Explanation:
Structural Formulas v. Empirical Formulas
An empirical formula (like a molecular formula) lacks any structural information about the positioning or bonding of atoms in a molecule. It can therefore describe a number of different structures, or isomers, with varying physical properties. For butane and isobutane, the empirical formula for both molecules is C2H5, and they share the same molecular formula, C4H10. However, one structural representation for butane is CH3CH2CH2CH3, while isobutane can be described using the structural formula (CH3)3CH.
Indicate whether each statement is true or false.
a. When a solution is made, the enthalpy of mixing is always a positive number.
b. An increase in entropy favors mixing.
c. A solute will dissolve in a solvent if solute-solute interactions are stronger than solute-solvent interactions.
Answer: a. False.
b. True
c. False
Explanation:
a. When a solution is made, the enthalpy of mixing is always a positive number.
This is false. It should be noted that the nature of reaction determine the enthalpy which can either be positive or can be negative.
b. An increase in entropy favors mixing.
This is true because when molecules get randomly distributed, they mix with one another. Therefore, an increase in entropy favors mixing.
c. A solute will dissolve in a solvent if solute-solute interactions are stronger than solute-solvent interactions.
This is false. This is because the solute-solute interactions have to be weaker and not stronger.
a. When a solution is made, the enthalpy of mixing is always a positive number. FALSE
b. An increase in entropy favors mixing. TRUE
c. A solute will dissolve in a solvent if solute-solute interactions are stronger than solute-solvent interactions. FALSE
EntropyEntropy is the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work
EntalphyEnthalpy is the sum of the system's internal energy and the product of its pressure and volume.
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What is the cathode ray? How was the Nature of cathode rays determined?
Answer:
Cathode rays are streams of electrons observed in discharge tubes. In 1897, British physicist J. J. Thomson showed that cathode rays were composed of a previously unknown negatively charged particle, which was later named the electron. Cathode-ray tubes (CRTs) use a focused beam of electrons deflected by electric or magnetic fields to render an image on a screen.
Density of water is affected by (select all that apply)
A) Animals that life in the area
B) Salinity (salt concentration)
C) Temperature of water
D) Amount of plants in an area
E) How close the water is to land
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:
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
The octane number of gasoline is a measure of octane activity. The octane activity is determined by comparing the engine performance using gasoline and known mixtures of isooctane and n-heptane.
a. True
b. False
Answer:
A. True
Explanation:
The octane number is determined by comparing the characteristics of gasoline to isooctane (2,2,4-trimethylpentane) and heptane. The correct option is option A.
Basically, the higher the octane number, the greater the resistance of the gasoline to knocking.
Which components of the apparatus affect in motion? If you answer this and it has non to do with the question imma report u!!!!
Answer:
Explanation:
An internal force acts between elements of the system. Only external forces affect the motion of a system, according to Newton's first law. Newton's second law states that a net force on an object is responsible for its ... Prior to manned space flights, rocket sleds were used to test aircraft, missile equipment, and physiological
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Click an item in the list or group of pictures at the bottom of the problem and, holding the button down, drag it into the
correct position in the answer box. Release your mouse button when the item is place. If you change your mind, drag
the item to the trashcan. Click the trashcan to clear all your answers.
Make a Punnett Square for two smooth seed hybrid pea plants (Ss)
Click once to select an item at the bottom of the problem.
Click again to drop the item in its correct place.
S
SS SS SS S
One mole of a metallic oxide reacts with one mole of hydrogen to produce two moles of the pure metal
and one mole of water. 5.00 g of the metallic oxide produces 2.32 g of the metal. What is the metallic
oxide? (Use molar masses)
Answer:
Lithium oxide, Li₂O.
Explanation:
Hello!
In this case, according to the given amounts, it is possible to write down the chemical reaction as shown below:
[tex]M_2O+H_2\rightarrow 2M+H_2O[/tex]
Which means that the metallic oxide has the following formula: M₂O. Next, we can set up the following proportional factors according to the chemical reaction:
Thus, we perform the operations in order to obtain:
[tex]\frac{10X}{(2X+16)}=2.32[/tex]
So we solve for x as shown below:
[tex]10X=2.32(2X+16)\\\\10X=4.64X+37.12\\\\X=\frac{37.12}{10-4.64}\\\\X= 6.93g/mol[/tex]
Whose molar mass corresponds to lithium, and therefore, the metallic oxide is lithium oxide, Li₂O.
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What is the M, of C3H,COONa? A: Na = 23; C = 12, 0 = 16:
110
87
98
103
Answer: Molecular mass of [tex]CH_3COONa[/tex] is 82 g
Explanation:
Molecular mass (M) is defined as the mass in grams of 1 mole of a substance.
S.I Unit of Molar mass is gram per mole and it is represented as g/mol.
Atomic Mass of Carbon (C) = 12 g
Atomic Mass of hydrogen (H) = 1 g
Atomic Mass of oxygen (O) = 16 g
Atomic Mass of sodium (Na) = 23 g
Molecular mass of [tex]CH_3COONa[/tex] = 12(1)+1(3)+12(1)+16(2)+23(1) = 82 g
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
How long will it take for the concentration of A to decrease from 0.850 M to 0.205 for the reaction A → Products? (k = 0.0882 M⁻¹s⁻¹)
Answer:
16.1 s
Explanation:
The reaction, A → Products, follows first order kinetics.
So,
ln[A] = ln[A]o - kt
Where;
[A] = concentration at time= t
[A]o = initial concentration
k= rate constant
t = time taken
ln(0.205) = ln(0.850) - 0.0882t
ln(0.205) - ln(0.850) = - 0.0882t
-1.5847 - (-0.1625) = - 0.0882t
-1.5847 + 0.1625 = - 0.0882t
-1.4222 = - 0.0882t
t = -1.4222/- 0.0882
t = 16.1 s
Based on first order kinetics, the time taken for the concentration of A to decrease from 0.850 M to 0.205 M is 16.1 seconds.
What is order of a reaction?The order of a reaction refers to the relationship between the rate of a reaction and the the concentration of each reactant.
For a first-order reaction, the rate is dependent on the concentration of a single species.
The reaction, A → Products is a first order reaction.
Therefore, using the first order kinetics equation
ln[A] = ln[A]° - kt
Where;
[A] = concentration at time= t[A]° = initial concentrationk= rate constantt = time takenSubstituting the values:
ln(0.205) = ln(0.850) - 0.0882t
ln(0.205) - ln(0.850) = - 0.0882t
-1.5847 - (-0.1625) = - 0.0882t
-1.5847 + 0.1625 = - 0.0882t
-1.4222 = - 0.0882t
t = -1.4222/- 0.0882
t = 16.1 s
Therefore, the time taken for the concentration of A to decrease from 0.850 M to 0.205 M is 16.1 seconds.
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Compute the value of the molar heat capacity at constant volume, CVCV, for CO2CO2 on the assumption that there is no vibrational energy. (Note: CO2CO2 is linear; SO2SO2 and H2SH2S are not. Recall that a linear polyatomic molecule has two rotational degrees of freedom, and a nonlinear molecule has three.)
Answer:
Explanation:
Molar heat capacity at constant volume Cv of a gas = n x .5 R where n is degree of freedom of the gas molecules
CO₂ is a linear molecule , so number of degree of freedom = 3 + 2 = 5
3 is translational and 2 is rotational degree of freedom . There is no vibrational degree of freedom given .
So Cv = 5 / 2 R
= 2.5 R .
The act of changing something but not being able to change it back
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.
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.
What is the Chemical formula for Hexacarbon octaphosphide?
Answer:C6P8
Explanation:
What describes how a liquid flows and diffuses?
A: Fluidity
B: Viscosity
C: Surface tension
D: Condensation
The answer is option is a fluidity
Answer:
A. According to the kinetic-molecular theory of liquids, the particles are not bound together in fixed positions; instead they move about constantly giving them their fluidity
Nuclear energy could come from
A
kicking a soccer ball.
B
heat inside the Earth.
C
splitting atoms apart.
D
solar panels.
Answer:
C Splitting atoms apart
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
A diver planning to dive to a depth of 100 ft can choose to breathe air that is a mixture of oxygen, nitrogen, and helium. If the total pressure of the air in the tank is 3040 mm Hg , and the partial pressures of O2 and He are 304 mm Hg and 1520 mm Hg , respectively, what is the partial pressure of N2
Answer:
1216 mmHg = Partial pressure N₂
Explanation:
In a mixture of n gases, the partial pressure of each compound follows the equation:
Total pressure = Partial pressure n₁ + Partial pressure n₂ + Partial pressure n₃ + Partial pressure n₄ + Partial pressure n₅ + ... + Partial pressure nₙ
In a mixture of O₂, He and N₂, the total pressure = 3040mmHg is defined as:
3040 mmHg = Partial pressure O₂ + Partial pressure He + Partial pressure N₂
Replacing:
3040 mmHg = 304 mmHg + 1520 mmHg + Partial pressure N₂
3040 mmHg = 1824 mmHg + Partial pressure N₂
1216 mmHg = Partial pressure N₂
b) All atoms contain
charged electrons.
Answer:
b) All atoms contain
charged electrons.
Explanation:
Choose the aqueous solution below with the highest freezing point. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.
(i) 0.200 m HOCH2CH2OH
(ii) 0.200 m Ba(NO3)2
(iii) 0.200 m K3PO3
(iv) 0.200 m Ca(CIO4)2
(v) These all have the same freezing point.
Answer:
0.200 m K3PO3
Explanation:
Let us remember that the freezing point depression is obtained from the formula;
ΔTf = Kf m i
Where;
Kf = freezing point constant
m = molality
i = Van't Hoff factor
The Van't Hoff factor has to do with the number of particles in solution. Let us consider the Van't Hoff factor for each specie.
0.200 m HOCH2CH2OH - 1
0.200 m Ba(NO3)2 - 3
0.200 m K3PO3 - 4
0.200 m Ca(CIO4)2 - 3
Hence, 0.200 m K3PO3 has the greatest van't Hoff factor and consequently the greatest freezing point depression.
Why do clumps of particles have slower reaction rates than particles that are separated?
Explanation:
Cause the clumps are so compacted together that it is harder to brake apart but the one that are separated are easy cause they do not have all the pressure on them and when they go to add reaction it is faster
Rank the effective nuclear charge Z* experienced by a valence electron in each of these atoms:
atom Z* experienced by a valence electron.
An atom of carbon.
An atom of fluorine.
An atom of beryllium.
An atom of boron.
Answer:
The atoms are ranked in decreasing order as follows:
Fluorine ---4
Carbon ----3
Boron ------2
Beryllium --1
Explanation:
Effective nuclear charge (Zeff) is defined as the difference between the actual nuclear charge (the atomic number, Z) and the shielding constant (S).
It is calculated by finding the atomic number and electronic configuration, attributing a shielding value to each electron, adding all the shielding values and using the formula:
Z eff = Z - S
Effective nuclear charges:
An atom of carbon: 3.25
An atom of fluorine: 5.20
An atom of beryllium: 1.95
An atom of boron: 2.60
C3H8 (g)+ 502 (g) 3CO2 (g) + 4 H2O (g) + 531 kcal
Answer:
Exotérmica.
Explanation:
¡Hola!
En este caso, dado que la mayoría de reacciones de combustión son exotérmicas, al generar calor en los productos, es posible inferir que esta reacción, referida a la combustion de metano es exotérmica debido a lo anteriormente mencionado, ya que el término de energía de reacción, 531 kcal, está al lado de los productos, lo que quiere decir que es energía generada.
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If 50 ml of 0.235 M NaCl solution is diluted to 200.0 ml what is the concentration of the diluted solution
This is a straightforward dilution calculation that can be done using the equation
[tex]M_1V_1=M_2V_2[/tex]
where M₁ and M₂ are the initial and final (or undiluted and diluted) molar concentrations of the solution, respectively, and V₁ and V₂ are the initial and final (or undiluted and diluted) volumes of the solution, respectively.
Here, we have the initial concentration (M₁) and the initial (V₁) and final (V₂) volumes, and we want to find the final concentration (M₂), or the concentration of the solution after dilution. So, we can rearrange our equation to solve for M₂:
[tex]M_2=\frac{M_1V_1}{V_2}.[/tex]
Substituting in our values, we get
[tex]\[M_2=\frac{\left ( 50 \text{ mL} \right )\left ( 0.235 \text{ M} \right )}{\left ( 200.0 \text{ mL} \right )}= 0.05875 \text{ M}\].[/tex]
So the concentration of the diluted solution is 0.05875 M. You can round that value if necessary according to the appropriate number of sig figs. Note that we don't have to convert our volumes from mL to L since their conversion factors would cancel out anyway; what's important is the ratio of the volumes, which would be the same whether they're presented in milliliters or liters.
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Using an applied force to move an object in the direction of the force is...
potential energy
the scientific definition of work
none of these
the scientific definition of power
Answer:
the scientific definition of work
Explanation:
In physics, work is defined as the use of force to move an object. For work to be done, the force must be applied in the same direction that the object moves.
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explain why vapour pressure increases with increasing temperature.
When you remove energy from air or land it makes the temperature