Answer:
The part of the experiment that is set to compare data
Explanation:
The controlled variable is what stays constant throughout an experiment. You use the controlled variable to compare the new data to see what happened during whatever reaction you could say.
Which substance is the least toxic?
a. chlorine (LD50 = 850 mg/kg)
b. vitamin A (LD50 = 2000 mg/kg)
c. cola (LD50 = 140 mg/kg)
d. aspirin (LD50 = 200 mg/kg)
Answer:
I believe it's D. I searched up a lethal table chart and it states Aspirin is even more toxic than chlorine. As for the other two, it didn't specifically state it was toxic with one dose - meaning you have to take more than one dose for toxicity to take effect.
Explanation:
Help! “Name 2 elements that can form the same type of ion as calcium. Explain”
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.
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
Answer:
particles
Explanation:
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Answer:
Explanation:
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photosynthesis is chemical change that happens in the plant what substance within the plant allows light energy to be captured
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).
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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Answer:
c
Explanation:
Answer:
C. electrons. They also have a charge of -1
How many moles are in 5.5 x 10-23 molecules of H2O
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
Regardless of how much mass they have, all stars will become a ______?
Answer:
high mass- a red supergiant
low mass-red giant
Explanation:
All stars, regardless of their size, eventually run out of fuel and collapse due to gravity
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
the structure and bonding of gold?
Answer:
metallic bonding
Explanation:
since it is a metal gold forms metalllic bonding.
Answer:
metalic bonding
Explanation:
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
Answer:H2O = H2 + O
Explanation:
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.
2H20 → 2H2 + O2
Type of reaction?
Answer:
Notice how the elements splitIt is a decomposition reaction I do exams and quizzes if ur interestedChemistry question on enthalpy HELP!!!!
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
4 points
9. Name the scientists that played a major role in the development of cell theory. *
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 ?
Explanation:
In order to be able to answer this question, you must know the value of water's enthalpy of fusion, ΔHfus
What is the purpose of the stairstep pattern on the periodic table of the elements?
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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for an atom to be considered electrically neutral it must contain the same number of
what is the product for the synthesis reaction Na+O2
1-NaO
2-NaO2
3-Na2O
4-Na3O2
5-Na2O3
6-Na2O2
why do molecules and atoms speed up when the amount of heat increases
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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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
Answer:
22.)B. l and lll only
23.)D.sulfuric acid, magnesium, and chocolate chip cookies
and soda pop
A closed container has 5.60 x 1023 molecules of oxygen gas (O2). How many moles is that?
500.0 mL of a gas is collected at 745 K. What will the volume be at standard temperature?
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:
How does solar energy affect climate?
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
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 + .
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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Conduction does not work well in metals.
True or False
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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How many atoms of oxygen are in 75.6g of silver nitrate (AgNO3)?
Answer:
1.50x10^21 molecules O2
Explanation:
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
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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.
Answer:
uh.. How many do you want done??
Explanation:
How many significant figures are in this measurement: 1,250,500