Answer:
0.0326 moles
explanation
Answer:
0.234 mol
Explanation:
m(CaCO3) = 23.4g
n(CaCO3) = ?
M(CaCO3) = 100.09 g/mol
n = m/M
n(CaCO3) = 23.4 / 100.09
= 0.234 mol (3 s.f.)
1. A green rat snake that lives in the grass and a brown rat snake that lives
in the desert is a form of
A. Human genetic modification
B. Selective breeding
C. Natural selection
D. Artificial breeding
Answer:
It is an example of natural selection (option c)
Natural selection is demonstrated by a green rat snake living within that grass as well as a brown rat snake living throughout the desert.
Natural selection:The process throughout which communities of sentient creatures adapt but instead transform is known as natural selection. Persons within a demographic are inherently varied, which means they are all unique under certain manner.
This variance indicates that certain people have qualities that are more adapted to their surroundings over others.
Thus "Option C" is correct.
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generators need sources of energy to produce electricity. which form of energy is a noble where source of energy
A. hydro (water) energy
B. geothermal energy
C. fossil fuel
D. wind energy
Answer:
B
Explanation:
What happens to the average kinetic energy of gas particles as temperature increases?
Answer:
it dies
Explanation:cause its too cold
Acetic acid (ch3cooh) and trifluoroacetic acid (cf3cooh) are shown by these particulate models. the ka for trifluoroacetic acid is 104 times greater than acetic acid. use the models to account for the differences in magnitude for the ka constant. the green atoms are fluorine, the red atoms are oxygen, the black atoms are carbon, and the white atoms are hydrogen.
Answer:
See explanation
Explanation:
If we look at the models, we will see that the three fluorine atoms in CF3COOH are attached to the carbon that is next to the -COOH group.
As a result of the electron withdrawing effect of the three fluorine atoms, CF3COOH is much more acidic (104 times more acidic) than CH3COOH. This is reflected in the value of the Ka for each acid.
This electron withdrawing effect of the three fluorine atoms also stabilizes CF3COO- much more than CH3COO-.
The orbits of the planets in our solar system are
not
a Elliptical, circular
b Circular, elliptical
C Circular, oval
d None of the above
Answer:
A
Explanation:
I don't know how to say how I got it.
Answer:
d
Explanation:
the orbits of the planets in our circular elliptical and circular
Sea water contains 2% salt (NaCl) by weight. Given that water has a
density of 1g/mL. Determine the concentration of salt in:
(a) mg/L , (b) ppm.
Answer:
a) Concentration of salt in mg/L = 2g/100mL
b) concentration in ppm = 20000 ppm
Explanation:
Percentage composition of salt by weight in water = 2%
Density of water = 1 g/mL
100 mL of water will has a mass of 100 g
Mass of salt in 100 g of water = 2% ×100 g = 2 g
Therefore, 2 g of salt is dissolved in 100 mL of solution
Concentration of salt in 100 mL of solution = 2g/100mL
a) Concentration in mg/L
Mass of salt = 2 g = 2000 mg
Volume of solution = 100 mL = 0.1 L
Concentration in mg/L = 2000 mg/0.1 L
Concentration in mg/L = 20000 mg/L
b) Concentration in ppm
1 ppm = 1mg/L
Therefore, concentration in ppm = 20000 ppm
Which of the following best defines base isolation?(1 point)
Base isolation is a technique used by engineers to help prevent damage to buildings by volcanoes. The main structure of the building is separate from the base, which allows lava to pass under the building without causing much damage.
Base isolation is a technique used to prevent large-scale damage from volcanoes. New communities being built are set as far back as possible from the base of a volcano.
Base isolation is a technique used to prevent damage to buildings during tsunamis. The main structure of the building is separate from the base, which allows water to pass beneath buildings without causing much damage.
Base isolation is a technique used by engineers to help prevent damage to buildings by earthquakes. The main structure of the building is separate from the base and sits on a bed of springs.
Base isolation is a technique used by engineers to help prevent damage to buildings by earthquakes. The main structure of the building is separate from the base and sits on a bed of springs.
What is base isolation?Base isolation is a technique developed to prevent or minimise damage to buildings during an earthquake.
A base isolation system is a method of seismic protection where the structure (superstructure) is separated from the base (foundation or substructure). By separating the structure from its base the amount of energy that is transferred to the superstructure during an earthquake is reduced significantly.
Hence, option D is correct.
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Sodium chloride is a ____ substance because the atoms within are arranged in repeating patterns.
work bank
- crystalline
- hydrogen bonds
- hydrophilic
- hydrophobic
- polar molecule
- solvent
true or false. a short circuit cannot cause a fire
Answer:
false
Explanation:
Answer:
FalseExplanation:
A short circuit can cause a spark or fire.
A gas tank contains 2.5 moles of oxygen, 7.0 moles of nitrogen and 0.5 mole of water vapor. The total pressure of the mixture is 852 torr. Calculate the partial pressure of each gas. Show work.
Answer:
The partial pressure of each gas is:
Oxygen= 213 torrNitrogen= 596.4 torrWater Vapor= 42.6 torrExplanation:
The pressure exerted by a particular gas in a mixture is known as its partial pressure. So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone:
PT = PA + PB
This relationship is due to the assumption that there are no attractive forces between the gases.
Dalton's partial pressure law can also be expressed in terms of the mole fraction of the gas in the mixture. The mole fraction is a dimensionless quantity that expresses the ratio of the number of moles of a component to the number of moles of all the components present.
The mole fraction of a gas in a gas mixture is given by:
XA = nA / nT
This fraction will always be less than 1.
So in a mixture of two or more gases, the partial pressure of gas A can be expressed as:
PA = XA * PT
In this case, you know:
number of moles of oxygen= 2.5 molesnumber of moles of nitrogen= 7.0 molesnumber of moles of water vapor= 0.5 molesSo, the number of total moles nT is calculated as:
nT= number of moles of oxygen + number of moles of nitrogen +number of moles of water vapor
Then:
nT= 2.5 moles + 7.0 moles + 0.5 moles
nT= 10
So, the mole fraction of the gas in the mixture is:
mole fraction of oxygen = [tex]\frac{2.5 moles}{10 moles}[/tex] = 0.25mole fraction of nitrogen = [tex]\frac{7 moles}{10 moles}[/tex] = 0.7mole fraction of water vapor = [tex]\frac{0.5 moles}{10 moles}[/tex] = 0.05Being the total presurre (PT) equal to 852 torr, then:
Poxygen= 0.25*852 torr= 213 torrPnitrogen= 0.7*852 torr= 596.4 torrPwater vapor= 0.05*852 torr= 42.6 torrThe partial pressure of each gas is:
Oxygen= 213 torrNitrogen= 596.4 torrWater Vapor= 42.6 torrIn an isolated system, mass can neither be
created or destroyed.
ube
FALSE
TRUE
Answer:
True
Explanation:
The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
Hope it helps
PLSSSSSSSS ANSWERRRRR
why is it necessary to specify temperature when giving Ka value
Answer:
Because the equilibrium constant is only at constant at temperature. Changing the temperature changes the Ka.
Describe the effect of resonance on the amount of rotation that can occur in the main chain of your tripeptide (phenylalanine, alanine, and tyrosine), which affects protein folding.
Answer:
use research.
Explanation:
Gases Test
Chemistry
Answer:
6.64 l is the answer.......
Iron + --> iron sulphate + copper What is missing ? Iron sulphate Copper sulphate Copper oxideIron oxide
Answer:
Copper Sulphate is missing
PLEASE WILL MARK BRAINLYIST
Answer:
3 i am pretty sure make me brainy i gust
Explanation:
What would be the volume, in liters, of 85.5 grams of carbon monoxide at STP?
Matching
Enter the letter of the box whose contents best match the description.
8
8
8
a
b
с
e
f
v a mixture of molecules
atoms of a pure elementa metal
molecules of an element
va solid compound
a mixture of elements
a. box a
b. box e
c. box b
d. box f
e. box d
f. box c
QUESTION 10
Answer:
a mixture of molecules - Box f
atoms of a pure elementa metal - Box D
a solid compound - Box C
a mixture of elements - Box A
Explanation:
Box a has mixture of elements which forms a solid like shape but there are different elements present in the box. The box f has mixture of molecules in which many atoms are combined together. Box c has solid compound with single element.
will mark BRAINLYIST
please help
1.00mol is the correct answer
What is climate and what are the two main factors that affect climate?
Need answers within 5 minutes!
Answer:
climate:the weather conditions prevailing in an area in general or over a long period.
2 main factors: temperature and precipitation
Explanation:
3NaHCO, +CHO - CH. Na 0, +300, +3H, 0.
Name one reactant and one product
Но Water Lewis steucture
what are asking commet it and I might be able to help
Is changing the color of the coin from copper to silver a physical or chemical change?
Answer:
physical
Explanation:
The zinc (which was already silver) coated the penny. The NaOH dissolved the zinc. (that was what made the water murky) And small pieces of zinc adhered to the penny (coated) It was a physical change because no NEW color was created.
someone help ,, I'll give brainliest lolll .
Answer:
the correct answer is c, how easily something catches flames
2.00 L of a gas is collected at 25.0°C and 745.0 mmHg. What is the volume at 760.0 mmHg
and 273K?*
1.7960L
Explanation:
the mass of the gas is constant in both instances
pv/T=constant(according to pv=nRT)
745mmHg*2L/298K=760mmHg*v/273K
v=1.7960L
what is the name of the part of a cell that allows molecules in in, such as glucose and oxygen?
Answer:
A plasma membrane is permeable to specific molecules that a cell needs. Transport proteins in the cell membrane allow for selective passage of specific molecules from the external environment. Each transport protein is specific to a certian molecule (indicated by matching colors).
3 – Simple Diffusion Across the Cell (Plasma) Membrane: The structure of the lipid bilayer allows small, uncharged substances such as oxygen and carbon dioxide, and hydrophobic molecules such as lipids, to pass through the cell membrane, down their concentration gradient, by simple diffusion.
Or Cell Membrane
Explanation:
Hope This HElp??
Please MArk Me Brainly!!
How would you prepare a 1 L solution of 3 M MgO?
Answer: 175.35g
Explanation: A 3 M solution has 3 moles of solute per litre.
The mass of one mole of NaCl equals the MW of NaCl MW = 35.45 + 23 =58.45 g/mol
The mass of 3 moles is 58.45 g/mol ×3 mol=175.35 g NaCl or 200 g rounded to one sigfig.
PLEASE HELP!! Answer whatever ones you can please and thank you!!!!
1. A gas with a volume of 4.0 L at a pressure of 2.03 atm is allowed to expand to a volume of 12.0 L. What is the pressure in atm in the container if the temperature remains constant. Please show work (including the equation you used).
2.The volume of a gas is 200 mL at 350.0 kPa pressure. What will the volume be when the pressure is reduced to 120.0 kPa, assuming the temperature remains constant. Please show all work for full credit. Please show work (including the equation you used).
3.What is the original pressure of a bike tire if the current pressure is 150 atm and the volume changed from 1000 mL to 700 mL. Please show work (including the equation you used).
These problems can be solved using the gas laws. The combined gas law states that PV/T = k, where P is the pressure, V is the volume, T is the temperature (in Kelvin), and k is a constant. From this relationship, you can figure out the change in pressure, volume, or temperature of a gas provided that one of those three parameters remains unchanged. This will be shown in the problems given.
1. Here, the pressure and volume of a gas change while the temperature remains constant. Since PV/T = k, if T is also constant, then the relationship becomes PV = k. In other words, the pressure and volume of a gas at a constant temperature are inversely proportional to each other. This can be expressed mathematically as [tex]P_1V_1=P_2V_2[/tex] (also called Boyle's Law), where P₁ and V₁ denote the initial pressure and volume, and P₂ and V₂ denote the final (or changed) pressure and volume, respectively.
We are given a gas with an initial pressure, P₁, of 2.03 atm and an initial volume, V₁, of 4.0 L. We are also told that the gas expands to a final volume, V₂, of 12.0 L. So, we are looking for P₂: The pressure of the gas when the volume has expanded from 4.0 to 12.0 L. From Boyle's Law,
[tex]P_2=\frac{P_1V_1}{V_2}[/tex].
Thus,
[tex]\[P_2=\frac{\left ( 2.03 \text{ atm} \right )\left ( 4.0 \text{ L} \right )}{\left ( 12.0 \text{ L} \right )}\] = 0.67 atm.[/tex]
Since the pressure and volume of a gas are inversely proportional, as one increases, the other decreases, and vice versa.
2. This is another Boyle's Law problem, but this time, we have to figure out what the final volume will be when the pressure of a gas is changed. Since the pressure is reduced, we can deduce that the volume must increase (notice the parallel with the previous question). We again turn to Boyle's Law, and this time we solve for V₂:
[tex]V_2=\frac{P_1V_1}{P_2}[/tex]
from which we obtain
[tex]\[V_2=\frac{\left ( 350.0 \text{ kPa} \right )\left ( 200 \text{ mL} \right )}{\left ( 120.0 \text{ kPa} \right )}\] = 583 mL.[/tex]
It's not clear whether 200 mL (V₁) should be assigned three significant figures or one. I gave the answer to three significant figures; the answer to one significant figure would be 600 mL.
3. We use Boyle's Law once more here, but our word problem has us working backwards (it's also not explicitly mentioned that temperature remains constant, but it should be reasonable to assume so). The current pressure of the gas inside the bike tire is 150 atm at a volume of 700 mL . But we want to know what the initial pressure of the gas was at a volume of 1000 mL. In other words, we want to solve for the P₁ in Boyle's Law:
[tex]P_1=\frac{P_2V_2}{V_1}.[/tex]
Since the volume of the gas had decreased from 1000 mL (V₁) to 700 mL (V₂), and the pressure and volume of a gas at a constant temperature are inversely proportional, we would expect the pressure of the gas to have increased; that is, our P₁ should be less than 150 atm.
[tex]\[P_1=\frac{\left ( 150 \text{ atm} \right )\left ( 700 \text{ mL} \right )}{\left ( 1000 \text{ mL} \right )}\] = 105 atm.[/tex]
A 334 mL sample of hydrogen was collected over water at 23C on day when the atmospheric pressure was 756 mm Hg.The vapor pressure of water under these conditions is 17.54 mm Hg. What volume, in liters, will the dry hydrogen ( No water vapor) occupy at STP?
Answer:
0.299 L
Explanation:
We'll begin by calculating the pressure of dry gas. This can be obtained as follow:
Measured pressure = 756 mm Hg
Water vapor pressure = 17.54 mm Hg
Pressure of dry gas =?
Pressure of dry gas = (Measured pressure) – (Water vapor pressure)
Pressure of dry gas = 738.46 mmHg
Finally, we shall determine the volume occupied at STP. This can be obtained as follow:
Initial volume (V₁) = 334 mL = 334 / 1000 = 0.334 L
Initial pressure (P₁) = 738.46 mmHg
Initial temperature (T₁) = 23 °C = 23 °C + 273 = 296 K
Final pressure (P₂) = 760 mmHg
Final temperature (T₂) = 273 K
Final volume (V₂)
P₁V₁/T₁ = P₂V₂/T₂
738.46 × 0.334 / 296 = 760 × V₂/273
Cross multiply
296 × 760 × V₂ = 738.46 × 0.334 × 273
224960 × V₂ = 67334.2597
Divide both side by 224960
V₂ = 67334.2597 / 224960
V₂ = 0.299 L
Thus, the volume of the dry gas st STP is 0.299 L.