Answer:
55
Explanation:
Plants and animals need to protect themselves to survive. Select the statement that best describes the adaptions of animals and plants.
HELPP asap I’ll mark you as brainlister!!!!!!
What volume of 5.00 M KI stock solution is needed to make 250. mL of a 1.50 M solution?
A) 0.0300 mL
B) 33.3 mL
C) 75.0 mL
D) 833 mL
Taking into account the definition of dilution, the correct answer is option C): 75 mL of the stock solution are required to prepare 250 mL of a 1.50 M solution.
Definition of dilutionYou have to know that when it is desired to prepare a less concentrated solution from a more concentrated one, it is called dilution.
Dilution is the process of reducing the concentration of solute in solution, which is accomplished by simply adding more solvent to the solution at the same amount of solute.
In a dilution the amount of solute does not change, but as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.
A dilution is mathematically expressed as:
Ci×Vi = Cf×Vf
where:
Ci: initial concentrationVi: initial volumeCf: final concentrationVf: final volumeVolume of 5.00 M KI stock solution neededIn this case, you know:
Ci= 5 M Vi= ?Cf= 1.5 MVf= 250 mL= 0.250 L (beign 1 L= 1000 mL)Replacing in the definition of dilution:
5 M× Vi= 1.5 M× 0.250 L
Solving:
Vi= (1.5 M× 0.250 L)× 5 M
Vi= 0.075 L= 75 mL
In summary, the correct answer is option C): 75 mL of the stock solution are required to prepare 250 mL of a 1.50 M solution.
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State TWO ways in which stress could impact negatively on student's
performance at College or university.
Two ways that stress could negatively impact a students performance is by causing them to procrastinate. When you're stressed, you tend to keep putting things off because you "just can't deal with it" at the moment. This could cause the student to turn in their assignments late (or not at all) and cause their grades to drop. Additionally, when you're stressed, it's harder to fall asleep, and once you are, you don't sleep as well. Sleep deprivation can greatly affect a student's in class performance by causing them to fall asleep in class, or not pay attention as well.
Hydrogen bonding in water molecules results in all of the following properties except?
Answer:
Transparent Color
Explanation:
Hydrogen bonds here in water provides a lot of benefits which includes cohesion, releasing heat when forming, Also because of the fact that water molecules are polar, they form hydrogen molecules and give water some characteristics which ranges from high boiling point, relative gravity, adhesion ad also cohesion. It is also known that oxygen atom attracts the electrons more strongly than the hydrogen.
A transparent colour falls in no place and do not really have any correlation in oxygen and hydrogen relationship.
The presence of hydrogen bonds in molecules affects the bulk properties of the molecules.
Though the question is incomplete but I will try to help you the much I can. hydrogen bonding is said to occur in molecules where hydrogen is bonded to a highly electronegative atom such as nitrogen, oxygen and fluorine.
The presence of hydrogen bonding in molecules affects its bulk properties such as melting and boiling points, density and surface tension.
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hi how do u determine the mass of NaCl [i'm not talking about the molar mass and also pls don't send links to this question]
What is the state change of a gas to a liquid is called?
Answer:The process in which a gas changes to a liquid is called condensation. Other examples of condensation are shown in Figure below. A gas condenses when it is cooled below its boiling point.
Explanation:
There are 4 phases for h20 solid liquid vapour and gas.
In the vacuum of space there are only 2 phases solid and gaseous, both liquid and vapour cannot exist in the absolute freezing temperature of the vacuum of space and crystalise instantly.
Watch a space shuttle dump water in space and it instantly freezes, and when in direct sunlight instantly turn to its gaseous phase and becomes invisible to the naked eye by the process of sublimation.
When h20 freezes in the shadow of the shuttle to ice crystals they instantly sublimate to the a gaseous state when they come into contact with direct sunlight.
You can see all 4 phases if you place ice cubes [ solid phase ] in a pan on a stove, the Solid beComes liquid [ liquid phase ]and the liquid becomes a gas in the bottom of the pan when the water boils, [ gaseous phase ] the bubbles coming up from the bottom are the instant phase change from liquid to gas, when the gas bubbles break the surface of the water and the gas comes into contact with the cooler air the gas instantly starts to condense to water droplets i.e. the vapour phase
You can see through the bubbles because h20 in its gaseous phase is invisible to the naked eye.
Gaseous h20 is hot dry and invisible
Vaporous h20 is warm wet and visible
Gaseous h20 is known as a condensing gas in physics because it condenses obviously, condensing gases are also known as optically active gases or radiatively active gases.
Hope this helps all the 3 phase numpties who think vapour i.e. water droplets is actually gas, it isnt or it wouldn’t be called vapour it would be called gas.
Liquid water has to reach its boiling point before it will phase change to its gaseous phase.
Vapor has to boil before the water droplets will phase change to a gaseous state, steam is not gas it is condensing gas i.e. vapour at a lower temperature than boiling point.
hope this helps have a nice day
As the randomness of a system increases, the entropy of the system:
A) decreases
B) increases
C) remains the same
Answer:
it most likely increases
6.
Why are estuaries home to diverse marine life not found elsewhere?
is hrimming with
Answer:
Estuaries are bodies of water where rivers meet the sea or a large lake. Rivers spread out and slow when they meet the sea, creating unique conditions that are not found elsewhere. They provide homes for diverse wildlife, including popular fish species.
Is a 3.3% solution dilute or concentrated?
Dilute
Concentrated
Answer:
Dilute
Explanation:
A concentrated solutions is a one which has relatively large amount of dissolved solute in the solution whereas a dilute solution is a one which has relatively lower concentration of dissolved solute.
In the given solution there is only 3.3% of solute. So, we can say that the given solution is a dilute solution. However, these terms are relative.
Which of the following is an example of a micro-habitat?
a
Abuela's vegetable garden on her huge farm
b
Ms. Steinmann's 200 gallon fish tank
c
woods behind the school
d
the algae growing on a seashell where tiny sea animals called plankton live
How are plant cells different from animal cells?
Select the three correct statements.
A. Their cells have cell walls.
B. They can convert the sun's energy into food.
C. They have chloroplasts.
D. They can move around.
E. They cannot make their own food.
pls help this is due today
Answer:
b.
They can convert the sun's energy into food.
Answer:
its letter A
because Plant cells have a cell wall, but animals cells do not.
Perform the following
mathematical operation, and
report the answer to the correct
number of significant figures.
3.47 x 6.7 = [?]
Answer:
[tex]3.4 \times 6.7 = 23.249[/tex]
Answer:
23.25
Explanation:
3.47x6.7= 23.249= 23.25 / 23.
how many Na atomd are shown in the reactants
Answer:
On the reactant side, there are two H atoms and two O atoms
can someone pls help me answer e-j given the instructions above, thank youu
Answer:
e. Not balanced C and O
f. Balanced
g. Balanced
h. Unbalanced Al and O
i. Balanced
j. Balanced
Second part
a. 2
b. 2 and 2
c. For O is 5 while H20 is 4
Explanation:
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How could a scientist use a sedimentary rock to provide evidence that the right k cycle is a valid scientific model
Answer:
By closely observing the sedimentary rock and the presence of organic materials and mineral grains in sedimentary rocks
Explanation:
The rock cycle explains how the three types of rock are formed over time from each other.
To use a sedimentary rock to prove that the rock cycle is a valid scientific model is by, closely observing the sedimentary rock. when the sedimentary rock is closed observed the principle of superposition will be seen ( i.e. younger segments deposited on top ), the presence of organic materials and mineral grains that can be found in Igneous or Metamorphic rocks can also be seen and this shows that Sedimentary rocks pass through the rock cycle. hence this proves that the rock cycle is a valid scientific model overtime
What term is used to define when a substance reacts quickly with oxygen to produce light and heat?
A. rusting
B. sublimation
C. precipitation
D. burning
Answer:
I think it's a
Explanation:
not sure hssjkskaakakskksskksqoqkakskzksjsj
Answer: The answer is, D) Burning.
Explanation: Some moderator removed my last answer because someone reported it.
Which of the following arrangements of electrons represent Potassium? *
a. 2,6,3,8
b. 2,7,8,2
c. 2,8,8,1
d. 2,9,7,1
When filling a weather balloon with gas you have to consider that the gas will expand greatly as it rises and the pressure decreases. Let's say you put about 10.0 moles of He gas into a balloon that can inflate to hold 5000.0L. Currently, the balloon is not full because of the high pressure on the ground. What is the pressure when the balloon rises to a point where the temperature is -10.0°C and the balloon has completely filled with the gas.
Answer:
0.0432 atm
Explanation:
Step 1: Given data for when the balloon is full
Moles of Helium (n): 10.0 molVolume of the balloon (V): 5000.0 LTemperature (T): -10.0 °CIdeal gas constant (R): 0.0821 atm.L/mol.KStep 2: Convert "T" to Kelvin
We will use the following expression.
K = °C + 273.15
K = -10.0°C + 273.15 = 263.2 K
Step 3: Calculate the pressure of He in the balloon
We will use the ideal gas equation.
P × V = n × R × T
P = n × R × T/V
P = 10.0 mol × (0.0821 atm.L/mol.K) × 263.2 K/5000.0 L = 0.0432 atm
The covalent bonds in an oxygen, molecule, O2, are polar.
O True
O False
Answer:
true
Explanation:
Which body system includes the heart?
As part of each science lab, Mr. Arico requires his student to wash their glassware, so it is clean for the next class. He has found that the glassware is cleaner when students wash it in front of their classmates. This is best explained by
social facilitation
deindividuation
social loafing
the mere exposure effect
groupthink
Answer:
social facilitation
Explanation:
The glassware is cleaner when students wash it in front of their classmates is best explained by social facilitation. Hence, option A is correct.
What is social facilitation?Social facilitation is a psychological concept relating to the tendency for the presence of others to improve a person's performance on a task.
Social Loafing: When a person does not show much effort to achieve a goal when they work in a group than when they work alone.
Social Facilitation: When a person can do better at simple tasks when in the presence of other people.
So the first one is basically saying a person is less working when n a group of other and the second one is saying that this person can work on simple things when people are around.
Hence, the glassware is cleaner when students wash it in front of their classmates is best explained by social facilitation.
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In a solution, litmus is blue. The pH of the solution could be
1 10 2 2 3 3 4 4
Answer:
absotutately right
Explanation:
What is the pH color scale?
The pH scale runs from 0 to 14, with each number assigned a different color. At the bottom of the scale sits red, which represents the most acidic, and a dark blue at its opposite end represents 14 and alkalinity. In the middle zone, the pH scale becomes neutral
The pH of the solution could be 10. The basic solution has a pH value of more than 7.
What is pH?pH is a measure of acidity and basicity of aqueous solution.The range of pH goes from 0 - 14, with 7 being neutral.pH of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base.pH is the measure of the relative amount of free hydrogen and hydroxyl ions in aqueous or other solutions.Litmus paper helps us qualitatively determine a substance as an acid or base. For any substance to be a base, blue litmus must remain blue.
The pH scale ranges from 0 to 14 and anything below 7.0 is acidic and anything above 7.0 is alkaline or basic.
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The equation A+ BX à AX + B is the general equation for a
Answer: d
Explanation:
took the test
A mixture of gases in a container has a pressure of 1275.5 mm Hg. If the pressure of CO2 gas is 335.3 mm Hg and the pressure of N2 gas is 418.0 mm Hg, what is the pressure of O2 gas.
whats the most effective way to study when your teachers dont tell you about a test until the day before the test.? help! currently struggling
Explanation:
You should read the most important questions properly and you should look your syllabus of test.
You should read old questions of test
that were already asked.
The inner wall of the trachea is lined with ciliated mucous membrane loaded full with what?
Answer:
the trachea is full of cilia
How many moles of a gas would occupy 11.4 L at 273K and 2.00 atm?
Answer:
1.02mol
Explanation:
Using the general gas equation below;
PV = nRT
Where;
P = pressure (atm)
V = volume (L)
n = number of moles (mol)
R = gas law constant (0.0821 Latm/molK)
T = temperature (K)
According to the information provided in this question,
P = 2.0 atm
V = 11.4L
T = 273K
n = ?
Using PV = nRT
n = PV/RT
n = 2 × 11.4/ 0.0821 × 273
n = 22.8/22.41
n = 1.017
n = 1.02mol
The sun is located at 1 astronomical unit from Earth. How far is the next closest star to Earth?
A. It is about twice as far from earth as the sun.
B. It is about 100 times as far from earth as the sun.
C. It is about the same distance from Earth as the
sun.
D. It is many thousands of times as far from the Earth as the sun.
answer:
d
Explanation:
sun 109 million miles
2 star trillion of miles
Calculate the standard potential, ∘, for this reaction from its equilibrium constant at 298 K. X(s)+Y3+(aq)↽−−⇀X3+(aq)+Y(s)=6.90×10−8 X ( s ) + Y 3 + ( aq ) ↽ − − ⇀ X 3 + ( aq ) + Y ( s ) K = 6.90 × 10 − 8
Answer: The standard potential is -0.141 V
Explanation:
To calculate the Gibbs free energy for given value of equilibrium constant we use the relation:
[tex]\Delta G=-RTlnK[/tex]
where,
= standard Gibbs free energy = ?
R = Gas constant = 8.314 J/Kmol
T = temperature = 298 K
K = equilibrium constant =
Putting values in above equation, we get:
[tex]\Delta G=40853J[/tex]
Also [tex]\Delta G=-nFE^0[/tex]
where n = no of electrons gained or lost = 3
F = Faradays constant = 96500 C
[tex]E^0[/tex] = standard potential = ?
[tex]40853=3\times 96500\times E^0[/tex]
[tex]E^0=-0.141V[/tex]
Thus the standard potential is -0.141 V