Answer:
C gold
Explanation:
Which of the following is most likely an indication of a chemical change?
A. A loud sound when an MP3 player is turned on
B. A loud sound when someone claps their hands
C. A loud sound when a starter's pistol is fired at a race
D. A loud sound when a large object falls to the ground
Hello there!
Question: Which of the following is most likely an indication of a chemical change?
Answer Choices:
A. A loud sound when an MP3 player is turned on.
B. A loud sound when someone claps their hands.
C. A loud sound when a starter's pistol is fired at a race.
D. A loud sound when a large object falls to the ground.
Correct Answer:
C. A loud sound when a starter's pistol is fired at a race.
Reasons:
A would not be correct since an MP3 player is a mechanical object and does not mix any substances that create a reaction.
B would not be correct since clapping hands causes a loud sound due to two forces slamming together and causes a disturbance in the air.
D would not be correct since a large object falling to the ground does not indicate any chemical reactions or changes since its merely the result of a mass hitting another mass.
C would be correct since the gunpowder mixes with other substances inside the pistol's chamber and causes and explosion, and explosions are part of a chemical reaction indicators.
What is the percent of iron (Fe) in 325g of FeCl3
Answer:
Element Symbol Mass Percent
Chlorine Cl 65.571%
Iron Fe 34.429%
Explanation:
6) Find the pH of the following solutions:
a) 0.00010 M HClO4
b) 2.35 x 10-3 M HI
c) 4.678 x 10-5 M HNO3
d) 0.0000877 M HCl
e) 0.00020 M HF
f) 0.0000061 M H3O+
g) 4.3 x 10-3 M NaOH (This is a base! Remember you will be finding pOH first!)
h) 6.7 x 10-9 M KOH (This is a base! Remember you will be finding pOH first!)
i) 0.00044 M HCl
j) C
Answer:
pH is the negative logarithm of hydrogen (oxonium) ion concentration of aqueous solutions.
Explanation:
Recall that pH is defined as the negative logarithm of hydrogen ion concentration. We are going to apply that definition here.
a) 0.00010 M HClO4
pH= -log[0.00010]
pH= 4
b) 2.35 x 10-3 M HI
pH= -log[2.35 x 10-3 ]
pH= 2.63
c) 4.678 x 10-5 M HNO3
pH= -log[4.678 x 10-5]
pH= 4.3
d) 0.0000877 M HCl
pH=-log[0.0000877]
pH= 4.1
e) 0.00020 M HF
pH= -log[0.00020]
pH= 3.7
f) 0.0000061 M H3O+
pH= -log[0.0000061]
pH= 5.2
g) 4.3 x 10-3 M NaOH
pOH= -log[OH^-]
pOH= -log[ 4.3 x 10-3 ]
pOH= 2.4
But
pH + pOH =14
Therefore
pH= 14-pOH
pH= 14 -2.4
pH= 11.6
h) 6.7×10^-9 M KOH
pOH= -log[OH^-]
pOH= -log[ 6.7 x 10-9 ]
pOH= 8.2
But
pH + pOH =14
Therefore
pH= 14-pOH
pH= 14 -8.2
pH=5.8
I) 0.00044M HCl
pH= -log[0.00044]
pH= 3.4
Answer: A. 4 B. 2.6 C. 4.3 D. 4.1 E. 3.7 F. 5.8 G. 11.6 H. 5.8 I. 3.4
Explanation:
A. 0.00010 M HClO4
pH = -log [1.0 x 10^-4]
= 4 - log 1 = 4
B. 2.5 x 10^-3 M HI
pH = -log [2.5 x 10^-3]
= 3 - log 2.5
= 3 - 0.398 = 2.6
C. 4.678 x 10^M HNO3
pH = -log [4.678 x 10^-5]
= 5 - 0.7 = 4 .3
D. 0.0000877M HCL
pH = - log [8.77 x 10^-5]
= 5 -0.943 = 4.057 =4.1
E. 0.00020M HF
pH = -log [2.0 x10^-4]
= 4 - 0.301 = 3.7
F. 0.0000061M H3O+
pH = - log [ 6.1 x 10^-6]
= 6 -0.785 = 5.2
G. 4.3 x 10^-3 M NaOH
Finding pOH first , we have
pOH = - log [4.3 x 10-3]
= 3 - 0.633 = 2.4
pH + pOH = 14
pH = 14 - 2.4 = 11.6
H. 6.7 x 10^-9 M KOH
Finding pOH, we have,
pOH = - log [6.7 x 10^-9]
= 9 - 0.826 = 8.17 = 8.2
pH + pOH = 14
pH = 14 - 8.2 = 5.8
I. 0.00044 M HCl
pH = -log [ 4.4 x 10^-4]
= 4 - 0.64 = 3.36 = 3.4
what environmental issues occur in our community
Answer:Deforestation, Pollution, Water pollution, Overpopulation, Public health, Global warming, Disposal of wastes
Explanation:
Which best describes a force?
a vector with magnitude and direction
a vector with speed and strength
a vector with direction only
a vector with strength only
Mark this and retum
Save and Exit
Next
Submit
Answer:
a vector with speed and strenght
Explanation:
Answer:
Explanation:
A
Compare and contrast the goals of the General Mining Law of 1872 and the proposed Hardrock Mining and Reclamation Act of 2009.
Answer: seen below
Explanation:
the goals of the General Mining Law of 1872 state that, anyone can stake mining claims on federal land, and they pay no more than $5 an acre while they keep 100% of profits with little to no environmental provisions.
Taxpayers pay for clean up of sites.
While the goals of proposed Hardrock Mining and Reclamation Act of 2009 includes, Increasing acreage of lands off limits to exploration and development. Protecting of National Parks and National Monuments is essential. Giving land managers the ability to balance mineral activities with other uses of public land. Giving state, local and tribal government the ability to put lands off limits to mining although, this bill never became law.
Determine the mass of oxygen produced in the decomposition of 25.0 g of potassium
chlorate, which would also yield the formation of potassium chloride. Show steps please!
Answer:
9.80g of O2.
Explanation:
Step 1:
The balanced equation for the reaction. This is given below:
2KClO3 —> 2KCl + 3O2
Step 2:
Determination of the mass of KClO3 that decomposed and the mass of O2 produced from the balanced equation. This is illustrated below:
Molar Mass of KClO3 = 39 + 35.5 + (16x3) = 122.5g/mol
Mass of KClO3 from the balanced equation = 2 x 122.5 = 245g
Molar Mass of O2 = 16x2 = 32g/mol
Mass of O2 from the balanced equation = 3 x 32 = 96g.
From the balanced equation above, 245g of KClO3 decomposed to produce 96g of O2.
Step 3:
Determination of the mass of O2 produced in the decomposition of 25.0g of KClO3. This is illustrated below:
From the balanced equation above, 245g of KClO3 decomposed to produce 96g of O2.
Therefore, 25g of KClO3 will decompose to produce = (25x96)/245 =
9.80g of O2.
Therefore, 9.80g of O2 is produced from the decomposition of 25g of KClO3.
Help! Drag and drop the answer into the box to match each method of how to separate solutions to its description.
Answer:
1) D 2) A 3) C
Explanation:
How long does it take light from the sun to reach Earth?
8 minutes 20 seconds
it's instant
7 years 20 days
about an hour
Answer:
8 minutes and 20 seconds
Why does BROMINE have a smaller atomic radius then SCANDRUM
Answer:
So while Bromine has 15 more electrons, they're occupying about the same space as Calcium's and since Bromine's nucleus has a stronger positive charge, it pulls that shell closer in, making Bromine overall smaller.
Explanation:
What volume of 1.25 M lithium hydroxide LiOH is needed to neutralize 445 ml of 0.550 M phosphoric acid (H₃PO₄ )?
Answer:
0.587 litres (3 s.f.)
Explanation:
Please see attached picture for full solution.
what temperature in kelvin does 21 of sulfur dioxide occupy if there are 2.5 mol of it at 1.75 atm?
Answer: 179 K
Explanation:
According to ideal gas equation:
[tex]PV=nRT[/tex]
P = pressure of gas = 1.75 atm
V = Volume of gas = 21 L
n = number of moles = 2.5
R = gas constant =[tex]0.0821Latm/Kmol[/tex]
T = temperature in Kelvin = ?
[tex]T=\frac{PV}{nR}[/tex]
Putting the values , we get :
[tex]T=\frac{1.75atm\times 21L}{2.5\times 0.0820 L atm/K mol}=179K[/tex]
Thus temperature in kelvin is 179 for 21 L of sulfur dioxide occupy if there are 2.5 mol of it at 1.75 atm
The taxonomic classification system contains three Domains . List all 3 Domains: (Hint: last 3 slides of the PDF Power Point will all give the answer
Answer:
Archaea, Bacteria, and Eukarya.
Explanation:
hope this helped
PLEASE HELP ME
Which statement is true about HCl? (15 points)
Select one:
a. It is a salt because it increases the concentration of metallic ions.
B. It is a salt because it is formed by the reaction of an acid and a base.
C. It is an acid because it increases the concentration of hydroxyl ions. D. It is an acid because it increases the concentration of hydrogen ions.
Answer:
A i think idk sry
Explanation:
Answer: D
Explanation: It is an acid because it increases the concentration of hydrogen ions
Someone please help me rephrase this or make it shorter :
When light shines on an object it is reflected, absorbed or transmitted through the objects material and the frequency (color) of the light.
Answer:
When light shines on an object it is either reflected, absorbed, or transmitted through the object to produce a frequency (color).
Explanation:
When light shines on an object it is either it is reflected, absorbed or transmitted through the objects material and produce light of some frequency or color.
What is reflection?Reflection is the process in which an incident light ray on a transparent material returns back in the straight direction which make the material gleaming.
Absorption is the process of absorbing a fraction of the incident light. It depends on the nature of the material. Transmission is the process of penetrating of light through a material and returns backs through the other end.
All these three process does no occur together for a material. Either one will be taken place when light is hit on the material and it reflects or transmits it produce a light of certain frequency.
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5 Points
How have scientists been able to determine the composition of Earth's
layers?
A. By studying the magnetic fields of various planets and moons
B. By looking at how seismic waves change speeds as they travel
through Earth
C. By looking at how X-rays affect the planet
D. By studying layers of other planets and moons
CUIDAIT
Answer:
B
Explanation:
By looking at how seismic waves change speeds as they travel
through Earth
Answer:
b.
Explanation:
Suppose that a solution is tested for NO2 ion by adding 3M H2SO4 and heating, repeating this process until no further reaction occurs. This solution
is then analyzed for NO3 ion by adding FeSO4 solution and more H2SO4, heating the test tube and its contents. The NO3 ion reaction is positive. In this case, is it accurate to state that NO3 ion was present in the original solution? Briefly explain. Write appropriate equations to support your answer.
Answer:
The correct equation will be "[Fe(H2O)5]²⁺ + NO → Fe(H2O)5NO]²+ (brown ring) ".
Explanation:
For NO₂, the addition of H₂SO₄ forms HNO₂ comprising NO gas as well as HNO₂, the equation will be:
⇒ NO₂⁻ + 2H⁺ → HNO2
⇒ HNO₂ + H₂O + H⁺ → HNO₃ + NO
For NO₃⁻,
NO₃⁻, Fe₂+ oxidized to Fe₃ + then releases NO gas in the existence of H₂SO₄
⇒ 3Fe₂⁺ + 4H⁺ + NO₃⁻ → 3Fe₃⁺ + NO + 2H₂O
Brown ring forming establishes NO3- presence in the initial test sample,
⇒ [Fe(H2O)5]²⁺ + NO → Fe(H2O)5NO]²+ (brown ring)
Many functions of the nervous system require you to think about them to make them happen and are called ____ ?
What is the molariity of a 50.0 mL aqueous solution containing 10.0 grams of acetic acid, CH3COOH
Answer:
Molarity is 1.25
Earth would fly off into space in a straight line if the ______________________________
between Earth and the Sun ended.
Answer:
Gravity
Earth would fly off into space in a straight line if the gravity
between Earth and the Sun ended
Explanation:
The Earth's orbit is made through gravity and inertia. If gravity between the Sun and Earth had ended, inertia would make the Earth travel in a straight line because there is no gravity to pull it towards the sun and keep it in motion.
Which process was responsible for producing gases in the early atmosphere?
Answer: The early atmosphere
Explanation: Its early atmosphere was probably formed from the gases given out by volcanoes. It is believed that there was intense volcanic activity for the first billion years of the Earth's existence. The early atmosphere was probably mostly carbon dioxide, with little or no oxygen.
Why would the Linnaeus system not stay the same? Explain in your own words.
Answer:
The Linnaeus system of classification will always stay the same. o Fact: Linnaeus system will always stay the same exact way.so therefore it will stay the sam infact it will keep going.
Explanation:
Evidence shows that traits going from species,genus,family,order,class,phymisnes,and then kingdom.
0.00056 kg = in metric conversion
Answer:
0.56
Explanation:
Answer:
0.56
Explanation:
in the metric stair case there is 3 space between g and kg, since you are going down you move the decimal 3x to the right.
What process does the equation represent?
U92235+n01→T52137e+Z4097r+2n01
a.) alpha emission
b.)fusion
c.) nucleosynthesis
d.) fission
The answer is d.) fission :)
The equation represents the fission process. In fission the energy is gained by dividing atoms.
Alpha emissionIn this process, the parent isotope emits 2 neutron and 2 proton.
The equation is represented as:
[tex]^{A}_{Z} X \rightarrow ^{A - 4}_{Z - 2} Y + {^{4}_{2}} He[/tex]
FusionIt is the combination of two or more smaller atoms to create a larger one. Fusion require high temperature and pressure (conditions).
The equation is represented as:
[tex]2{^{2}_{1}} H \rightarrow ^{3}_{2} He + ^{1}_{0} n[/tex]
NucleosynthesisThe process in which new atomic nuclei created from pre-existing neutron, proton and nuclei is called Nucleosynthesis.
Fission
It is a heavy nucleus which splits up in to form two lighter nuclei.
The equation is represented as:
[tex]^{235}_{92}U + ^{1}_{0} n \rightarrow ^{141}_{56} Ba + ^{92}_{36} Kr + 3 ^{1}_{0} n[/tex]
So the given equation in question satisfies this equation. So fission represent the process.
Thus, from above conclusion we can say that the equation represent fission process. So option D is correct answer.
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When 10 moles of O₂ reacts with 1.4 moles of C₁₀H₈ what is the limiting reactant? *
Answer:
O2 is the limiting reactant.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
2C10H18 + 29O2 —> 20CO2 + 18H2O
The limiting reactant can be obtained as follow:
From the balanced equation above,
2 moles of C10H18 reacted with 29 moles of O2.
Therefore, 1.4 mole of C10H18 will react with = (1.4 x 29)/2 = 20.3 moles of O2.
From the above calculation, we can see that it will take a higher amount of O2 i.e 20.3 moles than what was given i.e 10 moles to react completely with 1.4 mole of C10H18. Therefore, O2 is the limiting reactant and C10H18 is the excess reactant.
Which freshwater ecosystem is least productive?
O A. Stream
B. Bog
C. Marsh
D. Swamp
SUBMIT
An oxidation reaction requires which of the following for most common
Answer: Oxygen
Explanation:most common fires require oxygen for a fire to start. With out oxygen the fire will go out.
An oxidation reaction typically requires an oxidizing agent, which is a substance which accepts electrons and causes the oxidation of another substance.
What is an Oxidation reaction?Any chemical reaction in which electrons are transferred from one substance to another is called an oxidation reaction. The process of losing electrons is called oxidation, and the process of gaining electrons is called reduction. In other words, electrons are lost during oxidation while they are gained during reduction.
Redox reactions, which always involve these two processes, are called. Oxidation processes can lead to a number of chemical changes, including the formation of new chemical bonds, the release of energy, or the synthesis of new compounds. Oxidation reactions are involved in many natural processes, such as burning, rusting, and cellular respiration.
Therefore, an oxidation reaction typically requires an oxidizing agent, which is a substance which accepts electrons and causes the oxidation of another substance.
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What is the total mass of solute in 1000 g of a solution having a concentration of 5 ppm
It's 500 pounds worth of rpm and solute when put together to form a compound of space and time to warp quantum matter to the point of no existence for big bang reopening of time and super warp of neutral electronic atoms with a power of 4 to 5 in ratio of micrometers squared to the power of 10
Check all reasons why a syringe was a good
choice of tool in this experiment.
It has volume markings that can be read.
It will not easily leak gas.
The volume can change.
DONE
Answer : All Choices And Then The First Two
A syringe was a good choice of tool in this experiment.
It has volume markings that can be read.It will not easily leak gas.A syringe is a simple reciprocating pump consisting of a plunger (though in modern syringes, it is actually a piston) that fits tightly within a cylindrical tube called a barrel
How is syringe made?To manufacture plastic syringes, the machinery required will be injection moulding machines, set of Multi cavity moulds and sterilization chamber. Polypropylene granules are fed into an injection-moulding machine, where they are plasticized and then injected into a Multi cavity mould.
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What’s the oxidation number for S2O3
Answer:
+4 +3(-2) = -2
Explanation: