Answer would be C, Physical Change, it's similar to crumpling up a piece of paper
physical change is the answer
98 POINTS!
Based on the data (below)
1) which reaction is the most efficient and why?
2) which reaction data is in error and what is the correction?
1) Number of moles of product, carbon dioxide, is the same as that of vinegar. So the most efficient reaction is the one with the less amount of baking soda. So RXN 1 is the most efficient.
2) Number of moles of product, carbon dioxide, is the same as that of vinegar; except RXN 5. There is an error in the number of moles of carbon dioxide. It should be 0.05034.
Answer:
1) 1 is most efficient
Explanation:
efficiency is the ratio bet. reactants n products. adding vinegar n baking soda then dividing by co2, 1 gives the largest no.
2) 5 has different vinegar n co2 ratio - they are the same in the other 4. so for 5, the co2 should be 0.05034.
Chalcopyrite, the principal ore of copper (Cu), contains 34.63 percent Cu by mass. How many atoms of Cu can be obtained from 5.11 x 103 kg of ore? A) 1.68 x 1028 Cu atoms B) 1.68 x 1025 Cu atoms C) 6.77 x 1031 Cu atoms D) 6.77 x 1034 Cu atoms
Answer:
A) 1.68 x 10²⁸ Cu atoms.
Explanation:
∵ The mass of Cu in the chalcopyrite ore = mass of the ore x weight fraction of Cu.
Weight fraction of Cu = Weight % / 100 = 34.63 /100 = 0.3463.∴ The mass of Cu in the chalcopyrite ore = mass of the ore x weight fraction of Cu = (5.11 x 10³ kg)(0.3463) = 1.77 x 10³ kg.
We need to calculate the no. of moles of Cu atoms:n of Cu = mass/atomic mass of Cu = (1770 x 10³ g) / (63.54 g/mol) = 27.853 x 10³ mol.
We have that every mole of an element contains Avogadro's no. of atoms (6.022 x 10²³).∴ 27.853 x 10³ mol of Cu contains = (27.853 x 10³ mol)(6.022 x 10²³) = 1.677 x 10²⁸ Cu atoms ≅ 1.68 x 10²⁸ Cu atoms.
What is the molar concentration of the acid if 35.18 mL of hydrochloric acid was required to neutralize 0.745 g of ALUMINUM hydroxide?
The solution will be 0.27M hydrochloric acid
How many moles are contained in 3.131 x 10^24 particles?
.5 moles.... because 1mole has 6.022×10^23 particles
Answer:
.5
Explanation: just trust
1.Which of these questions can be answered using science? (2 points)
What is the best career?
Does water exist on Venus?
Should the use of automobiles be stopped?
Which is the most interesting subject to study?
2.Sarah plans to go on an outing with her friends. On Saturday morning, the sky was cloudy and Sarah's barometer indicated that the air pressure was falling. When air pressure falls, it indicates the weather conditions will decline. The air pressure kept falling for the next three days and then started rising on the fourth day. Based on scientific knowledge, which of these was the most favorable day for Sarah to go on an outing? (2 points)
Saturday
Sunday
Wednesday
Tuesday
3.Which of these questions can be answered using scientific methods? (2 points)
4.Who is the best author in English?
Should all students take the same classes?
Which is the tastiest flavor of ice cream?
What would be the effect of a hurricane?
Predictions about the future based on the lines on the palm of the hand is an example of (2 points)
pseudoscience
mathematics
astronomy
biology
5. Scientists believe that Earth is becoming warmer. This idea will become unacceptable over time if (2 points)
it is not discussed in a scientific forum
scientific evidence supports a new idea
scientists propose alternative hypothesis
new instruments are invented to measure temperature
6.How does science help society? (2 points)
It helps answer questions on the purpose of human life.
It helps society take reasonable decisions.
It proves that all other subjects are useless for society.
It proves that all questions can be answered using science.
7.A theory is accepted by scientists when (2 points)
it becomes a law
it can be shown with a model
it describes how nature works
it is supported by adequate data
One scientist discovered a new theory on the evolution of the universe. What is the next step for the scientist to take? (2 points)
transform the results of the theory into universal laws of nature
inform the scientific community so they can verify the results
call a press conference to make the discovery popular among people
encourage scientists worldwide to find an appropriate application for the results
8. A scientist studies a model of a widely accepted theory about the position of planets and sun. The model would most likely help the scientist to (2 points)
prove that the theory would not change in the future
demonstrate how the theory can be changed into a law
understand facts which cannot be easily observed
prove that all other facts about the universe are incorrect
1. Questions that can be answered using science include:
- Does water exist on Venus?
- Should the use of automobiles be stopped?
2. Based on scientific knowledge, the most favorable day for Sarah to go on an outing would be Wednesday, as the air pressure started rising on the fourth day, indicating improving weather conditions.
3. Questions that can be answered using scientific methods include:
- What would be the effect of a hurricane?
4. Predictions about the future based on the lines on the palm of the hand is an example of pseudoscience.
5. The idea that Earth is becoming warmer will become unacceptable over time if scientific evidence supports a new idea.
6. Science helps society by helping society take reasonable decisions.
7. A theory is accepted by scientists when it is supported by adequate data.
The next step for the scientist who discovered a new theory on the evolution of the universe would be to inform the scientific community so they can verify the results.
8. A model of a widely accepted theory about the position of planets and sun would most likely help the scientist to understand facts which cannot be easily observed.
A person's _____ changes as he travels from the earth to space, but his _____ remains the same. mass, weight weight, mass mass, height height, weight
A person's weight changes as he travels from the earth to space, but his mass remains the same. Weight is a cause of gravity pulling down on a mass.
Answer:
I think it's the other way around
Explanation:
Match the salt with the acid and base used to form it in a neutralizing reaction.
K2SO4
H3PO4 and NaOH
KOH and H2SO4
HPO4 and KOH
NaBr
NaOH and HBr
KOH and H2SO4
NaCl and HSO4
K2SO4 - KOH and H2SO4
NaBr - NaOH and HBr
Explanation;Salts are compounds that contain positively charged ions and negatively charged ions. That is; they consist of the positive ion of a base and the negative ion of an acid. Salts may be produced when acids and bases are combined together in equal proportions, a process called neutralization.During neutralization reactions an acid reacts with a base to form a salt and water as the only products.Answer:
1)K2SO4 - B) KOH and H2SO4
2)NaBr - A) NaOH and HBr
if 1.00 mole of water is produced how many moles of hno3 are used
I think that the answer would be 12
Two moles of nitric acid can be used to produce one mole of water.
What is a mole?A mole can be described as an international scientific standard unit that can be utilized to determine a given count of particles. The particles counted can be generally identical entities, individually distinct.
A mole can be used to determine a large number of quantities of atoms, molecules, ions, or subatomic particles. The amount of substance can be measured in terms of mole as elementary entities of a given substance in a sample.
The number of chemical entities present in 1 mole is equal to 6.023 × 10²³ is Avogadro’s constant.
Given, the reaction of the formation of water from nitric acid:
[tex]4HNO_3 \longrightarrow 4 NO_2 + 2 H_2O +O_2[/tex]
Given, the number of mol of water = 1 mol
2 mol of water is produced from nitric acid = 4 mol
1 mol of water will be produced from nitric acid = (4/2) × 1 = 2 mol
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If 260 mL of O2 gas is collected at 21 degrees Celsius and 101.3 kPa, what volume would this gas occupy at STP?
By using the combined gas law, we can determine that the volume of the gas under standard conditions of temperature and pressure (STP) would be approximately 242 mL.
Explanation:The solution to this question can be found by using the combined gas law which connects the variables of pressure, volume and temperature. The combined gas law is typically written as P1V1/T1 = P2V2/T2 where P is pressure, V is volume and T is temperature. P1, V1, and T1 are the initial pressure, volume and temperature, and P2, V2, and T2 are the final pressure, volume and temperature.
In this case, we know the initial volume (V1) as 260 mL, the initial temperature (T1) as 21 degrees Celsius which converts to 294.15 K, and the initial pressure (P1) as 101.3 kPa. At STP, the final pressure (P2) is 101.325 kPa and the final temperature (T2) is 273.15 K.
Inputting these values into the combined gas law formula, we get: (101.3 kPa * 260 mL) / 294.15 K = (101.325 kPa * V2) / 273.15 K. Upon solving this equation, we find that under standard conditions of temperature and pressure (STP), the volume (V2) is approximately 242 mL.
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PLEASE HELP WITH THIS CHEMISTRY QUESTION:
For 550.0 mL of a buffer solution that is 0.170 M in CH3CH2NH2 and 0.150 M in CH3CH2NH3Cl, calculate the initial pH and the final pH after adding 0.020 mol of HCl.
Kb for ethylalamine = 5.6 x 10^-4.
pKb = -log( 5.6 x 10^-4.) = 3.25
pOH = 3.25 + log (0.295/0.325)
pOH = 3.207
14 -3.207 = 10.79 for Initial
lets see for final
0.325 * 0.28 = 0.091mol CH3CH2NH2
0.295 * 0.28 = 0.0826 mol CH3CH2NH3Cl
0.0826 - 0.005 = 0.0776mol CH3CH2NH3Cl
0.091 + 0.005 = 0.096 mol CH3CH2NH2
pOH = 3.25 + log(0.0776 / 0.096)
pOH = 3.157
pH =10.84 for final
I need help ASAP
1.Minerals are generally (2 points)
A.solids
B.liquids
C.gases
D.plasmas
2.Which of these statements is correct about water and oil? (2 points)
A.Water is not a mineral because it is a liquid but oil is a mineral because it is formed under the ground by natural processes.
B.Both water and oil are minerals because they are natural materials with a definite chemical composition.
C.Water is a mineral because it has a definite chemical composition but oil is not a mineral because it is organic.
D.Both water and oil are not minerals because they are liquids
3.What mineral is most likely used to make the plumbing pipe? (2 points)
A.talc
B.zinc
C.quartz
D.copper
4.Which of these is the correct next step to complete the diagram? (2 points)
A.Put an arrow labeled cools and crystallizes, pointing from igneous rocks to sediments.
B.Put an arrow labeled cools and crystallizes, pointing from sedimentary rocks to sediments.
C.Put an arrow labeled heat and pressure, pointing from igneous rocks to metamorphic rocks.
D.Put an arrow labeled heat and pressure, pointing from metamorphic rocks to sedimentary rocks.
5.
Igneous rocks are formed due to the (2 points)
A..cooling of magma
B.weathering of rocks
C.changes in pressure
D.changes in temperature
6.David plans to grow corn on his farm. Corn grows best in clay loam soil. Which of these is the most likely soil sample that David would select to grow corn? (2 points)
A.sample containing 30 percent sand, 35 percent clay, and 35 percent silt
B.sample containing 25 percent sand, 15 percent clay, and 60 percent silt
C.sample containing 40 percent sand, 15 percent clay, and 45 percent silt
D.sample containing 55 percent sand, 30 percent clay, and 15 percent silt
1. a
2. d
3. d
4. c
5. a
6. a
Answer:
A.solids
D.Both water and oil are not minerals because they are liquids
D.copper
C.Put an arrow labeled heat and pressure, pointing from igneous rocks to metamorphic rocks.
A..cooling of magma
A.sample containing 30 percent sand, 35 percent clay, and 35 percent silt
What volume of 0.12M Ba(OH)2 is needed to neutralize 12.2 mL of 0.25M HCl? *
25 ml
13 ml
50ml
125 ml
50 ml es el resultado
To neutralize 12.2 mL of 0.25M HCl, approximately 12.7 mL of 0.12M Ba(OH)2 is required. The closest option provided is 13 mL, which is correct based on the stoichiometry of the reaction and the concentrations involved.
Explanation:To determine the volume of 0.12M Ba(OH)2 needed to neutralize 12.2 mL of 0.25M HCl, we must first write out the balanced chemical equation for the reaction:
Ba(OH)2 (aq) + 2 HCl (aq) → BaCl2 (aq) + 2 H2O (l)
From the equation, we see that one mole of Ba(OH)2 reacts with two moles of HCl. Next, we calculate the number of moles of HCl that will be neutralized:
Moles of HCl = Volume (L) × Concentration (M)
Moles of HCl = 0.0122 L × 0.25 M = 0.00305 mol
Based on the stoichiometry of the balanced equation, we need half the number of moles of Ba(OH)2 to neutralize the HCl.
Moles of Ba(OH)2 = 0.00305 mol HCl × (1 mol Ba(OH)2/2 mol HCl) = 0.001525 mol
Then, we calculate the volume of Ba(OH)2 solution:
Volume of Ba(OH)2 = Moles of Ba(OH)2/Concentration of Ba(OH)2
The volume of Ba(OH)2 = 0.001525 mol/0.12 M = 0.012708 L, which is approximately 12.7 mL.
Therefore, the volume of 0.12M Ba(OH)2 needed to neutralize 12.2 mL of 0.25M HCl is closest to 13 mL, which is one of the given options.
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In the final chemical equation, NaCl and O2 are the products that are formed through the reaction between Na2O and Cl2. Before you can add these intermediate chemical equations, you need to alter them by
the answer to the question is b
Answer : The correct option is, (B) multiplying the equation first by 2.
Explanation :
The balanced final chemical reaction will be,
[tex]2Na_2O(s)+2Cl_2(g)\rightarrow 4NaCl(s)+O_2(g)[/tex]
The two intermediate chemical reaction are give :
(1) [tex]2Na(s)+Cl_2(g)\rightarrow 2NaCl(s)[/tex]
(2) [tex]2Na_2O(s)\rightarrow 4Na(s)+O_2(g)[/tex]
First multiplying the equation (1) by 2, we get
[tex]4Na(s)+2Cl_2(g)\rightarrow 4NaCl(s)[/tex]
Now adding both the equations, we get
[tex]2Na_2O(s)+4Na(s)+2Cl_2(g)\rightarrow 4Na(s)+O_2(g)+4NaCl(s)[/tex]
The final chemical reaction are :
[tex]2Na_2O(s)+2Cl_2(g)\rightarrow 4NaCl(s)+O_2(g)[/tex]
Hence, the correct option is, (B) multiplying the equation first by 2.
What is the number of moles of solute in 250 mL of a 0.4 M solution? Don't forget the unit.
Using the equation we get something like this:
M = moles of solute/ liters of solution
But we need the number of moles of solute right? so we gotta arrange the equation to make it fit our needs.
M x liters of solution = moles of solute
M = mol/L
Liters of solution = L
moles of solute = mol
We have the M which stands for the molar mass in mol/L (0.4M)
And we also have the mL which are the liters of our solution, yet to be converted into liters. Let's divide them by a 1000 to make it into liters.
250mL / 1000 = 0.250L
Now we can multiply them! and find the number of moles of solute by replacing them, remember M can be changed into m/mol, because it's pretty much the same but written in another way.
0.4mol/L x 0.250L = 0.1 mol
The liters canceled, and we end up with mol. So, the answer is 0.1 mol.
Answer: 0.1 mol
Explanation: For gradpoint :)