Answer:
Batteries convert chemical energy into electrical energy. Polarization is a defect that occurs in simple electric cells due to the accumulation of hydrogen gas around the positive electrode. In simple cells, hydrogen gas is evolved as a result of chemical reactions taking place inside the cell
Which of the following is TRUE about most gases?
1) They expand to completely fill their container.
2) They cannot be compressed.
3) All of their particles are the same size.
4) They have a fixed volume.
5) Their particles are very close together.
Explanation:
I think it is the first option
Answer:
1) They expand to completely fill their container. :)
Explanation:
What is the molarity of a solution made by adding :1.565 moles of PbN03 to 500 mL
Answer:
This question is a bit vague. We're not told if 500ml is the volume of the solution and additional info is not given to calculate the volume of pbNo3 being added.
If you solve with 500ml as the volume of solution ... You'll have the answer below.
Molarity=moles of solutes/Volume of solvent(in litres)
moles of solute given=1.565moles
Volume = 500ml. There's 1000ml to a litre. Dividing by 1000ml to convert to Litres... You have 0.5L
Molarity = 1.565/0.5
=3.13M
21 Organs consist of cells and tissues that have been adapted to perform a specific function in living organisms. The stomach is a muscular organ that is located on the left side of the upper abdomen. The stomach secretes acid and enzymes that help in the digestion of food. In simple terms, the stomach is a digestive sac. Even though the stomach has an important role in food digestion, it cannot perform the process all on its own. It depends on other organs such as the salivary glands, esophagus, liver, and intestines to help complete the process. Each organ has its own specific job, but together they make up an organ system. An organ system is a group of organs that work together to perform one or more functions. Which of the following describes the role of the immune system in the body? A. It gets rid of wastes that the body produces. B. It uses electrical signals to control body functions. C. It uses chemical messages to control body functions. D. It gets rid of pathogens that invade the body.
Answer:
The correct answer is - D. It gets rid of pathogens that invade the body.
Explanation:
Like all other organ systems, the immune system is an organ system that involves several special organs that helps in fighting any foreign object or infection that invades our body. This organ system produces specific cells or chemicals to fight or kill the microbes, and unnatural change takes place in the body.
The organs involved in the immune system are lymphocytes or white blood cells, the complement system, antibodies, the lymphatic system the thymus, bone marrow, and the spleen.
All these combinedly helps in fighting, killing the microbes or infections that occur in the body, and correct the physiological changes that occur in the body to get rid of pathogens that invade the body.
You are given a bottle of NaOH of an unknown concentration. You are tasked with determining the concentration of this solution. You weigh out 0.3175 g of KHP (MW = 204.2 g/mol) and dissolve it in 40 mL of water. You add phenolphthalein to the solution as an indicator. You preform your titration and determine that it requires 19.45 mL of the unknown NaOH solution to reach the endpoint. From this information, calculate the concentration of the unknown solution.
Answer:
0.07975 M NaOH
Explanation:
First determine the molarity of your acid, KHP. Convert grams to moles using the MW given and then divide by the volume of water.
0.3175 g KHP • (1 mol KHP / 204.2 g KHP) = 0.001555 mol KHP
0.001555 mol KHP / 0.040 L = 0.03888 M KHP
The reaction between KHP and NaOH is one-to-one, so you can just use M1V1 = M2V2 to solve for M2 (the molarity of NaOH).
M1 = 0.03888 M KHP
V1 = 40 mL
M2 = ? M NaOH
V2 = 19.45 mL NaOH
(0.03888 M KHP)(40 mL) = M2(19.5 mL NaOH)
M2 = 0.07975 M NaOH
number of atoms per unit cell in face centred cube is
Answer: 4 atoms is the answer. I hope it helped you.
Explanation:
Tectonic plates interact with each other and can create landforms. TRUE/FALSE
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Answer: True
I hope this helped!
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Answer:
true
Explanation:
15 The Following statement describes which body system? It also produces blood cells, and stores calcium. It regulates endocrine as well. This specific system uses all bones & joints in your body. A. The Lymphatic System B.The Muscular System C.The Reproductive System D.The Skeletal System
how many mass extension of ocean animals have there been in the last 400-500million years
Answer:
Explanation:
Around 439 million years ago, 86% of life on Earth was wiped out. Scientists believe two major events resulted in this extinction: glaciation and falling sea levels. Some theories suggest that the Earth was covered in such a vast quantity of plants that they removed too much carbon dioxide from the air which drastically reduced the temperature. Falling sea levels were possibly a result of the Appalachian mountain range forming. The majority of the animal life lived in the ocean. Trilobites, brachiopods, and graptolites died off in large numbers but interestingly, this did not lead to any major species changes during the next era.
A scientific article about the universe will most likely describe the universe as____?
Answer:
planet asteroid
Explanation:
planet asteroid
How was the position of planet Uranus predicted?
Upon studying the orbit of Uranus more closely, astronomers realized its orbit was being affected by the presence of another very large mass - so the hunt was on for another large planet. He sent his prediction to the Astronomer Royal, Sir George Airy, who passed it on to an 'observer'.
más inteligente o gracias por favor :)) <33 / brainliest or a thank you please :)) <33
The position of Uranus was predicted by determining the position of a larger mass ( Neptune ) exerting a gravitational push on Uranus
Uranus is the 7th planet in the galaxy it was initially discovered with the aid of a telescope by an astronomer whom initially thought it was a star.
The position of Uranus was predicted when an astronomer ( John Couch Adams ) and his colleague predicted the gravitational effect on Uranus from another larger mass ( Neptune ). they discovered the position of the larger mass affecting the orbit of Uranus and the position of this larger mass ( Neptune ) was used to predict the position of Uranus in the galaxy.
Hence we can conclude that the position of Uranus was predicted by determining the position of a larger mass ( Neptune ) exerting a gravitational push on Uranus
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The half-life of I-37 is 8.07 days. If 25 grams are left after 40.35 days, how many grams were in the original sample?
Answer:
800 g
Explanation:
We can express the decay of I-37 using the formula:
Final Mass = Initial Mass * [tex]0.5^{\frac{Time}{Half-Life} }[/tex]We input the data:
25 g = Initial Mass * [tex]0.5^{(\frac{40.35}{8.07})}[/tex]And solve for Initial Mass:
25 g = Initial Mass * [tex]0.5^{5}[/tex]25 g = Initial Mass * 0.03125Initial Mass = 800 gMeaning that out 800 grams of I-37, only 25 will remain after 40.35 days.
water from a town is suspected to contain chloride ions but not sulphate ions . describe how the presence of the chloride ions in the water can be shown
Answer:
See Explanation
Explanation:
The presence of chloride ions in water can be established by adding dilute trioxonitrate V acid to a sample of the water in drops followed by aqueous silver trioxonitrate V.
If a white precipitate is formed, which is soluble in excess aqueous ammonia solution, then the presence of chloride ion in the water sample is ultimately confirmed.
What can be different between products and reactants in a balanced equation?
a) The total mass of products and reactants
b) The total moles of each element present in the reactants and in the products.
c) The number of molecules in the reactants and in the products
Answer:
b) The total moles of each element present in the reactants and in the products.
Explanation:
Hello there!
In this case, since the law of conservation of mass is used to realize that the mass, atoms and molecules of all the species involved in a chemical reaction must be the same at both reactants and products, we can see that a and c stand for those that must be equal; thus, we infer that the moles can be different as they stand for the amount of substance which is related to the mass via molar masses. Therefore, the answer would be b) The total moles of each element present in the reactants and in the products.
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A 1.757-g sample of a / alloy was dissolved in acid and diluted to exactly 250.0 mL in a volumetric flask. A 50.00-mL aliquot of the diluted solution was brought to a pH of 10.0 with an / buffer; the subsequent titration involved both cations and required 28.89 mL of 0.06950 M EDTA. A second 50.00-mL aliquot was brought to a pH of 10.0 with an / buffer, which also served to mask the ; 19.07 mL of the EDTA solution were needed to titrate the . Calculate the percent and in the sample.
Answer:
78.14% Pb²⁺ and 21.86% of Cd²⁺
Explanation:
The first titration involves the reaction of both Pb²⁺ and Cd²⁺
In the second titration, as the buffer is HCN/NaCN, the Cd²⁺ precipitates as Cd(CN)₂ and the only ion that reacts is Pb²⁺
In the first titration:
Moles EDTA = Moles Pb²⁺ and Cd²⁺:
28.89mL = 0.02889L * (0.06950moles / L) = 2.008x10⁻³ moles in the aliquot. In the sample:
2.008x10⁻³ moles * (250.0mL / 50.0mL) =
0.01004 moles = Pb²⁺ + Cd²⁺ (1)
In the second titration:
19.07mL = 0.01907L * (0.06950mol / L) = 1.325x10⁻³ moles Pb²⁺ in the aliquot. In the sample:
1.325x10⁻³ moles Pb²⁺ * (250.0mL / 50.0mL) =
6.626x10⁻³ moles Pb²⁺
That means the moles of Cd²⁺ are:
0.01004 moles = Cd²⁺ + 6.626x10⁻³ moles Cd²⁺
3.413x10⁻³ moles Cd²⁺
The mass of each ion is:
Cd²⁺ -Molar mass: 112.411g/mol-:
3.413x10⁻³ moles Cd²⁺ * (112.411g / mol) =
0.384g of Cd²⁺
Pb²⁺ -Molar mass: 207.2g/mol-:
6.626x10⁻³ moles Pb²⁺ * (207.2g / mol) =
1.373g of Pb²⁺
The percent mass of each ion is:
1.373g Pb²⁺ / 1.757g = 78.14% Pb²⁺
And:
0.384g of Cd²⁺ / 1.757g * 100 = 21.86% of Cd²⁺
Which trend is observed as the first four elements in Group 17 on the Periodic Table are considered in order of increasing atomic number?
1. Electronegativity decreases
2. First ionization energy increases
3. The number of valence electrons increases
4. The number of electron shells decreases
A sample of hydrogen takes up 34.0 dm3 of space when it is under 500.0 kPa of pressure. When the pressure is changed to 340.0 kPa, what is the new volume? dm3 H2
Answer:
50 dm³
Explanation:
Assuming constant temperature, we can solve this problem using Boyle's law, which states:
P₁V₁=P₂V₂Where in this case:
P₁ = 500.0 kPaV₁ = 34.0 dm³P₂ = 340.0 kPaV₂ = ?We input the data:
500.0 kPa * 34.0 dm³ = 340.0 kPa * V₂And solve for V₂:
V₂ = 50.0 dm³Thus the answer is 50.0 dm³ H₂.
When 86.5 g of calcium chlorate decomposes into calcium chloride and oxygen, how many grams of oxygen are produced? Ca(ClO3)2 → CaCl2 + O2
Answer:
40.1 g
Explanation:
The balanced equation is:
Ca(ClO₃)₂ → CaCl₂ + 3O₂First we convert 86.5 g of calcium chlorate into moles, using its molar mass:
86.5 g Ca(ClO₃)₂ ÷ 206.98 g/mol = 0.418 mol Ca(ClO₃)₂Then we convert Ca(ClO₃)₂ moles into O₂ moles, using the stoichiometric coefficients of the balanced reaction:
0.418 mol Ca(ClO₃)₂ * [tex]\frac{3molO_2}{1molCa(ClO_3)_2}[/tex] = 1.254 mol O₂Finally we convert O₂ moles into grams:
1.25 mol O₂ * 32 g/mol = 40.1 g O₂Determine whether each described process is endothermic or exothermic.
a. Ice melts into liquid water
b. A process with a calculated positive q.
c. Wood burns in a fireplace.
d. A process with a calculated negative q.
e. Acid and base are mixed, making test tube feel hot.
f. Solid dissolves into solution, making ice pack feel cold
Answer:
Ice melts into liquid water- endothermic
A process with a calculated positive q - endothermic
Wood burns in a fireplace - exothermic
A process with a calculated negative q - exothermic
Acid and base are mixed, making test tube feel hot - exothermic
Solid dissolves into solution, making ice pack feel cold - endothermic
Explanation:
An endothermic process is one in which heat is absorbed from the surroundings. The absorption of heat means that heat is removed from the surroundings hence the surroundings feel cool. When heat is absorbed, q is positive.
An exothermic process is one in which heat is released to the surroundings. The evolution of heat means that heat is released into the surroundings hence the surroundings feel hot . When heat is evolved, q is negative.
c) If 21.0 g of potassium reacts with 62.5 g of barium nitride, what mass of potassium nitride will be produced?
Explanation:
21.0 g of potassium reacts with 62.5 g of barium nitride, what mass of potassium nitride will be produced
6. What is the number of moles of KF in a 29 gram sample?
a. 59.0 mols
C. 2.0 mols
b. 470 mols
d. 1684.9 mols
what is the volume in liters at 422K if n and P does not change?
Answer:
0.75 L
Explanation:
V1/T1 = V2/T2
V1 = 0.520 L
T1 = 18 C = 291 K (make sure to convert to Kelvin by adding 273 to the Celsius temperature)
V2 = ?
T2 = 422 K
Solve the equation for V2
V2 = V1T2/T1
V2 = (0.520 L)(422 K) / (291 K) = 0.754 L ≈ 0.75 L (since it says to only give two significant figures)
During the reaction of 2,4-dinitrofluorobenzene with methoxide in methanol it was observed that it occurs at a significantly higher rate than the same reaction of 3,4-dinitrofluorobenzene. Explain the observation with a detailed mechanism and convincing structural arguments.
Answer:
Explanation:
your not so smart
Compounds consist of two or more elements. Which of the following properties must each of the elements in a compound
have?
A. solubility
B. conductivity
c. high density
D. chemical reactivity
0.500 mole of copper(II) sulfate contains
moles of O.
Answer:
2 mol
Explanation:
There are 4 mols of O per one sulfate so since there is only one sulfate you simply times 4 by .5 to get the number of mol
How does increasing and decreasing the temperature affect the kinetic energy of molecules? How does this impact heat
transfer?
Answer: As the temperature of a molecular system increases, the kinetic energy of molecules also increase. Also as the temperature of a molecular system decreases, the kinetic energy of the molecules will also decrease.
Explanation:
James Clerk Maxwell developed the kinetic-molecular theory (KMT) of gases. In this theoey, five assumptions concerning an ideal gas was made. One of the them was that," the average kinetic energy of the gas molecules is proportional to the temperature of the gas". This simply means that a s the temperature of a molecular system increases, the kinetic energy of molecules also increase. Also as the temperature of a molecular system decreases, the kinetic energy of the molecules will also decrease.
Also another scientist known as Rudolf Clausius incorporated energy into the kinetic theory. He proposed that heat is a form of energy that affects the temperature of matter by changing the motion of molecules in matter.
Heat is defined as the flow of energy which is caused by difference in temperature.
In conclusion, when the temperature of a system is increased, the collision of the molecules with one another and the walls of their container increases as more molecules gain more heat energy at higher temperature. While as the temperature of the system decreases, the collision of the molecules will also decrease as molecules lose heat energy at lower temperature.
Answer:
Temperature increases the average kinetic energy of the atoms as well as molecules increases because when the temperature increases the collision between the atom and molecules increases and particles may collide with one another.
because it may associate with the thermal energy when thermal energy increases because of the motion of the gas particle and may initiate the kinetic energy of the gas.
when the temperature goes increasing the movement of the particle is at a very high rate, especially in gas and then solids, and especially this must be increased when the endothermic reaction is involved this must proceed such a reaction that the temperature results in to increase in the average kinetic energy.
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What product(s) would be formed when these are the reactants? BaF2 + Cl2
If I contain 2 moles of gas in a container with a volume of 30 liters and at a temperature of 337 K, what is the pressure inside the container?
Answer:
1.84
Explanation: just input the value into the formula pv=nrt
p*30=2*0.08206*337 then divide both sides by 30 and get 1.84
2.0 M H2SO4 solution.calculate the pH
Answer:
-.30
Explanation:
H2SO4/sulfuric acid/dihydrogen sulfate is a strong acid, meaning that it easily releases an H+. You have to be careful with this problem, however, as H2SO4 is really only a strong acid for one of its hydrogens. In other words, after it becomes HSO4- upon releasing an H+, it is no longer a strong acid and therefore should not be factored into our calculation.
Now, moving onto the calculation, there are two key things we need to carry it out. First is the pH equation. pH = -log [H+]. And second is the concentration of H2SO4, which is equivalent to the concentration of that H+ released: 2.0 M. Simply plug in your values.
pH = -log [2.0].
pH = -.30
How many grams of KI are needed to prepare 2,000. grams of an aqueous solution
containing 25 parts per million (ppm) of solute?
Answer:
[tex]m_{solute}=0.05g[/tex]
Explanation:
Hello there!
In this case, according to the equation for the calculation of the parts per million:
[tex]ppm=\frac{m_{solute}}{m_{solution}} *1x10^6[/tex]
It is possible to solve for the mass of KI (solute) as shown below:
[tex]m_{solute}=\frac{ppm*m_{solution}}{1x10^6}[/tex]
Thus, we plug in to obtain:
[tex]m_{solute}=\frac{25*2,000g}{1x10^6} \\\\m_{solute}=0.05g[/tex]
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