Answers
Answer:
What substance changed physically under all three condition? Copper Wire
What substance changed chemically under all three condition? Steel Wool
What evidence indicates a chemical reaction is occurring? New gases are produced; A phase change has occurred; A color change
Select the three answers that are examples of a chemical reaction. The mixing of an acid and base shows an increase in temperature; after baking bread there is a new odor or smell; when hair is bleached it changes to a lighter color
Which data supports this inference? Baking soda dissolving; A gas formed, creating bubbles
Which experiment best shows evidence of energy being released in a chemical reaction? Heat and light are given off when paper is burned
Which experiment likely resulted in the formation of a precipitate? Two solutions are mixed together and a yellow solid forms
The BEST evidence for a chemical reaction is the formation of a new substance.
Explanation:
2. When heat and light are being given off, energy is being released. Paper burning is a chemical reaction b/c when paper is burnt, it is a new substance and the act can't be undone.
3. When a yellow solid forms, that solid is the participate.
4. You will for sure have a chemical reaction if a new substance is created.
5. Copper wire changed physically b/c the copper wire can be returned to its original condition in all of these situations and no new substance was formed. Steel Wool changed chemically b/c it can't be returned to its original state under any condition and new substances were formed every time.
6. New substances formed indicate a chemical reaction. A color change also is an indication of a chemical reaction.
7. When a substance can't be turned into its original position or a new substance is produced, a chemical reaction occurred.
Related Questions
Conduction does not work well in metals.
True or False
Answers
Question :
Conduction does not work well in metals. True or FalseAnswer:
False, because:
Thermal conduction is defined as the transport of energy due to random molecular motion across a temperature gradient. It is distinguished from energy transport by convection and molecular work in that it does not involve macroscopic flows or work-performing internal stresses.
Or in other words, Conduction is the transfer of heat between two parts of a stationary system, caused by a temperature difference between the parts.
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Suppose you have an ice cube with mass of 8.00 g at a temperature of 295 K. If that ice cube is heated until it is completely converted to steam at 373 K how many joules of heat must be added ?
Answers
Explanation:
In order to be able to answer this question, you must know the value of water's enthalpy of fusion, ΔHfus
Which have a mass of 0 amu?
A. Protons
B. Neutrons
C. Electrons
D. Protons and neutrons
E. Protons and electrons
F. Neutrons and electrons
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Answers
Answer:
c
Explanation:
Answer:
C. electrons. They also have a charge of -1
photosynthesis is chemical change that happens in the plant what substance within the plant allows light energy to be captured
Answers
Explanation:
Sunlight provides the energy needed for photosynthesis to take place. In this process carbon dioxide and water are converted into oxygen (a waste product that is released back into the air) and glucose (the source of energy for the plant).
The periodic table notation for nitrogen (N) is shown below. An atom of nitrogen has how many neutrons?
N
Nitrogen
14.01
A.0 7 or 8
B.Cannot be determined with the information given.
C.7
D.14 or 15
Answers
22. Which of the following are examples of mixtures?
I
a jar of nuts and bolts
II trail mix consisting of a variety of nuts and dried fruits
III carbon monoxide gas coming out of a car's exhaust pipe
an
pare
A. I and II only
C. I and III only
B. I and III only
D. I, II, and I
23. Which of the following lists contains only individual elements?
A. water, sugar, and salt
B. carbon, copper, and iron
C. tomato juice, propane,
D. sulfuric acid, magnesium, and chocolate chip cookies
and soda pop
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Answer:
22.)B. l and lll only
23.)D.sulfuric acid, magnesium, and chocolate chip cookies
and soda pop
What is the amount of aluminum chloride produced from 40 moles of chlorine and excess aluminum?
Answers
Answer: Molar mass of Al = 26.98 g/mol
mass of Al = 12 g
mol of Al = (mass)/(molar mass)
= 12/26.98
= 0.4448 mol
According to balanced equation
mol of AlCl3 formed = moles of Al
= 0.4448 mol
Answer: 0.445 mol
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Explanation:
How many Noble gases are there?
Answers
Answer:
six noble gases
Here are five of the six noble gases: helium, neon, argon, kypton and xeon. They're all colourless and transparent. Krypton and xeon form compounds only with difficulty. Helium, neon and argon don't form compounds at all.
Answer:
There are in total 6 noble gases in the periodic table.
Namely,
1. Helium
2. Neon
3. Argon
4. Krypton
5. Xenon
6. Radon
what is the product for the synthesis reaction Na+O2
1-NaO
2-NaO2
3-Na2O
4-Na3O2
5-Na2O3
6-Na2O2
Answers
Escucho activamente a mis compañeros y compañeras, reconozco otros puntos de vista, los comparo con los míos y puedo modificar lo que pienso ante argumentos más sólidos.
Answers
Answer:
Explanation:
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Part II: Fill in the Blank-Complete each sentence; you may put more than one word in a
blank.
9. _____________ have a mass number of 0.
10. Particles found in the nucleus are called ______________________.
11. _____________________________ is when electrons are released by a hot filament.
12. The number of protons and neutrons in an element is called the _______________ number.
13. ____________________ was the first atomic bomb dropped.
14. _________________ would be an example of a spontaneous change to the nucleus.
15. _____________ decay results in the release of two protons and two neutrons.
16. __________________ are particles that would be attracted to a positively charged plate.
17. __________________________ coined the word radioactivity.
18. ____________________________________ is used to produced radioactive isotopes by
forcing nuclear reactions.
19. During __________________, the nucleus of a Uranium 235 atom is split into lighter
elements, neutrons, and energy.
20. _________________ are the fastest form of radiation.
21. The number of protons in an element is called the _______________ number.
22. Irene Curie used ___________________ as the source of alpha particles for her research.
23. Uranium goes through _____________ decay ____________ (a number) times to produce
Plutonium.
24. ________________ is a raw Uranium ore which was central to the discovery of radioactivity.
25. The ____________________ was cited in the letter signed by Einstein as having ore with
high concentrations of U-235.
Answers
Answer:
uh.. How many do you want done??
Explanation:
9. Neutrons
10. Protons and Neutrons
12. Atomic Mass / Mass Number
13. Little Boy over Hiroshima, Japan.
14. Spontaneous fission
15. Alpha decay
17. Marie Curie
19. Nuclear fission
20. Gamma rays
21. Atomic number
I’d probably know more of these if I paid attention more in my lessons/studies IMO, but here’s what I know 100% for those answers!
Chemistry question on enthalpy HELP!!!!
Answers
Answer: The enthalpy change for this reaction is, -803 kJ
Explanation:
The balanced chemical reaction is,
[tex]CH_4(g)+2O_2(g)\rightarrow CO_2(g)+2H_2O(g)[/tex]
The expression for enthalpy change is,
[tex]\Delta H=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)][/tex]
[tex]\Delta H=[(n_{CO_2}\times \Delta H_{CO_2})+(n_{H_2O}\times \Delta H_{H_2O})]-[(n_{O_2}\times \Delta H_{O_2})+(n_{CH_4}\times \Delta H_{CH_4})][/tex]
where,
n = number of moles
Now put all the given values in this expression, we get
[tex]\Delta H=[(1\times -394)+(2\times -242]-[(2\times 0)+(1\times -75)][/tex]
[tex]\Delta H=-803kJ[/tex]
Therefore, the enthalpy change for combustion of methane is, -803 kJ
A small beaker contains 50 milliliters of water
at 20°C. If three sugar cubes are placed in the
beaker, they will eventually dissolve. Which
action would speed up the rate at which the
sugar cubes dissolve?
F) Use less water initially.
G) Transfer the contents to a larger beaker.
H) Cool the water and sugar cubes to 5°C.
J) Heat and stir the contents of the beaker.
Answers
Explanation: heat makes things dissolve quicker
How many moles are in 5.5 x 10-23 molecules of H2O
Answers
Answer:
0.914moles
Explanation:
The number of moles in a substance can be got by dividing the number of atoms/molecules/particles by Avagadro's constant (6.02 × 10^23).
That is;
number of moles (n) = number of atom (nA) ÷ 6.02 × 10^23
According to this question, there are 5.5 x 10-23 molecules of H2O
n = 5.5 x 10^23 ÷ 6.02 × 10^23
n = 0.914 × 10^(23-23)
n = 0.914 × 10^0
n = 0.914 × 1
n = 0.914moles
Based in your knowledge of diatomic molecules, predict the decomposition of water. Note that the reaction is NOT balanced. Choose the correct one.
H2O = H + O
H2O = H2 + O2
H2O = H + O2
H2O = H2 + O
Answers
Answer:H2O = H2 + O
Explanation:
What is the purpose of the stairstep pattern on the periodic table of the elements?
Answers
Answer: The bold staircase in the periodic table allows us to classify which elements are metalloids.
Explanation: Additionally, it acts like a "divider" that allows us to properly distinguish the metals from the non-metals in the periodic table.
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9. Name the scientists that played a major role in the development of cell theory. *
Answers
Hope this helps
Have a great day/night
Ground water, the largest source of fresh water, is stored in bodies of rock and or sediment
a. porosity
b. sediment
c. particles
d. aquifers
i dont even know what this means
Answers
Answer:
particles
Explanation:
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Match the special cases of each gas law with its description. A law may be used more than once. In the equations, K is a constant.
A. Boyle's law
B. Charles's law
C. Avogadro's law
D. Dalton's law
____ P1 V1 = P2 V2
____ V/T = k
____ V1 / T1 = V2 / T2
____ V = kn
____ PV = k
____ Ptotal = P1 + P2 + P3 + .
Answers
The special cases of gas laws and its description includes:
A. Boyle's law: P1 V1 = P2 V2
B. Charles's law: V/T = k or V1 / T1 = V2 / T2
C. Avogadro's law: V = kn
D. Dalton's law: Ptotal = P1 + P2 + P3 + .
What is gas law?Gas laws are laws that relate a gas's pressure, volume, and temperature. Boyle's law, named after Robert Boyle, states that the pressure P of a gas varies inversely with its volume V at constant temperature, or PV = k, where k is a constant. Charles' law is named after J. -A. -C.
They also include; Gay-Lussac's Law, Avogadro's Law and Dalton's law of partial pressures.
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How does solar energy affect climate?
Answers
Answer:
It makes it things grow and it is renewable energy meaning that its infinite and will help life grow fruits grass and with that comes how animals live including us human how does it effect climate it make thing warm and sometimes hot and can cause thunder to make the place cool down sorry if wrong
why do molecules and atoms speed up when the amount of heat increases
Answers
Heat is the energy that a thing possesses as a result of the movement of its atoms and molecules, which are always bouncing off of one another and other objects. An object's atoms and molecules move more quickly when we add energy to it, which increases the object's energy of motion or heat.
The gas will travel more quickly in the container if the temperature is raised. This occurs as a result of the particles' increased kinetic energy caused by heating. There will be more collisions between particles if they are traveling faster.
A substance's atoms and molecules move more quickly when it is heated. Whether the substance is a solid, liquid, or gas, this occurs.
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Help! “Name 2 elements that can form the same type of ion as calcium. Explain”
Answers
Answer:
Beryllium and magnesium will show similar chemical reactions as calcium. Since these elements belong to same group II and also have two electrons in their outermost shell like calcium.
A closed container has 5.60 x 1023 molecules of oxygen gas (O2). How many moles is that?
Answers
Use the periodic table to determine which of the
following could be an isotope of bromine (Br).
Check all that apply.
Z = 79, A = 196
Z = 35, A = 79
A = 79, N =44
D Z = 44, N = 44
DONE
Answers
for an atom to be considered electrically neutral it must contain the same number of
Answers
How many significant figures are in this measurement: 1,250,500
Answers
2H20 → 2H2 + O2
Type of reaction?
Answers
Answer:
Notice how the elements splitIt is a decomposition reaction I do exams and quizzes if ur interestedHow many atoms of oxygen are in 75.6g of silver nitrate (AgNO3)?
Answers
Answer:
1.50x10^21 molecules O2
Explanation:
the structure and bonding of gold?
Answers
Answer:
metallic bonding
Explanation:
since it is a metal gold forms metalllic bonding.
Answer:
metalic bonding
Explanation:
500.0 mL of a gas is collected at 745 K. What will the volume be at standard temperature?
Answers
Answer:
183.22mL
Explanation:
Using Charles law equation, which is as follows:
V1/T1 = V2/T2
Where;
V1 = initial volume (mL)
T1 = initial temperature (K)
V2 = final volume (mL)
T2 = final temperature (K)
Note that standard temperature of a gas is 273K.
Hence, based on the provided information, V1 = 500.0mL, T1 = 745K, V2 = ?, T2 = 273K
Using the formula; V1/T1 = V2/T2
500/745 = V2/273
Cross multiply
V2 × 745 = 500 × 273
745V2 = 136500
V2 = 136500/745
V2 = 183.22
At standard temperature (273K), the new volume will be 183.22mL.
Answer:
183 ml
Explanation: