When 42.5 g of benzamide (C7H7NO) are dissolved in 500 g of a certain mystery liquid X, the freezing point of the solution is 6.40 °C less than the freezi point of pure X. Calculate the mass of iron(III) nitrate (Fe(NO3)3 that must be dissolved in the same mass of X to produce the same depression in freezing point.
Answer:
21.3g of Fe(NO₃)₃ are required to produce the same depression in freezing point of solution.
Explanation:
Freezing point depression is a colligative property which indicates, in determined mixture, the freezing point of solution is lower that the freezing point of the solvent, according the amount of solute.
Formula is: ΔT = Kf . m . i
Kf is the cryoscopic constant, which is particular for each solvent. We do not have that data, so we need to find it out in order to solve the question:
ΔT = Freezing point of pure solvent - Freezing point of solution.
This data is known → 6.40°C
m, means molality, moles of solute in 1kg of solvent. Let's get the moles of benzamide: 42.5 g . 1mol / 121g = 0.351 moles
m = 0.351 mol / 0.5kg = 0.702 m
As benzamide is an organic compound i, = 1. i are the number of ions dissolved in solution. Let's find out Kf:
6.40°C = Kf . 0.702 m . 1
6.40°C /0.702m = 9.11 °C/m.
Let's go to the next question.
ΔT is the same → 6.40°C
But this is, an inorganic salt, a ionic salt: Fe(NO₃)₃ → 1Fe³⁺ + 3NO₃⁻
For this case, we have 1 mol of Iron(III) and 3 nitrates, so i = 4
Let's replace data: 6.40°C = 9.11 °C/m . m . 4
6.40°C / (9.11 m/°C . 4) = 0.176 m
This data represents that, in 1 kg of solvent we have 0.176 moles of nitrate.
Mass of solvent X required in this case is 0.500 kg, so, the moles that are contained are: 0.500 kg . 0.176 mol/kg = 0.088 mol
Let's determine the mass of salt: 0.088 mol . 241.85g /1mol = 21.3 g
The bond angle for methane is the angle determined by two consecutive hydrogen atoms and the central carbon atom.
a. True
b. False
Answer:
a. True
Explanation:
The bond angle for methane is the angle determined by two consecutive hydrogen atoms and the central carbon atom.
Methane, a tetrahedron has the structural formula:
H
|
H - C - H
|
H Methane, CH4
The bond angle is the angle between the H-C-H atoms and is 109.5degrees.
Given the setup of the equilibrium constant expression, a reaction that has a high equilibrium constant will "favor" the products
True
False
Answer:
for points
Explanation:
loll
Which of the following statements is false?
a. This class discussed four physical states of matter
b. An atom is the smallest particle of an element that still contains properties of the original element.
c. Gases can be colorless or colored
d. Mass is the measure of the earth’s gravitational attraction of a body
e. A pure substance has a fixed composition.
Answer:
d. Mass is the measure of the earth’s gravitational attraction of a body
This is FALSE. Mass is the measure of matter than an object contains.
Explanation:
b. An atom is the smallest particle of an element that still contains properties of the original element.
This is True
c. Gases can be colorless or colored
This is True
d. Mass is the measure of the earth’s gravitational attraction of a body
This is FALSE. Mass is the measure of matter than an object contains.
e. A pure substance has a fixed composition.
This is True.
explain why vapour pressure increases with increasing temperature.
The sink-float method is often used to identify the type of glass material found at crime scenes by determining its density.Several different types of glass of known density are placed into solutions of varying densities. Determine whether each glasspiece will sink, float, or do neither when immersed in the given solution.Glass that will sinkGlass that will floatGlass that will not sink or floatalkali zinc borosilicate with a density of2.57 g/mL in a solution with a densityof 2.46 g/mLsoda borosilicate with a density of 2.27 g/mLin a solution with a density of 2.62 g/mLalkali strontium with a density of 2.26 g/mL ina solution with a density of 2.34 g/mLpotash borosilicate with a density of2.16 g/mL in a solution with a densityof 2.16 g/mLpotash soda lead with a density of 3.05 g/mLin a solution with a density of 1.65 g/mLAnswer Bankterms of usecontac
Answer:
Glass that will sink: alkali zinc borosilicate with a density of2.57 g/mL in a solution with a density of 2.46 g/mL; potash soda lead with a density of 3.05 g/mL in a solution with a density of 1.65 g/mL
Glass that will float: soda borosilicate with a density of 2.27 g/mL in a solution with a density of 2.62 g/mL; alkali strontium with a density of 2.26 g/mL in a solution with a density of 2.34 g/mL
Glass that will not sink or float: potash borosilicate with a density of2.16 g/mL in a solution with a density of 2.16 g/mL
Explanation:
The density of an object is a ratio of the mass (or quantity of matter in the object) to its volume.
Mathematically, density = mass/ volume.
The more dense an object, the higher will be its dense. Density can be thought of as a comparison of how heavy objects having the same are. Objects with a higher density, are heavier than objects with a lower density. For example, between equal volumes of air and water, water is heavier.
The density of solid object will determine whether it will float, sink or neither float nor sink in a given liquid. The conditions for floating of objects in a liquid is given as follows:
Density of solid > Density of liquid : solid will sink
Density of solid = Density of liquid : solid will neither sink nor float
Density of solid < Density of liquid : solid will float
Using the above criteria to analyze the given glass materials in their respective liquids:
Glass that will sink: alkali zinc borosilicate with a density of2.57 g/mL in a solution with a density of 2.46 g/mL; potash soda lead with a density of 3.05 g/mL in a solution with a density of 1.65 g/mL
Glass that will float: soda borosilicate with a density of 2.27 g/mL in a solution with a density of 2.62 g/mL; alkali strontium with a density of 2.26 g/mL in a solution with a density of 2.34 g/mL
Glass that will not sink or float: potash borosilicate with a density of2.16 g/mL in a solution with a density of 2.16 g/mL
100 POINTS!!!!
Sydney made the largest s'more when camping with 70g of marshmallows, 50g of graham cracker and 100g of chocolate. To find the percent composition of the chocolate, which equation would she use?
Question 1 options:
100g/120g*100
100g/220g*100
220g/100g*100
120g/100g*100
100g/220g*100 is the correct answer- I took the test
Answer:
answer:
given;
total gram=70+50+100=220g
total gram of chocolate=100g
percentage composition of chocolate=total gram of chocolate/total gram ×100%
=100g/220g ×100 is your answer
Which term is used to describe the variety
of inheritable traits in a species?
Ecosystem diversity
Genetic diversity
Natural selection
Species diversity
So, Ecosystem Diversity is a term that describes how different habitats of organisms are. For example, the fact that our planet has deserts, tundras but also estuaries is a sign of the diversity of its ecosystems. Species diversity refers to the number of different species that inhabit a specific ecosystem or the whole biosphere; the more, the better for species diversity. Genetic diversity is the term we are looking for; it means the variation in genes (usually in one species) that leads to different inheritable traits (in members of the same species). For example eye color is an inheritable trait that showcases genetic diversity since there are many genes that determine a different color such as brown, blue, green etc. (even though the environment plays a role too). Finally, natural selection is a theory about the survival of the fittest due to competition. It relates to inheritable traits and their diversity but it does not describe them.
Which of the following intermolecular forces is the strongest?
A. Hydrogen bonding
B. Van der Waals forces
C. Dipole-dipole attractions
D. Induced dipole attractions
SUBMIT
Answer:
A. Hydrogen Bonding
Explanation:
Answer:
Hydrogen bonding
Explanation:
because it has the highest electronegative force
When would a cell use Active Transport? Mark all that apply.
a. When the cell needs to move a compound down its concentration gradient.
b. When the cell needs to move a compound against its concentration gradient.
c. When the cell needs to move a polar compound.
d. When the cell needs to move a nonpolar compound.
e. When the cell needs to move an ion.
Answer:
Option B, When the cell needs to move a compound against its concentration gradient.
Explanation:
A cell uses active transport when it has to transport substances against the concentration gradient across its membrane.
In active transport additional energy is used (generally provided by energy molecules like ATP) to push the substance across any membrane from low concentration side to high concentration side.
Option B is correct
Which best describes an element?
a pure substance
a type of a mixture
a pure compound
an impure substance
Answer:
A.) pure substance
Explanation:
edge 2021
A ground state hydrogen atom absorbs a photon of light having a wavelength of 93.7 nm.93.7 nm. What is the final state of the hydrogen atom? Values for physical constants can be found in the Chempendix.
Answer:
5
Explanation:
Given that the formula is;
1/λ= R(1/nf^2 - 1/ni^2)
λ = 93.7 nm or 93.7 * 10^-9 m
R= 1.097 * 10^7 m-1
nf = ?
ni = 1
From;
ΔE = hc/λ
ΔE = 6.63 * 10^-34 * 3* 10^8/93.7 * 10^-9
ΔE = 21 * 10^-19 J
ΔE = -2.18 * 10^-18 J (1/nf^2 - 1/ni^2)
21 * 10^-19 J = -2.18 * 10^-18 J (1/nf^2 - 1/ni^2)
21 * 10^-19/-2.18 * 10^-18 = (1/nf^2 - 1/1^2)
-0.963 = (1/nf^2 - 1)
-0.963 + 1 = 1/nf^2
0.037 = 1/nf^2
nf^2 = (0.037)^-1
nf^2 = 27
nf = 5
Calculate the [H+]
and pH of a 0.000295 M
butanoic acid solution. Keep in mind that the a
of butanoic acid is 1.52×10-5
[H⁺]=6.696 x 10⁻⁵
pH = 4.174
Further explanationGiven
The concentration of 0.000295 M (2.95 x 10⁻⁴ M) butanoic acid solution
Required
the [H+] and pH
Solution
Butanoic acid is the carboxylic acid group. Carboxylic acids are weak acids
For weak acid :
[tex]\tt [H^+]=\sqrt{Ka.M}[/tex]
Input the value :
[H⁺]=√1.52 x 10⁻⁵ x 2.95 x 10⁻⁴
[H⁺]=6.696 x 10⁻⁵
pH = - log [H⁺]
pH = - log 6.696 x 10⁻⁵
pH = 5 - log 6.696
pH = 4.174
1. How many moles are in 230. Grams of SO2?
2. How many molecules are in 30.5 moles of lithium nitrate?
3.59 mol
1.836 x 10 ²⁵ molecules
Further explanationGiven
230 g SO2
30.5 moles LiNO3
Required
moles and molecules
Solution
mol = mass : molar mass
1 mol = 6.02 x 10²³ particles(molecules, atoms, ions)
1. 230 g x 1 mol/64,066 g =3.59 mol
2. 30.5 moles x 6.02 x 10 ²³ molecules / 1 mol = 1.836 x 10 ²⁵ molecules
empirical formulas for C2N2
empirical formulas for C6H6
empirical formulas for C9H20
empirical formulas for P4O10
empirical formulas for B2H6
Answer:
CN
CH
C9H20
P205
BH3
Explanation:
The equilibrium constant, Kc, for the following reaction is 83.3 at 500 K. PCl3(g) Cl2(g) PCl5(g) Calculate the equilibrium concentrations of reactant and products when 0.453 moles of PCl3 and 0.453 moles of Cl2 are introduced into a 1.00 L vessel at 500 K.
Answer:
[tex][PCl_3]=[Cl_2]=0.068M[/tex]
[tex][PCl_5]=0.385M[/tex]
Explanation:
Hello!
In this case, since the equilibrium expression for the considered equation is:
[tex]Kc=\frac{[PCl_5]}{[Cl_2][PCl_3]}[/tex]
Which can be written in terms of the reaction extent and the ICE chart and the initial concentrations of 0.453 M as shown below:
[tex]83.3=\frac{x}{(0.453M-x)(0.453M-x)}[/tex]
We can solve for x as follows:
[tex]x=0.385M[/tex]
In such a way, we obtain the following concentrations at equilibrium:
[tex][PCl_3]=[Cl_2]=0.453M-0.385M=0.068M[/tex]
[tex][PCl_5]=0.385M[/tex]
Best regards!
How many grams is 6.11 moles of MgCO3?
Answer:
the answer is 262.216229
Explanation:
:)
Answer:
84.3139 grams.
Explanation:
Which of the following is formed when an acid reacts with a base? (1 point)
Alkaline
Hydrogen ion
Hydroxide ion
Salt
Answer:
Probably Alkaline
Explanation:
Not sure at all.
A catalyst will
a) Increase the reaction rate
b) Move the equilibrium to the right
c) Be consumed by the reaction
d) Increase the activation energy
Answer:
increase the chemical rate
A student has synthesized a new compound (compound A, a nonelectrolyte). She uses osmotic pressure to determine the molar mass of compound A. She dissolves 0.50 g of compound A in water and prepares 15 mL of solution. At 25 C the osmotic pressure is 7.38 atm. Calculate the molar mass (g/mole) of compound A. Do not include a unit with your answer.
Answer:
110g/mol is the molar mass of compound A
Explanation:
The osmotic pressure of a solution could be obtained using the equation:
π = i*M*R*T -Solving molarity we can find the molar mass of the solute A-
Where π is osmotic pressure (7.38atm)
i is Van't Hoff's factor (1 for nonelectrolytes)
M is molarity (Our incognite)
R is gas constant (0.082atmL/molK)
T is absolute temperature (25°C + 273.15 = 298.15K)
Computing the values:
7.378atm = 1*M*0.082atmL/molK*298.15K
0.3018 mol/L is the concentration of the solution.
The volume of the solution is 15mL = 0.015L. Moles of the solute are:
0.3018 mol/L * 0.015L = 4.527x10⁻³ moles
Molar mass is the ratio between mass of the compound (0.50g) and the moles (4.527x10⁻³ moles). That is:
0.50g / 4.527x10⁻³ moles =
110g/mol is the molar mass of compound ARead the list of common household substances.
Yogurt, soaps, window cleaner, vinegar
Which of these substances are likely to have a slippery feel? (1 point)
Yogurt, soaps
Yogurt, vinegar
Soaps, window cleaner
Window cleaner, vinegar
Answer:
A
Explanation:
A student holds their pen 20 centimeters above the desk. If the pen has a mass of 3
grams, how much potential energy does the pen have? (gravity is 9.8 m/s2)
SHOW YOUR WORK.
The potential energy : PE = 5.88 x 10⁻³ J
Further explanationGiven
height = h = 20 cm = 0.2 m
mass = 3 grams = 3 x 10⁻³ kg
Required
The potential energy
Solution
The energy produced from its position is called potential energy (PE)
which can be formulated as:
PE = m. g. h
Input the value :
PE = 3 x 10⁻³ x 9.8 x 0.2
PE = 5.88 x 10⁻³ J
During life body pH is ___ shortly after death the pH becomes ___ after time the pH becomes ___. (A) Acidic, neutral, basic (B) Neutral, acidic, basic (C) Neutral, basic, acidic (D) Acidic, acidic, basic
Calculate the molarity of a solution containing 0.875moles of glucose in 1.5kg of water.
molarity = moles of solute/liters of solution
We know the moles of solute: 0.875 moles of glucose. We can easily determine the liters of solution by using the mass of water given (1.5 kg) and the density of water (approximately 1 kg/L): they're, for all intents and purposes, equal (the approximation isn't large enough to be appreciable here, nor would the volume of the solution appreciably change since the solute is a solid that will dissolve into the solvent). So, we have 1.5 L of solution.
Now, we plug in what we have:
molarity = 0.875 moles of glucose/1.5 L of solution = 0.58 M glucose
The answer is provided to two significant figures since we're given the mass of water to two significant figures.
What type of reaction is _CaCO3 and H2
Decomposition: A substance breaks down to smaller species.
Since carboxylic acids can form hydrogen bonds to create dimers, they have higher boiling points than alcohols and other carbonyl compounds.
a. True
b. False
Answer:
True
Explanation:
The arrangement of three groups COOH, CO, OH in the order of reducing boiling point is as follow -
COOH > OH > CO
COOH gets strongly polarised due to the presence of electron withdrawing carboxy group and hence have strong H+ bonds as compared to that of alcohol.
Hence the given statement is true.
how likely is it that a brother or sister would be just like you.
Answer:
Theoretically you could be totally unrelated to your sister or share the exact same DNA as your brother. But because we are talking about so much DNA and so many different possible combinations, the percentage usually comes out to about 50%. Think about it like flipping a coin.
Explanation:
Explanation:
Theoretically you could be totally unrelated to your sister or share the exact same DNA as your brother. But because we are talking about so much DNA and so many different possible combinations, the percentage usually comes out to about 50%.
In 7 seconds, how far will a ball roll at a speed of 4 meters/second?
Answer:
28 meters
Explanation:
1. Two body systems Which of the following is NOT a part of the integumentary system of the body?
A. hair
B. bones
C. skin
D. finger and toe nailswork together to help remove waste products from blood.
2. What are these two systems?
A. circulatory and excretory
B. skeletal and digestive
C. circulatory and integumentary
D. muscular and excretory
3. One of the functions of the endocrine system in the body is to -
A. circulate blood to all parts of the body
B. collect waste products and remove them from the body
C. provide a strong framework for the body
D. produce enzymes to help digest food
6. When a person’s body needs food, the brain helps maintain homeostasis by sending signals that make the person
A.feel hungry.
B. perspire.
C. put on a sweater.
D. feel tired
7. The largest human body organ which regulates temperature and serves as a barrier against harmful microorganisms belongs to the -
A. circulatory system
B. nervous system
C. digestive system
D. integumentary system
8. Which of the following is NOT a part of the respiratory system?
A. diaphragm
B. esophagus
C. lungs
D. trachea
9. What would happen to your body if you had little or no bone marrow?
A. Your other systems would make up for it
B. You would not have enough red blood cells
C. Nothing would happen to you.
D. You would not have enough cartilage.
What are the particles demonstrating in this image?
O electromagnetic field
O magnetic field
O electromagnetic motor
Oelectric field
Answer:
electromagnetic field