Answer:
66.7%
Explanation:
The reaction for the titration of the excess ferrous ion is:
5Fe⁺² + MnO₄⁻ + 8H⁺ → 5Fe³⁺ + Mn²⁺ + 4H₂OWe calculate the moles of Fe⁺² from the used moles of KMnO₄:
0.02 M * 15.0 mL = 0.30 mmol KMnO₄0.3 mmol KMnO₄ * [tex]\frac{5mmolFe^{+2}}{1mmolKMnO_4}[/tex] = 1.5 mmol Fe⁺²Then we substract those 0.30 mmol from the original amount used:
0.1 M * 50.0 mL = 5.0 mmol Fe⁺²5.0 - 1.5 = 3.5 mmol Fe⁺²The reaction between ferrous ammonium sulfate and MnO₂ is:
2Fe⁺² + MnO₂ + 4H⁺ → 2Fe³⁺ + Mn²⁺ + 2H₂OSo we convert those 3.5 mmol Fe⁺² that were used in this reaction to MnO₂ moles:
3.5 mmol Fe⁺² * [tex]\frac{1mmolMnO_2}{2mmolFe^{+2}}[/tex]= 1.75 mmol MnO₂Then we convert MnO₂ to Mn₃O₄, using the reaction:
3MnO₂ → Mn₃O₄ + O₂1.75 mmol MnO₂ * [tex]\frac{1mmolMn_3O_4}{3mmolMnO_2}[/tex] = 0.583 mmol Mn₃O₄Finally we convert Mn₃O₄ moles to grams:
0.583 mmol Mn₃O₄ * 228.82 mg/mmol = 133.40 mg Mn₃O₄And calculate the percent
0.2 g = 200 mg133.40 / 200 * 100% = 66.7%How much water must be added to 424 mL of 0.189 M HCl to produce a 0.140 M solution?
Answer:
Volume of water added = 148.4 mL
Explanation:
Given data:
Initial volume = 424 mL
Initial molarity = 0.189 M
Final molarity = 0.140 M
Volume of water added = ?
Solution:
Formula:
M₁V₁ = M₂V₂
0.189 M×424 mL = 0.140 M×V₂
V₂ = 0.189 M×424 mL /0.140 M
V₂ = 80.136 M.mL / 0.140 M
V₂ = 572.4 mL
Final volume of solution is 572.4 mL.
Volume of water added = Final volume - initial volume
Volume of water added = 572.4 mL - 424 mL
Volume of water added = 148.4 mL
Explain your thoughts on whether or not using solely IR is a good method to make positive IDs of chemicals.
Answer:
No, IR should not soely be used to identify molecules
Explanation:
IR is a method that identifies the functional groups in a molecule by deducing the frequency of stretching and vibration of bonds. Each peculiar type of bond has a frequency for the vibration of each bond represented on the IR spectrum.
However, one method is never enough to identify a compound. A combination of methods must always be used to clear up ambiguities arising from overlapping IR frequencies. Also, interpretation of the nuanced peaks of the fingerprint region in IR spectra is quite challenging and only gives a fair idea of the functional groups present in the compound.
Therefore other methods such as NMR, UV-VISIBLE etc should also be involved in the identification of compounds.
who established the two important laws of chemical combination combination state them
Answer:
Antoine Lavoisier
1) Law of Conservation of Mass
French chemist, Antoine Lavoisier in 1789, studied this law. This law states that “In all physical and chemical changes, the total mass of the reactants is equal to that of the products” or “Mass can neither be created nor destroyed.”
Determine the density of CO2 gas at STP
Answer:
the density of CO2 gas at STP is 1.96 g/l.
PLS HELP 35 POINTS I WILL GIVE BRAINEST
Answer:
Just count all the different elements like what elemets are in there and you have to identify the number of elemenst
Explanation:
for example H20 and a chemical for example thats two so you identofy which elelments are in there doesnt matter if thered multiple of it all its asking is what id the number of elemts there meaning like one or 2 mayne six different elements
Which statement best describes why a chemical property change is different from a physical change?
A. A chemical change results in a different state of matter; and a physical change results in a new substance being formed.
B. A chemical change results in a new substance being formed; whereas, a physical change will result in a different state of matter.
C. A chemical change is used by scientists to create new substances, and a physical change happens naturally.
D. A chemical change is used to identify characteristics of a substance, and a physical change identifies the behavior of a substance when in a reaction.
Answer:
B
Explanation:
a chemical change is making a new substance and physical change with a result in a different state of matter:)
2. Enumerate four Reactive Oxygen Species (ROS)
Answer:
Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen.
At the Sparta Fault in Greece, the hanging wall is below the footwall. This type of fault is called a .
Answer:
1 a
Explanation:
how many moles of ethanol C2H6O, are in a 10.0g sample
Answer: 0.217 mol
Explanation:
To find the amount of moles in a 10 g sample, we need the molar mass of ethanol.
Molar Mass: 46.07 g/mol
Now that we have the molar mass, we can find moles.
[tex]10.0 g*\frac{1mol}{46.07g}=0.217 mol[/tex]
We know that there are 0.217 mol in a 10.0 gram sample.
1. How many Chromium atoms are found in 25.8 milligrams of Chromium?
Answer: 51.9961 g/mol, don't know if it helps :)
Explanation:
Answer:
Chromium is a steel-gray, lustrous, hard metal that takes a high polish, is fusible with difficulty, and is resistant to corrosion and tarnishing.
The most common oxidation states of chromium are +2, +3, and +6, with +3 being the most stable. +4 and +5 are relatively rare. Chromium compounds of oxidation state 6 are powerful oxidants.ion:
Match Term Definition
Pure substance A) Liquid homogeneous mixture in which the solute is distributed evenly within the solvent
Heterogeneous B) Mixture that has its different components mixed evenly within the substance
Homogeneous C) Mixture that has its different components mixed unevenly within the substance
Solution D) Consists of a single element or type of compound
Answer:
b
Explanation:
this should help
Submit Test
Question 10 of 12- POS
GR8 Sci U03 USA FY21 Question: 1-10
Hannah added a silvery white metal to a beaker of cold water and noticed that gas bubbles were given off and a different substance formed. When she repeated the activity with hot water she noticed the gas bubbles were
released much more rapidly. Which statement best explains why the reaction occurred faster in hot water?
M
The correct answer is Hot water increases the collision rate of molecules, causing the reaction to occur faster.
Explanation:
Temperature is directly related to the kinetic energy or movement of molecules in a substance. In this context, a higher temperature leads to more kinetic energy or more collision between molecules. At the same time, a chemical reaction involves molecules of two or more substances colliding and creating bonds to form new substances. This implies an increase in temperature means molecules colliding faster, new substances forming in a shorter time, and therefore a faster chemical reaction. According to this, the first answer is correct.
How does the density and distribution of your “stars” change as the balloon expands?
Answer:
The Universe is constantly expanding and as it expands the stars and objects in space move farther apart, just like the points on the balloon when air is blown into it. Density and distribution of "stars" as the balloon expands because when volume increases the density will increase.
Hope this Helps
2. Molecular solutions do not conduct electricity because they contain: *
(1 Point)
The ions are able to move freely from one place to another. So that they conduct electricity. But the molecular solutions does not electricity.
What is a molecular solution?The molecular solution is composed of molecules and consists of non - metallic atoms. These atoms are held together by the covalent bonds. The flow of charged particles is responsible for the conduction of electricity. If there is no flow of electrons or ions then there will be no electricity.
In the molecular solutions, the molecules present are not dissociated into respective ions. Since the molecules are not converted into the charged particles no electricity is produced.
A molecular solution is regarded as a non-electrolyte which does not contain ions. But electrolytes are dissociated into ions and thereby conducts electricity. So all electrolytes are good conductors of electricity.
Thus molecular solution does not contain ions.
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What are the starting substances (molecules) in a chemical equation called?
Answer:
A chemical reaction is the process in which atoms present in the starting substances rearrange to give new chemical combinations present in the substances formed by the reaction. These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products.
A gas sample in a balloon contains 4.0 moles of gas at a particular pressure, volume and temperature. If your balloon springs a leak and the volume decreases to 1/2 of the original amount before you can plug the leak, how many moles of gas have you lost (temperature and pressure remain the same)?
Answer:
Explanation:
When volume of gas is V , pressure is P and temperature is T , if n be number of moles of gas
PV / RT = n , R is universal gas constant .
When volume becomes .5 V , pressure P and temperature T
number of moles = Px .5 V / RT = .5 PV / RT = .5 n
Number of moles of gas becomes half .
so 4 moles becomes 2 moles
No of moles lost = 4 - 2 = 2 moles.
Sweat is made up of all EXCEPT what?
*
A.Sugar
B.Salt
C.Urea
D.Urine
0.1400 mole of sucrose, C12H22O11, contains ________ moles of C.
can you show me the formula and the correct format
Answer:
it has 12 carbon atoms and 22 hydrogen atoms and 11 oxygen atoms
Explanation:
An egg sinks in fresh water but it floats on salty water.why?
Identify at least 5 pure substance found in nature,in the supermarket, grocery storeand even at your home.use the table below to explain your answer based on appearance, separating technique, boiling and melting point.
Answer:
Explanation:
1) Pure substance: Water (found at home)
Appearance: It is homogeneous since it is a single substance that appears as liquid. Homogeneous is when the components of a substance are in a single phase
Separating technique: It's component cannot be separated by physical means
Boiling point: Water boils at 100 °C
Melting point: Water melts/freezes at 0°C
2) Pure substance: Table salt (found at home)
Appearance: It is also homogeneous as it is a single substance that is solid. Separating technique: It's component cannot be separated by physical means
Boiling point: Water boils at 1,465 °C
Melting point: Water melts/freezes at 801 °C
3) Pure substance: Butter (found at home and grocery store)
Appearance: It is homogeneous even though it contains different components
Separating technique: It's component can be separated by physical means since butter is an emulsion of fat in water. The 15% water content can be evaporated/distilled out at 100 °C
Boiling point: Butter starts boiling at about 110-120 °C
Melting point: It melts at about 37 °C
4) Pure substance: Candle (wax) (found at home and grocery store)
Appearance: It is homogeneous
Separating technique: It's component cannot be separated by physical means
Boiling point: It starts boiling around 370 °C
Melting point: It melts at about 37 °C
5) Pure substance: table sugar/sucrose (found at home, grocery stores and in supermarkets)
Appearance: It is homogeneous
Separating technique: It's component cannot be separated by physical means
Boiling point: It starts boiling around 697 °C
Melting point: It melts at about 186 °C
A pure substance is an homogeneous material, having a composition, and
properties that are consistent through out the material.
The chemical properties of a pure substance are defined, such as the
products of its reaction can be predictable.
A chemical is pure when it consist of a single type of particle such as an
element, a molecule or a compound.
The five pure substances are presented as follows;
[tex]\displaystyle\begin{tabular}{|l|l|l|l|l|}\underline{Pure \ Substances}&\underline{Appearance}&\underline{Separaing Tech}&\underline{Boiling \ Point}&\underline{Melting \ point}\\1. Diamond&Translucent \ solid&Inseparable&3550^{\circ}&4830^{\circ}\\2. Table \ salt&White\ crystals&Insepble&801^{\circ}&1413^{\circ}\\3. Water&Tran parent \ liquid&Insepble&0^{\circ}&100^{\circ}\\4. Sugar&Whilte \ crystals&Heating&Decomposes&186^{\circ}\\5. Gold&Yellowish \ metal&Inseparable& 2700^{\circ}&1064^{\circ}\end{array}[/tex]
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Convert the speed of light, 3.0 x 10^8 m/s, into mi/hr. (1610 m = 1 mi). Could you please explain step by step thank you!
Answer:
[tex]v=6.7\times 10^9\ mi/hr[/tex]
Explanation:
Given that,
The speed of light is 3×10⁸ m/s
We need to convert it into mi/hr.
Since, 1 mile = 1610 m
1 hour = 3600 s
So,
[tex]v=3\times 10^8\ \dfrac{m}{s}\\\\=3\times 10^8\ \dfrac{\dfrac{1}{1610}\ \text{miles}}{\dfrac{1}{3600}\ s}\\\\=6.7\times 10^9\ mi/hr[/tex]
So, the required speed of light is [tex]6.7\times 10^9\ mi/hr[/tex].
PLEASE HURRY WILL GIVE BRAINLEST IF ANSWERED CORRECTLY
which separation method would be most successful in separating the components of a homogeneous mixture
screening
evaporation
centrifugation
magnetic separation
Answer:
Evaporation is a technique used to separate out homogeneous mixtures where there is one or more dissolved salts.
Explanation:
Hope this helps :)
what causes convection currents in a gas or liquid?
Answer:
Convection currents are caused by a temperature difference in gases and liquids. As one area becomes warmer than another the molecules have more energy and start vibrating more vigorously thus spreading out and becoming less dense. This means that the less dense parts will become more buoyant causing them to rise.
Explanation:
Answer:
Convection currents are caused by a temperature difference in gases and liquids.
Explanation:
As one area becomes warmer than another the molecules have more energy and start vibrating more vigorously thus spreading out and becoming less dense. This means that the less dense parts will become more buoyant causing them to rise.
Calculate ΔHrxn for the following reaction:CH4(g)+4Cl2(g)→CCl4(g)+4HCl(g)Use the following reactions and given ΔH′s.C(s)+2H2(g)→CH4(g)ΔH=−74.6kJC(s)+2Cl2(g)→CCl4(g)ΔH=−95.7kJH2(g)+Cl2(g)→2HCl(g)ΔH=−184.6kJ
Answer:
ΔH= -390.3kJ
Explanation:
Using Hess's law, we can obtain ΔHrxn from the sum of related reactions.
Using:
(1) C(s) + 2H2(g) → CH4(g) ΔH=−74.6kJ
(2) C(s) + 2Cl2(g) → CCl4(g) ΔH=−95.7kJ
(3) H2(g) + Cl2(g) → 2HCl(g) ΔH=−184.6kJ
(2) - (1):
CH4(g) + C(s) + 2Cl2(g) → CCl4(g) + C(s) + 2H2(g)
CH4(g) + 2Cl2(g) → CCl4(g) + 2H2(g)
ΔH= -95.7kJ - (-74.6kJ) = -21.1kJ
This reaction + 2*(3):
2H2(g) + 2Cl2(g) + CH4(g) + 2Cl2(g) → CCl4(g) + 2H2(g) +4HCl(g)
CH4(g) + 4Cl2(g) → CCl4(g) + 4HCl(g)
ΔH= -21.1kJ + 2*-184.6kJ
ΔH= -390.3kJan electric current causes water to be transformed into hydrogen and oxygen gasses a physical change or a chemical change
What are phytoplankton and what percentage of oxygen do they produce? (ASAP)
Answer:
They are plants also known as plankton and they produce about 80-85% of the world's oxygen.
Explanation:
Cells pump definition
Answer:
Pumps also called transporters, are transmembrane proteins that actively move ions and/or solutes against a concentration or electrochemical gradient across biological membranes.
ammonia is______a base
Answer:
Ammonia is moderately a base
How are changes of state different from chemical change?
Question:
How are changes of state different from chemical change?
Answer:
Physical changes alter only the size, shape, form or matter state of a material. Water boiling, melting ice, tearing paper, freezing water and crushing a can are all examples of physical changes.
On the other hand, chemical changes are a bit different. In a chemical change, a new substance is formed.
Answer:
Chemical change happens when a substance changes they molecular structure, it often involves change in color (rusting iron), transfer of energy (copper smelting), or gas bubbling.
Changes of state is a physical change. An example is ice, it melts to create water. Water then can be freezed back to ice. Water is still H2O in both states（solid/liquid) Dissovling is another example. You can dissolve salt in water and can separate it by evaporating water and leaving the salt behind.
Explanation:
Which of the following grouping contains only representative elements?
A. Na, Co, S
B. Ni, Ga, Zn
c. AI, Mg, LÍ
D. CI, O, Cd
Answer:
C
Explanation:
Al=Aluminum
Mg=Magnesium