac{g}{mole}[/tex] - 3×(26.778 [tex]\frac{g}{mole}[/tex])
mB= 80.334 [tex]\frac{g}{mole}[/tex]
mB= 17.998 [tex]\frac{g}{mole}[/tex]
Finally, the molar masses of elements A and B are 26.778 [tex]\frac{g}{mole}[/tex] and 17.998[tex]\frac{g}{mole}[/tex] respectively.
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Use the periodic table to answer the questions below.
Which diagram shows the correct electron
configuration for nitrogen (N)?
atomic mass for N = 7
electron configuration: 1s²2s²2p³
orbital diagram:
↑↓ ↑↓ ↑ ↑ ↑
1s² 2s² 2p³
dk how to do this :)
Answer:
2Mg, 2 02, MgO
A student boils water in an electric kettle for 20 minutes. Using the same mains supply, he wants to reduce the boiling time of water. To do so, should he increase or decrease the length of the heating element? Justify your answer.
Answer:
The student needs to increase the length of the heating element
Explanation:
Increasing the length of the heating elements helps to increase the surface area of the heating elements which allows for more water to come in contact with the heating element
A heterogeneous mixture is:
A. composed of atoms bonded together.
B. composed of different parts that are indistinguishable in their color, texture, or appearance.
C. composed of only one type of element.
D. composed of different parts that are distinguishable in their color, texture, or appearance.
Answer:
B
Explanation:
A mixture in which the composition is not uniform throughout.
Same thing letter B says.
5 pounds of zinc is mixed into 10 pounds of copper to produce brass alloy. Which metal is the solute for this solution
Answer:
Zinc with copper is Brass, Zinc is alloyed with Lead and Tin to make solder.
2. Which substance has definite volume and weight, but not a definite
shape?
B
A. ice
wood
C. gasoline
D. steam
Answer:
A solid has definite volume and shape, a liquid has a definite volume but no definite shape, and a gas has neither a definite volume nor shape. The change from solid to liquid usually does not significantly change the volume of a substance
Explanation:
no explanation
Determine the hybridization about O in CH3oh
Answer:
c
Explanation:
lol
A hydrogen bond can occur between:
A. Two oxygen atom surrounded by hydrogens.
B. Two hydrogen atoms on different molecules.
C. The two hydrogen atoms on a water molecule.
D. A hydrogen from one molecule and an oxygen from another molecule.
Answer:
A
Explanation:
it can occur between two hydrogen bonds
dk how to do this help please
Explanation:
hello
the answer is b
O or oxygen has 16 molar mass and C or carbon has 12
so CO2 or carbon dioxide=(2×O)+C=(2×16)+12=46
What is the definition of specific heat?
A. The heat needed to raise the temperature of 1 g of a substance
1°C
B. The temperature change between the melting and boiling points of
a substance
C. The heat required to break the molecular bonds within a
substance
OD. The total amount of energy contained within 1 mole of a
substance
SUBMIT
Answer:
A: The heat needed to raise the temperature of 1 g of a substance1°C
Explanation:
Specific heat is the temperature required to raise the temperature of the unit mass of a given substance. With that being said, of all options A: protrays the definition perfectly.
Side Note: I hope this helps feel free to let me know if you have any other questions.
find the molarity of 131 g Ba(NO3)2 dissolved in 750.0 water
Answer:
6.68 x 10^-4
Explanation:
131g ÷ 261.337g/mol = 0.5012685 moles
0.5012685 moles ÷ 750.0 liters =
0.5012685÷ 750.0=0.000668358
6.68 x 10^-4
HCl(?) + H2O(?) → H3O+(?) + Cl-(?)
What is the phase label on Cl-?
Answer:
H30,+ion is known as Hydroniom Ion
Explanation:
brain ly ----
everyday
brainless this answer is correct
How can you tell that Mercury is not a gas giant?
A.
because it is dense and rocky
B.
because of where it orbits the sun
C.
because it has only one moon
D.
because it has no ring system
Answer:
The answer to this question is A.
hope it helps :)
Water is a _____ molecule, which gives it many of its unique properties, including its ability as a universal solvent.
Answer:
The answer is Polar.
Explanation:
Because polar has many unique properties.
need help with this ty
Answer:
The correct answer to first question is C
I only know this one.
Explanation:
PLEASE MARK ME BRAINLIEST IF MY ANSWER IS CORRECT PLEASE
I also kno wtge answer to question 7 is A
Explain your reasoning for your formula prediction for Ba+2 and S-2. A neutral molecule requires equal numbers of cations and anions. Atoms will not combine unless their ions have an equal but opposite charge. The total charge of cations plus anions must equal zero. all of the above
Answer:
BaS would be a stable neutral molecule!
Reason:- All of the above.
Explanation:
In order to form a neutral molecule it's necessary to balance their charge first, The given components i.e. Ba2+(cation) and S2-(anion) have equal and opposite charges, when they combine they form predominantly ionic compound i.e. Sulphur partly shares it's 2 electrons with Barium and forms Barium sulphide.
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HELPPPPP
54.5 g of Ca(NO3)2 was used to create a 1.5 M solution. What is the volume of the solution in ml?
We have already been introduced to solutions. Several chapters ago molarity (M) was introduced. Molarity is measured in moles per liter, or mol/L. A 0.30 M NaCl solution means that there is 0.30 mol NaCl in every liter of solution.
Often chemists have to make solutions; so, doing the calculations necessary to make a certain amount of solution become second nature.
For example:
Make 250 mL of a 0.30 M NaCl solution.
To make the solution we need to calculate the amount of NaCl to dissolve to make 250 mL of solution.
start with 250 mL
The solution is made by adding 4.38 g NaCl to a 250-mL volumetric flask. About 100 mL of water are added and when all the NaCl dissolves water is added up to the line on the volumetric flask.
But molarity is not the only unit we use; so, we need to be able to convert between different units...
Common units of concentration include
<==> <==><==>
% wt.
% vol
molarity (M)
molality (m)
mol fraction
That is, the mol fraction of "a" is the number of moles of "a" present divided by the total number of moles of material in the solution (including the solvent).
There is no simple formula for converting from one concentration unit to the next. In general the first step is to pick a convenient sample size. Then work to change each part of the concentration unit to the new unit. Do not try to do the conversion all at once.
For example,
HCl comes in bottles marked 37 % HCl by weight. The density of the solution is 1.200 g/cm-1. What is the molarity of the solution?
A conveneint sample size is 100 g of solution; convenient because 100 g x 37% = 37 g HCl.
This is the key...you must know the definitions for all the concentration terms
First, convert number of grams of HCl in your sample to number of moles in your sample (the 100 g of solution).
Second, convert g of solution to L of solution.
Third, divide moles by liters and you have molarity.
What is the molality of this solution?
Going from M to m. Since the concentration is in M a convenient sample size is 1 L.
OK, so the first conversion is not a conversion...there are 12 mol HCl present in 1 L of solution.
The second conversion is not as easy as it first appears. Let's use the density of the solution to perform a conversion from volume to mass.
This is NOT the mass that is used in molality. We just determined the mass of the solution; molality uses the mass of the SOLVENT!
The solution is made of a solvent and a solute. So, the mass of solvent can be found by subtracting the mass of the solute from the mass of the solution.
Question 6 (2 points) If 100.0 mL ethyl alcohol weighs 78.5 g, determine the volume in litres occupied by 1.59 kg of ethyl alcohol. Answer Instructions:
The volume in litres occupied by 1.59 Kg of ethyl alcohol given the data from the question is 2.03 L
How to determine the mole of 78.5 g of ethyl alcohol Mass of ethyl alcohol = 78.5 gMolar mass of ethyl alcohol = 46.07 g/molMole of ethyl alcohol =?Mole = mass / molar mass
Mole of ethyl alcohol = 78.5 / 46.07
Mole of ethyl alcohol = 1.7 mole
How to determine the mole of 1.59 Kg of ethyl alcohol Mass of ethyl alcohol = 1.59 Kg = 1.59 × 1000 = 1590 gMolar mass of ethyl alcohol = 46.07 g/molMole of ethyl alcohol =?Mole = mass / molar mass
Mole of ethyl alcohol = 1590 / 46.07
Mole of ethyl alcohol = 34.5 moles
How to determine the new volume Initial volume (V₁) = 100 mL = 100 / 1000 = 0.1 LInitial mole (n₁) = 1.7New mole (n₂) = 34.5 moles New Volume (V₂) =.?V₁ / n₁ = V₂ / n₂
0.1 / 1.7 = V₂ / 34.5
Cross multiply
1.7 × V₂ = 0.1 × 34.5
Divide both side by 1.7
V₂ = (0.1 × 34.5) / 1.7
V₂ = 2.03 L
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calculate the pressure in atmospheres of 1.92 moles of helium gas in a 10.0L container at 25C
The pressure in atmospheres of the given mole and volume of helium gas is 4.7atm.
Given the data in the question;
Amount of helium; [tex]n = 1.92mol[/tex]Volume of the gas; [tex]V = 10.0L[/tex]Temperature; [tex]T = 25^0C = 298.15K[/tex]Pressure in atmosphere; [tex]P = \ ?[/tex]
Ideal Gas LawThe Ideal gas law emphasizes on the behavior of a hypothetical ideal gas. It states that pressure P multiply by volume V is equal to moles times temperature and the universal gas constant.
It is expressed;
[tex]PV = nRT[/tex]
Where P is pressure, V is volume, n is the amount of substance, T is temperature and R is the ideal gas constant.( [tex]R = 0.08206Latm/molK[/tex] ).
To determine the pressure in atmosphere, we substitute our values into the expression above.
[tex]PV = nRT\\\\P = \frac{nRT}{V} \\\\P = \frac{1.92mol\ *\ 0.08206Latm/molK\ *\ 298.15K}{10.0L} \\\\P = \frac{46.975Latm}{10.0L}\\\\P = 4.7atm[/tex]
Therefore, the pressure in atmospheres of the given mole and volume of helium gas is 4.7atm.
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Draw the reactants using the drawing tool. Keep in mind that one molecule of nitrogen has two bonded atoms, and one molecule of hydrogen has two bonded atoms.
The formation of ammonia gas involves reacting hydrogen gas and nitrogen gas in a mole ratio of 3 to 1. as shown below:
[tex]N_2 + 3H_2 \rightarrow 2NH_3[/tex]What is the equation of the formation of ammonia?Ammonia gas is formed from the reaction between nitrogen gas and hydrogen gas.
Three moles of hydrogen gas will react with 1 mole of nitrogen gas to form 2 moles of ammonia gas.
The equation of the reaction is given below as:
[tex]N_2 + 3H_2 \rightarrow 2NH_3[/tex]
Therefore, the formation of ammonia gas involves reacting hydrogen gas and nitrogen gas in a mole ratio of 3 to 1.
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How many moles of water are produced from the decomposition of 3.4g of hydrogen peroxide, H2O2
Answer:
0.1 moles
Explanation:
3.4 g * (1 mol/34 g) = 0.1 moles
The reaction Na3PO4 + 3HCl → 3NaCl + H3PO4 produces 42.7 g of NaCl. How many grams of Na3PO4 are needed?
Answer:
14.23
Steps given below in the picture
I hope my answer helps you.
1. Which statements about activation energy are true? Select all that apply.
A)Activation energy is determined by the strength of the bonds that must be formed.
B)Activation energy is determined by the strength of the bonds that must be broken.
C)Activation energy is determined by the charge of the bonds that must be formed.
D)Activation energy is determined by the charge of the bonds that must be broken
E)Activation energy is the minimum quantity of energy that the reactants must possess
in order to undergo a specified reaction.
F)Activation energy is the maximum quantity of energy that reaction products generate
after undergoing a specified reaction.
The true statements about activation energy are as follows:
Activation energy is the minimum quantity of energy that the reactants must possess in order to undergo a specified reaction.Activation energy is determined by the strength of the bonds that must be broken.What is activation energy?Activation energy is the minimum amount of energy that reactants in a chemical reaction must possess so as to get converted into products.
In a chemical reaction, reactants form products, hence, certain bonds must be broken in the reactant molecules to form the products.
The energy needed to break the bonds of the reactants is known as activation energy.
Therefore, the true statements about activation energy are as follows:
Activation energy is the minimum quantity of energy that the reactants must possess in order to undergo a specified reaction.Activation energy is determined by the strength of the bonds that must be broken.Learn more about activation energy at: https://brainly.com/question/11334504
hard water contains calcium and magnesium ions. one way to soften water is to add sodium phosphate. Write complete and net ionic equations for the reaction of these two alkaline earth metals with aqueous sodium phosphate
Explanation:
The photo is the net ionic equation for the Calcium ions
The net ionic equation for the reaction is [tex]3Ca^{+2} + 2PO^{-3}_2----- > Ca_3(PO_4)_2[/tex]
What is chemical reaction?A chemical reaction is the chemical transformation of one set of chemical substances into another.
When chemical bonds between the atoms are formed or broken, chemical reactions occur.
The substances that initiate a chemical reaction are known as reactants, and the substances that result from the reaction are known as products.
Plants grow, start producing fruit, and decompose to become compost for new plants through chemical reactions.
The reaction for the given scenario is,
[tex]3Ca^{+2} + 2PO^{-3}_2----- > Ca_3(PO_4)_2[/tex]
Thus, above mentioned is the chemical reaction.
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When potassium and chlorine form a chemical compound, the atoms
a. become less stable, and covalent bonds are
formed
b. become more stable, and covalent bonds are
formed
c. become less stable, and ionic bonds are
formed
d. become more stable, and ionic bonds are
formed
Answer:
D
Explanation:
Potassium metal and chlorine gas combine to form potassium chloride. The balanced equation is 2K (s) + Cl2 (g)→2KCl (s) There are two chlorine atoms on the left-hand side (LHS) and one chlorine atom on the right-hand side (RHS).
