Answer:
- 0.454 °C
Explanation:
From the given information:
The mass of KCl = 10 grams
The molar mass of KCl = 74.55 g/mol
The molality can be calculated as:
[tex]Molality \ m = \dfrac{mass \ of \ KCl \times 1000}{molar \ mass \ of \ KCl \times 1100.0}[/tex]
[tex]Molality \ m = \dfrac{10 \ g \times 1000}{74.55 \ g/mol \times 1100.0}[/tex]
Molality m = 0.1219 M
For freezing point depression;
[tex]\Delta T_R = i \times k_f \times m[/tex]
The van't Hoff's Factor (i) for KCl = 2
The molar depression of freezing point constant [tex]k_f[/tex] = 1.86° C/m
∴
[tex]\Delta T_R = 2 \times 1.86 \times 0.1219[/tex]
[tex]\mathbf{\Delta T_R = 0.454^0\ C }[/tex]
However, the freezing point of water is known to be = 0°C
Therefore, the freezing point of the solution
= 0 °C - 0.454 °C
= - 0.454 °C
Which question must be answered to complete the table below?
A 3-column table with 3 rows. Column 1 is labeled alpha decay with entries alpha particles, plus 2 and low. Column 2 is labeled Beta Decay with entries no entry, electron negative 1 positron positive 1, and medium. Column 3 is labeled Gamma decay with entries gamma rays, 0 and high.
a. What kind of shielding will block beta decay?
b. What is the penetrating power of beta decay?
c. What kind of particles are produced by beta decay?
d. How massive are the particles in beta decay?
Answer:
c
Explanation:
For something to be considered
dead, it used to do what?
Answer:
breathe,eat, and drink i guess
How did changing from a light drizzle to a downpour affect the river and the sediment un it
Answer:
The velocity of the river increased.
There was more erosion in the stream.
The type of sediment that moved changed.
Explanation:
Answer:
The river increased its slope.
The volume of the river decreased.
The velocity of the river increased.
There was more erosion in the stream.
The type of sediment that moved change
Explanation:
A 25.00-mL aliquot of a nitric acid solution of unknown concentration is pipetted into a 125-mL Erlenmeyer flask and 2 drops of phenolphthalein are added. The above sodium hydroxide solution (the titrant) is used to titrate the nitric acid solution (the analyte). If 12.75 mL of the titrant is dispensed from a burette in causing a color change of the phenolphthalein, what is the molar concentration of the nitric acid solution? (Show all steps for calculating the answer.)
Answer: 0.0611 M HNO3
Answer:
0.0611M of HNO3
Explanation:
The concentration of the NaOH solution must be 0.1198M
The reaction of NaOH with HNO3 is:
NaOH + HNO3 → NaNO3 + H2O
1 mole of NaOH reacts per mole of HNO3.
That means the moles of NaOH used in the titration are equal to moles of HNO3.
Moles HNO3:
12.75mL = 0.01275L * (0.1198mol / L) = 0.0015274 moles NaOH = Moles HNO3.
In 25.00mL = 0.025L -The volume of the aliquot-:
0.00153 moles HNO3 / 0.025L =
0.0611M of HNO3Find the density of a liquid that has a mass of 24 grams and a volume of 6 ml.
Answer:
4
Explanation:
24/6 is 4.
Answer:
Mathematically: D = m/v. If you know what liquid you have, you can look up its density in a table. Once you know that, all you have to do to find the mass of the liquid is to measure its volume. Once you know density and volume, calculate mass using this relationship: mass = density • volume.
Explanation:
An aqueous solution of Pb(NO3)2 is made by placing 275 g of solid Pb(NO3)2 into a volumetric flask and adding water to the 1.00 L mark (assume that 775g of water has been added to achieve this total solution volume). (Assume MW of Pb(NO3)2 = 331g/mole) A) What is the molarity (M) of this solution? B) What is the molality (m) of this solution? C) What is the mass % of Pb(NO3)2 in this solution? D) What is the mole fraction of Pb(NO3)2 present in this solution?
Answer:
A) 0.831 M
B) 1.07 m
C) 26.2%
D) 0.0189
Explanation:
A) First we convert the mass of Pb(NO₃)₂ to moles:
275 g ÷ 331 g/mol = 0.831 mol Pb(NO₃)₂Then we divide it by the total volume (1.00 L) to calculate the molarity:
0.831 mol / 1.00 L = 0.831 MB) We convert the grams of water to kilograms:
775 g / 1000 = 0.775 kgThen we divide the Pb(NO₃)₂ by the kilograms of water:
0.831 mol / 0.775 kg = 1.07 mC) We divide the mass of Pb(NO₃)₂ by the total mass of the solution:
[tex]\frac{gPb(NO_{3})_{2}}{gPb(NO_{3})_{2}+gH_{2}O}[/tex] *100% [tex]=\frac{275}{275+775}[/tex] * 100% = 26.2%D) We calculate the moles of water:
775 g H₂O ÷ 18g/mol = 43.1 mol H₂OThen we divide the Pb(NO₃)₂ moles by the total number of moles:
[tex]\frac{0.831}{0.831+43.1}[/tex] = 0.0189A 500. mL gas sample is collected over water at a pressure of 740 mmHg and 25.0 °C. What is the volume of the dry gas at STP?
Answer:
Volume of dry gas at STP = 0.432 liters or 432 ml
Explanation:
Given:
Pressure (P) = 740 mmHg - 24 mmHg = 716 mmHg
Temperature (t) = 25 degrees C + 273 K = 298 K
500 ml = 0.5 l
Find:
Volume of dry gas at STP
Computation:
[P1][V1] / T1 = [P2][V2] / T2
[716][0.5] / 298 K = [760][ x Liters] / 273 K
x = 0.432 Liters
Volume of dry gas at STP = 0.432 liters or 432 ml
Is nuclear fission exothermic or endothermic? Explain your answer.
Answer:
Exothermic
Explanation:
Nuclear fission means splitting, so there is a lot of energy being released.
Question 1 of 10
What is technology?
A. An understanding of something new.
B. The steps that engineers go through to create a product.
C. Something created using science for use by society.
D. A method that is used to solve problems,
SUBMIT
Answer:
C.
Explanation:
You can use the series of elimination for this. First, you look at A. Technology is not an understanding of something new, so we cross that out. Second, you look at B. Technology isn't a series of steps, so we can mark that one off. Third, you look at C. Technology is something created using science for use by society, so we can keep that in mind. Lastly, we check D. Technology doesn't match up to the definition, so we can cross that one out. The answer that would make the most sense would be D.
Question 14 (1 point)
Calculate the molarity of a solution made by dissolving 15.25 g lithium chloride (Lici)
in 250 mL of solution
61 M LICI
2
1.4 M LICI
5
0.36 M LICI
18
0.061 M Lici
0.0014 M LICI
Answer:
Molarity = 1.4 M
Explanation:
Given data:
Mass of LiCl = 15.25 g
Volume of solution = 250 mL (250/1000 = 0.25 L)
Molarity of solution = ?
Solution:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
Now we will calculate the number of moles of LiCl.
Number of moles = mass/molar mass
Number of moles = 15.25 g/ 42.39 g/mol
Number of moles = 0.36 mol
Molarity:
Molarity = 0.36 mol / 0.25 L
Molarity = 1.4 M (M= mol/L)
A plant uses carbon dioxide and water to form food and oxygen. Why is this a chemical change?
Answer:
The plant uses carbon dioxide and water to make an entirely new chemical hence chemical change.
Explanation:
Plants create their own 'food', they turn carbon dioxide water and sunlight to create starch and glucose..
Answer:
The properties of carbon dioxide and oxygen are different.
Explanation:
im taking the exam right now and Im pretty sure it's D The properties of carbon dioxide and oxygen are different.
Two elements in the same period have the same number of _____ _____ in their electron clouds.
Answer:
outer electrons
Explanation:
Answer:
Energy levels
Explanation:
A block of lead weighs 11.3 grams. How many atoms of lead are in this sample?
• Use 6.022 x 1023 mol
for Avogadro's number.
Answer:
To get the number of atoms in this sample, we first need the number of moles of lead in 11.3 grams
Number of moles of Lead:
Molar mass of lead = 207 grams / mol
Number of moles = given mass / molar mass
Number of moles = 11.3 / 207
Number of moles = 0.05 moles
Number of atoms of lead in 11.3 gram sample:
Number of atoms = Number of moles * avogadro's number
Number of atoms = 0.05 * 6.022 * 10²³
Number of atoms = 5 * 10⁻² * 10²³ * 6.022
Number of atoms = 30.11 * 10²¹
11.3 g block of lead contains 3.29×10²² atoms
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.022×10²³ atoms. Thus,
1 mole of lead = 6.022×10²³ atoms
Recall:
1 mole of lead = 207 g
Thus,
207 g of lead = 6.022×10²³ atomsWith the above information in mind, we can obtain the number of atoms in 11.3 g block of lead as illustrated below:
207 g of lead = 6.022×10²³ atoms
Therefore,
11.3 g of lead = (11.3 × 6.022×10²³) / 207
11.3 g of lead = 3.29×10²² atomsThus, 11.3 g block of lead contains 3.29×10²² atoms
Learn more: https://brainly.com/question/9758372
An increase in temperature results in A) a decrease in the required activation energy while the reaction rate remains constant. B) an increase in reaction rate due to a decrease in the kinetic energy of the reactants. C) an increase in the rate of reaction because reactant molecules collide with greater energy. D) an increase in both the reaction rate and activation energy due to increased kinetic energy.
Answer:
C) an increase in rate of reaction because reactant molecules collide with greater energy
Explanation:
Temperature is one of the factors that affect the rate of a reaction. The rate of a reaction increases with an increase in temperature and vice versa. When the temperature of a reaction increases, the kinetic energy of the reactant molecules increases causing them to react at a faster rate.
The reactant molecules respond to an increase in temperature by colliding at a faster rate due to an increased kinetic energy between the reactant molecules.
27. A compound has a mass of 2.6632 10 2 g/mol. The number of significant figures in this mass
is —
A. 2
B. 4
C. 5
D. 7
Answer:
its b
B. 4
Explanation:
I NEED HELP ASAP
1.Compare and contrast starch, cellulose, and glycogen. Include the monomers, function, and what type of organism they are found?
2. Describe the relationship between DNA and the structure of proteins. How might a change in the order of nucleotides result in a non-functional protein?
ANYTHING WILL HELP...WILL GIVE A BRAINLY
Answer:
the second on is, Changing the sequence of nucleotides in the DNA molecule can change the amino acids in the final protein, leading to protein malfunction. If insulin does not function correctly, it might be unable to bind to another protein (insulin receptor).
the first one is, These three polysaccharides differ in their glycosidic linkages and their functions too. Starting from the cellulose which is the monomer of beta glucose and is found in plant cell wall only. While Starch and Glycogen act as the carbohydrate reserve in plants and animals respectively. Though their chains have slight differences at the branching point, which is described below.
Explanation:
hope it helps
If a central atom of a molecule only has two electron domains, what is the bond angle associated with the molecule?
120o
180o
90o
109.5o
Answer:
I think it's C.90º
Explanation:
Answer:
180o
Explanation:
It is 180 degrees because the central atom is the atom in the middle of two electrons. Think about it like a straight line, a straight line is equal to 180 degrees. One electron connected to the central atom will be 90 degrees and if there's another electron, it will be 180 degrees.
Hope this helps:)
The osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant . Suppose the osmotic pressure of a certain solution is measured to be at an absolute temperature of . Write an equation that will let you calculate the molarity of this solution. Your equation should contain only symbols. Be sure you define each symbol other than . Your equation: Definitions of your symbols:
Answer:
c = π / R × T
Explanation:
The osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant R . Suppose the osmotic pressure of a certain solution is measured to be 22 atm at an absolute temperature of 353 K. Write an equation that will let you calculate the molarity c of this solution. Your equation should contain only symbols. Be sure you define each symbol other than R.
Step 1: Given data and definition of the symbols
Osmotic pressure (π): 2.2 atmMolarity of the solution (c): ?Ideal gas constant (R): 0.08206 atm.L/mol.KAbsolute temperature (T): 353 KStep 2: Write an equation that will let you calculate the molarity of this solution, in terms of symbols
The osmotic pressure is a colligative property that can be calculated using the following expression.
π = c × R × T
We can rearrange this expression to calculate the molarity of the solution.
c = π / R × T
36.8 g of CuSO4(s) was added to water to prepare a 2.00 L solution. What is the
concentration of CuSO4 in molarity?Molar mass of CuSO4 = 159.62 g/mol
A. 18.4 M
B. 1.84 M
C. 0.231 M
D. 0.115
Answer:
Option D. 0.115 M
Explanation:
The following data were obtained from the question:
Mass of CuSO4 = 36.8 g
Volume of solution = 2 L
Molar mass of CuSO4 = 159.62 g/mol
Molarity of CuSO4 =..?
Next, we shall determine the number of mole in 36.8 g of CuSO4.
This can be obtained as shown below:
Mass of CuSO4 = 36.8 g
Molar mass of CuSO4 = 159.62 g/mol
Mole of CuSO4 =.?
Mole = mass /Molar mass
Mole of CuSO4 = 36.8 / 159.62
Mole of CuSO4 = 0.23 mole
Finally, we shall determine the molarity of the CuSO4 solution as illustrated below:
Mole of CuSO4 = 0.23 mole
Volume of solution = 2 L
Molarity of CuSO4 =..?
Molarity = mole /Volume
Molarity of CuSO4 = 0.23 / 2
Molarity of CuSO4 = 0.115 M
Therefore, the molarity of the CuSO4 solution is 0.115 M.
Which of the following is a common sign that a chemical change has occurred?
Answer:
C a chemical has become a different color
Explanation:
is it a chemical change when water turns to ice? or to water vapor? no because it can easily change back.
it's not A obviously
I just explained why it's not B
and again it's obviously not D
It's C because once you change the color of something you can most likely not change it back (cake batter, stained glass) making it a chemical change
A buffer contains significant amounts of ammonia and ammonium chloride.
Required:
a. Write an equation showing how this buffer neutralizes added aqueous acid (HCl).
b. Write an equation showing how this buffer neutralizes added aqueous acid (KOH).
A buffer system has been the salt solution that has been able to avoid the change in the pH with the addition of acid or base to the solution.
What is the effect of acid and base on buffer?The acid has been comprised of the hydrogen ion, and react with the base with the formation of salt, thereby limit the change in pH.
The addition of acid to the buffer solution has been given as:
[tex]\rm HCl+NH_3\;\leftrightharpoons\;NH_4Cl[/tex]
The base addition to the buffer reacts with the acid part of the buffer and forms salts to resist the change in pH.
The addition of the base, KOH to the buffer solution has been given as:
[tex]\rm KOH+NH_4^+\;\leftrightharpoons\;K^+\;+\;NH_3\;+\;H_2O[/tex]
Learn more about buffers, here:
https://brainly.com/question/24188850
Consider the reaction pathway graph below.
Which statement best describes this graph?
This is an exothermic reaction with a positive ΔHrxn.
This is an exothermic reaction with a negative ΔHrxn.
This is an endothermic reaction with a positive ΔHrxn.
This is an endothermic reaction with a negative ΔHrxn.
Answer:
This is an endothermic reaction with a positive ΔHrxn.
Explanation:
From the question given above, we can see clearly that the energy of the product (Hp) is greater than the energy of the reactant (Hr). This simply means that the reaction is endothermic as the enthalpy change (ΔH) for the reaction will be positive.
Enthalpy change (ΔH) = Heat of product (Hp) – Heat of reactant (Hr)
ΔH = Hp – Hr = positive
NOTE: A reaction with positive enthalphy change (ΔH) is termed endothermic reaction.
Answer:
C
Explanation:
edg 2020
Which pair of elements will form a covalent bond?
describe the structure and function of gamma rays
Answer:
A gamma ray is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves and gives off the highest photon energy. The energy spectrum of gamma rays can be used to identify the decaying radionuclides using gamma spectroscopy.
Explanation:
How does an anion form?
A. An anion forms when a stable atom loses one or more neutrons.
B. An anion forms when a stable atom loses one or more protons.
C. An anion forms when a stable atom gains one or more electrons.
D. An anion forms when a stable atom loses one or more electrons.
There are exaclty 640 acres in one square mile. How many square meters are in 2.2 acres?
Answer:
8,903.09 square meters
Explanation:
Doing a quick search online we can see that there are exactly 4046.86 square meters in a single acre (1 acre). Therefore, we can simply use the rule of three to calculate the total amount of square meters in 2.2 acres. We do this by multiplying 2.2 acres by 4046.86 square meters and then dividing by 1 acre to solve for x.
1 acre <=====> 4046.86 square meters
2.2 acres <====> x
(2.2 * 4046.86) / 1 = x
8903.09 / 1 = x
8,903.09 = x
Finally, we can see that there are 8,903.09 square meters in 2.2 acres.
A sample of sodium bicarbonate is placed in an evacuated container at allowed to reach equilibrium. What will be the total pressure?
Complete Question
Sodium carbonate, Na2CO3(s), can be prepared by heating sodium bicarbonate, NaHCO3(s).
2NaHCO3(s) ------> Na2CO3(s) + CO2(g) + H2O(g) Kp = 0.23 at 100oC
If a sample of NaHCO3 is placed in an evacuated flask and allowed to achieve equilibrium at 100oC, what will the total gas pressure be?
Answer:
The value is [tex]P_T = 0.959 \ atm [/tex]
Explanation:
From the question we are told that
The equation is
[tex]2NaHCO_3_{(s)} \rightarrow Na_2CO_3_{(s)} + CO2_{(g)} + H2O_{(g)}[/tex]
Generally the equilibrium partial pressure is mathematically represented as
[tex]K_p = P_{CO_2} + P_{H_2O}[/tex]
Here
[tex] P_{CO_2} \ and \ P_{H_2O}[/tex] are partial pressures of [tex] CO_2 \ and \ H_2O [/tex] gases
Note: when writing the formula for equilibrium partial pressure we consider only the gas in the reaction
Let assume that
[tex]P_{CO_2} = a[/tex]
Generally [tex]P_{CO_2} = P_{H_2O}[/tex] since they are both products of the reaction
So
[tex]K_p = a^2 [/tex]
From the question we are told that [tex]K_p = 0.23 [/tex]
So
[tex] 0.23= a^2 [/tex]
=> [tex] a = \sqrt{0.23} [/tex]
=> [tex] a = \sqrt{0.23} [/tex]
=> [tex] a = 0.4796 \ atm [/tex]
So
[tex]P_{CO_2} = 0.4796 \ atm[/tex]
and
[tex]P_{H_2O} = 0.4796 \ atm [/tex]
So the total pressure is
[tex]P_T = 0.4796 + 0.4796[/tex]
=> [tex]P_T = 0.959 \ atm [/tex]
Which of the following elements has the largest atomic radius? Bromine, Barium, Magnsium, Zinc
Answer:
Atomic radii vary in a predictable way across the periodic table. As can be seen in the figures below, the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus, helium is the smallest element, and francium is the largest.
Explanation:
help pls
Which process of sedimentary rock formation occurs last?
cementation
compaction
deposition
erosion
Answer:
Compaction.
Explanation:
All the others are before this.
Rahul and Manav each were given a mixture of iron filings and sulphur powder. Rahul heated the mixture strongly and a new substance was formed. Write three points of difference between the two.Required to answer.
Answer:
sure
Explanation:
The substance formed after heating the mixture of that of Rahul is caleed a compound. Whereas, Manav's mixture still remains in its current stae that is a heterogeneous mixture.
The compound formed is in black in color whereas the mixture is a mix of brownish-red and yellow.
The compound is a homogeneous mixture whereas the mixture is a heterogenous mixture because of its uneven distribution.
