Answer:
a solution color becoming less intense due to dilution- is not an evidence of a chemical reaction
bubbles (gas formation) - evidence of a chemical reaction
explosion or fire - evidence of a chemical reaction
changes in color- evidence of a chemical reaction
precipitation- evidence of a chemical reaction
changes in temperature - evidence of a chemical reaction
a solid liquifying - is not an evidence of a chemical reaction
solution colors mixing - is not an evidence of a chemical reaction
Explanation:
A chemical change is not easily reversible and yields new substances. It is often accompanied by a loss or gain of heat.
In the answer section, i have shown some evidences that lead us to conclude that a chemical reaction has taken place. The occurrence of a chemical change often goes with the formation of new substances as earlier stated and any of these signs may accompany the process.
For instance, when a metal is dropped in dilute acid solution, bubble of hydrogen gas indicates that a chemical reaction has taken place.
Measure that affects the thermal energy of matter but not it's temperature.
Answer: mass
Explanation:
Mr. Smith wanted to see if the color of light shined on a plant had an effect on the number of leaves it had. He gathered a 2
groups of the same species of plants, gave them the same amount of water, and did the test for the same amount of time.
On one group of plants he used white light. On the second group he changed the light color to red. Identify:
Independent variable:
Dependent variable:
Constants:
Control group (What would Mr. Smith use as a control group?):
Experimental group (what would Mr. Smith use as a experimental group?)
Electromagnetic waves travel because of ____
because they need a medium to travel they can travel everywhere if they got the medium
what is a difference between water and wind
Answer:
You could have looked it up, but here ya go...
Explanation:
Wind is a type of dry deposition method. If original soil is eroded and wind exists, soil particles move via wind (sometimes it is called dust transport) and finally are deposited at final destination regions/areas. However, water erosion occurs when rainfall or hail occurs.
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Sodium chloride (NaCl) is an ionic compound. We can effectively model it as sodium atoms with one electron removed next to chlorine atoms with one electron added. The attractive force between the positive and negative charges holds the crystal together. If we model the sodium and chlorine ions as point charges separated by 0.28 nm, the spacing in the crystal, what is the magnitude of the attractive force between two adjacent ions
Answer:
The attractive force between the sodium and chloride ions has a magnitude of -2.94 x 10⁻⁹ N
Explanation:
An electron is a negatively-charged particle. The charge on an electron is -1.6 x 10⁻¹⁹ C. This is also known as the fundamental unit of charge, e. A proton has the same charge as as electron but its charge is positive.
The charge on the chloride ion is negative and is due to an electron whereas the charge on the sodium ion is positive and is due to a proton.
The magnitude of the force of attraction between two charges is given by the Coulomb's law: F = Kq₁q₂/r²
where K is a constant = 9 x 10⁹ N.m₂.C⁻², q₁ = -1.6 x 10⁻¹⁹ C, q₂ = +1.6 x 10⁻¹⁹ C, r = 0.28 nm = 0.28 x 10⁻⁹ m
F = {(9 x 10⁹ N.m₂.C⁻²) (-1.6 x 10⁻¹⁹ C) (+1.6 x 10⁻¹⁹ C)} / (0.28 x 10⁻⁹ m)²
F = -2.94 x 10⁻⁹ N
Therefore, the attractive force between the sodium and chloride ions has a magnitude of -2.94 x 10⁻⁹ N
How many liters are in 7.41 x 1026 atoms of helium (He) at STP?
Answer:
Explanation: Avogadro number,N, = 6.02214076*10^23per mole —> 22.71L
—>( 7.41*10^26/N)*22.71 = 22.79*10^3 = 22,790L
air is trasferred from 75 L tank where the pressure is 125 psi and the temperature is 288 K to a tire with a volume. of 6.1 L and a pressure of 25 psi. what is the new temperature ?
Answer:
4.7K
Explanation:
Given parameters:
Initial volume = 75L
Initial pressure = 125psi
to atm gives 8.5atm
Initial temperature = 288K
New volume = 6.1L
New pressure = 25psi
to atm gives 1.7atm
Unknown:
New temperature = ?
Solution:
To solve this problem, we use the combined gas law which is given below:
[tex]\frac{P1 V1}{T1}[/tex] = [tex]\frac{P2 V2}{T2}[/tex]
P, V and T are pressure, volume and temperature
1 and 2 are initial and new states
[tex]\frac{8.5 x 75}{288}[/tex] = [tex]\frac{1.7 x 6.1}{T2}[/tex]
T2 = 4.7K
Twelve grams of gas occupies 14.5 liters at a pressure of 52.0cm Hg. What is the volume when the pressure has increased to 85.0cm Hg?
Answer:
8.87 L.
Explanation:
From the question given above, the following data were obtained:
Mass (m) of gas = 12 g
Initial volume (V₁) = 14.5 L
Initial pressure (P₁) = 52 cmHg
Final pressure (P₂) = 85 cmHg
Final volume (V₂) =?
The final volume of the gas can be obtained by using the Boyle's Las equation as illustrated below:
P₁V₁ = P₂V₂
52 × 14.5 = 85 × V₂
754 = 85 × V₂
Divide both side by 85
V₂ = 754 / 85
V₂ = 8.87 L
Thus the volume of the gas will be 8.87 L
(9) How many moles of oleum in 1780. g of oleum? - Write an equation to summarize the process.
Answer:
1. 10moles
2. Find the summarized equation below
Explanation:
Mole = mass ÷ molar mass
Molar mass of oleum (H2S2O7) = 1(2) + 32(2) + 16(7)
= 2 + 64 + 112
= 178g/mol
According to the information provided, the mass of oleum is 1780g, hence, the number of moles in it is:
Mole = 1780/178
Mole = 10moles
2. The summarized equation of the contact process is:
1) S + O2 → SO2
2) 2SO2 + O2 → 2SO3
3) SO3 + H2SO4 (conc. sulfuric acid) → H2S2O7
4) H2S2O7 + H2O → 2H2SO4 (dilute sulfuric acid)
The half life of iodine-125 is 60 days. What fraction of iodine-125 nuclides would be left after 360 days?
Explanation:
The half-life is the time taken for a radioactive substance to decay to half of its original composition.
Let us assume that the original amount is x atoms;
Half - life = 60days
Days Composition Half-life number
0 x 0
60 x/2 1
120 x/4 2
180 x/8 3
240 x/16 4
300 x/32 5
360 x/64 6
The fraction that would be left after 360 days will be [tex]\frac{1}{64}[/tex]
___________ changes affect the nuclei (nucleus) of an atom, which produces new elements. (A Nuclear (B Chemical (C Physical
Answer:
A
Explanation:
matter can undergo chemical reactions and nuclear reactions. which properly is conserved in nuclear reactions?
Answer:change in number of atoms
Explanation:AP3X
what is the thing that you change in an experiment so that you can study the result of the change its called?
The table below shows properties of two compounds at standard pressure. Which statement classifies the two compounds? 1)Both compounds are ionic, 2)Both compounds are molecular, 3) Compound 1 is ionic, and compound 2 is molecular, 4)Compound 1 is molecular, and compound is ionic
Answer:
3) Compound 1 is ionic, and compound 2 is molecular
Explanation:
Compound-1 is an ionic compound while Compound-2 is a molecular compound. Option 3 is correct.
Ionic Compound:
They are formed when an atom donates its electron to another atom. This results in one positive and one negative ion.
Hence, it is a very strong bond. These compounds have a very high melting and boiling point. They are very good electric conductors in the aqueous solution.
For example- NaCl.
Molecular compounds:
They are compounds that are made up of discrete molecular units. For example- [tex]\bold {H_2O}[/tex]
They have very weak intermolecular bonds hence have low boiling and melting point and do not conduct electricity.
SInce Compound-1 has higher MP and BP and Compound-2 has low melting and boiling point.
Therefore, Compound-1 is an ionic compound while Compound-2 is a molecular compound.
To know more about Ionic Compound:
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what is the magnification of the eye piece on the microscope?
Answer:
The magnification is 10x
Explanation:
Answer: The magnification of the eyepiece on the microscope is the lens at the top of the microscope that the user looks through. This lens most commonly magnifies a sample by 10x
Explanation: The eyepiece magnifies the primary image produced by the objective; the eye can then use the full resolution capability of the objective. The microscope produces a virtual image of the specimen at the point of the distinct vision.
How many grams of water are produced when 37.7 g of hydrogen peroxide (H2O2) decomposes into oxygen gas and water?
Answer:
Mass of water produced = 19.8 g
Explanation:
Given data:
Mass of hydrogen peroxide = 37.7 g
Mass of water produced = ?
Solution:
Chemical equation:
2H₂O₂ → 2H₂O + O₂
Number of moles of H₂O₂:
Number of moles = mass/molar mass
Number of moles = 37.7 g/ 34 g/mol
Number of moles = 1.1 mol
Now we will compare the moles of H₂O₂ and H₂O from balance chemical equation in order to determine the moles of water formed.
H₂O₂ ; H₂O
2 : 2
1.1 : 1.1
Mass of water formed:
Mass = number of moles × molar mass
Mass = 1.1 mol × 18 g/mol
Mass = 19.8 g
How many moles are in 1.23 x 1024 molecules of oxygen gas.
Answer:
2.04moles
Explanation:
Given parameters:
Number of molecules = 1.23 x 10²⁴molecules
Unknown:
Number of moles of oxygen gas = ?
Solution:
To solve this problem;
6.02 x 10²³ molecules makes up 1 mole of any substance
1.23 x 10²⁴molecules will make up [tex]\frac{1.23 x 10^{24} }{6.02 x 10^{23} }[/tex] = 2.04moles
6.02 x 10²³ molecules makes up 1 mole of any substance
1.23 x 10²⁴molecules will make up = 2.04moles
1. What are the two effects of the continental plate/continental plate convergent boundary?
2. Where can you find an example of this type of divergent boundary? Which country, continent or ocean?
Answer
oh you again?
Explanation:
according to the bohr model of an atom, what happens when an electron moves from the second energy level to the third energy level and then back to the second energy level?
Answer:
when the atom moves to the third energy level, its energy increases. However, when it goes back to the second energy level its overall energy decreases.
Explanation:
the smallest (or innermost) energy level has the least amount of energy and the largest (or outer most) level needs the most amount of energy. In order for the electron to move from one level to the other, it would need to match the energy of that level.
Propane is what type of matter?
Element
Compound
Homogeneous mixture
Heterogeneous mixture
Which is a characteristic of a solution?
Its particles scatter light.
Its particles are evenly distributed.
Its particles settle out.
It has large suspended particles.
Answer:
Its particles are evenly distributed.
Explanation:
Solutions are homogenous mixtures of solutes and solvents. In a solution the solute particles are evenly distributed in the solvent.
Here are some characteristics of solutions:
The size of the particles is small The particles do not settle on standingThe particles pass through ordinary filter papersThe particles pass through permeable membranesThe particles are not visible with microscope or the naked eyes. They are clear and may have a color.A characteristic of a solution is that its particles are evenly distributed.
What are solutions?A characteristic of a solution is that its particles are evenly distributed. In a solution, the solute (substance being dissolved) is uniformly distributed and mixed with the solvent (the substance doing the dissolving) at the molecular or ionic level.
The particles of the solute become thoroughly dispersed and do not settle out over time. Solutions are generally clear and do not scatter light, unlike suspensions or colloids which may exhibit light scattering due to the presence of larger particles.
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All moving objects have kinetic energy. True False
Answer:
true
.......................
Answer: You're Welcome!
Oh, It's False - Kinetic energy depends upon the speed of the object; potential energy depends upon the position of the object.
A chemist adds 600.0mL of a 0.444/gL calcium sulfate CaSO4 solution to a flask. Calculate the mass in grams of calcium sulfate the chemist has added to the flask. Be sure your answer has the correct number of significant digits.
Answer:
0.266 grams of calcium sulfate
Explanation:
We can calculate the mass of calcium sulfate added using the given volume and concentration of the solution:
First we convert 600.0 mL to L ⇒ 600.0 mL equals 0.6000 L (600 ÷ 1000).
0.444 g/L * 0.6000 L = 0.266 g
Thus the answer is 0.266 grams of calcium sulfate.
US
What is the percent of H in
NH3?
(H = 1.008 amu, N = 14.01 amu)
[?]%
Answer:
17.6
Explanation:
Answer is explained above
The average atomic mass for germanium is 72.631 amu. If germanium occurred as a mixture of the two isotopes below, what would be the percent abundance of 73Ge in the mixture?
mass of 70Ge = 69.924 amu
mass of 73Ge = 72.923 amu
Percent abundance of 73Ge in nature = ________ %
Answer:
dora needs help
Explanation:
Answer:
...........................
You want to determine the concentration of a phosphoric acid (H3PO4) solution using a standardized 0.0995 M NaOH solution. 10.00 mL of the H3PO4 solution needed to be titrated with 22.85 mL of the standardized 0.0995M NaOH solution to reach the equivalence point. What is the concentration of the H3PO4 solution
Answer:
Explanation:
H₃PO₄ + 3NaOH = Na₃PO₄ + 3 H₂O.
1 mole 3 mole
22.85 mL of the standardized 0.0995M NaOH solution will contain
.0995 x .02285 moles of NaOH
= 22.7357 x 10⁻⁴ moles of NaOH
3 moles of NaOH reacts with 1 mole of H₃PO₄
22.7357 x 10⁻⁴ moles of NaOH reacts with 1 x 22.7357 x 10⁻⁴ / 3 mole of H₃PO₄
= 7.5785 x 10⁻⁴ moles of H₃PO₄
7.5785 x 10⁻⁴ moles of H₃PO₄ is contained in 10 mL or 10⁻² L
molarity of H₃PO₄ solution = 7.5785 x 10⁻⁴ / 10⁻²
= 7.58 x 10⁻² M
= .0758 M .
Is Gold (Au) soluble?
Answer:
yes
Explanation:
What is the measure of the amount of dissolved salts in ocean water?
Answer:
Salinity
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Explanation:
What is Sr(NO3)2 + ZN ?
Answer:
strontium nitrate
Explanation:
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How do the percent compositions for C3H6 and C4H7 compare?
A. They are the same
B. C4H8 has a higher percentage of carbon than C3H6.
C. C4H8 has a higher percentage of hydrogen than C3H6.
D. none of the above
A. They are the same
Further explanationGiven
C3H6 and C4H8
Required
The percent compositions
Solution
C₃H₆(MW = 42 g/mol)%C = 3.12/42 x 100% = 85.71%
%H = 6.1/42 x 1005 = 14.29%
C₄H₈(MW=56 g/mol)
%C = 4.12/56 x 100% = 85.71%
%H = 8.1/56 x 100%=14.29%
So they are the same, because mol ratio of C and H in both compounds is the same, 1: 2