Scientific Approach is to identify a problem and finding solution to the problem. There are various steps in scientific approach to solve a problem,
Identify the problem
Analyze the impact
Find available solution
Evaluate different alternative solutions
Choose the best alternative
Apply the solution to the problem
Measure the results
Lets say there is a fire at some place.
There are various solution available, the fire can be slowed down by water, using fire extinguisher or sand.
The best alternative is to use fire extinguisher.
The fire is vanished after the use of fire extinguisher.
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One the first chemistry test. 12 students got As, 18 students got Bs, and 20 students got Cs.
a. What is the percentage of students received Bs.
b. What is the percentage of students who received Cs?
Express your answer to the ones place.
Answer:
A. 36 percent recieved Bs
B. 40 percent of students received Cs
Explanation:
Amount of students: 12+18+20=50
Students with Bs: (18÷50) x 100 = 36%
Students with C's: (20÷50) x100 = 40%
On the first chemistry test 12 students got A, 18 students got B, and 20 student got C. Thus the percentage of students received B is 0.36 and percentage of students received c is 0.40
What is the percentage of students received B and C?In mathematics, a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign %. A percentage is a dimension less unit and it has no unit.
In above question 12 student got A, 18 student got B, and 20 student got C.
So total number of student = 12 + 18 + 20 = 50.
Then the percentage of students received B is as follows:-
Percentage of students who got B = (student who got B/Total number of student) X 100.
=(18/50) X 100
= 36%
Now percentage of students who got C = (No of students who got C/Total students)X100
=(20/50) X 100
=40%.
Therefore,On the first chemistry test 12 students got A, 18 students got B, and 20 student got C. Thus the percentage of students received B is 0.36 and percentage of students received c is 0.40 percentage of students who got B is 36% and percentage of students who got C is 40%
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Consider the following: Li(s) + ½ I₂(g) --> LiI(s) ΔH = –292 kJ. LiI(s) has a lattice energy of –753 kJ/mol. The ionization energy of Li(g) is 520 kJ/mol, the bond energy of I₂(g) is 151 kJ/mol, and the electron affinity of I(g) is –295 kJ/mol. Use these data to determine the heat of sublimation of Li(s).
Answer:
Heat of sublimation of Li(s) = 160.5 kJ/mol
Explanation:
Given that:
[tex]\mathtt{2Li(s) + \dfrac{1}{2} I_2(g) \to 2LiI(s)}[/tex]
ΔH = –292 kJ
The heat of formation for the above reaction = –292 kJ × 2 = -584 kJ/mol
[tex]\mathtt{Li^+_{(g)} + I^-_{(g)} \to LiI_{(s)}}[/tex]
The lattice energy of LiI(s) = -753 kJ/mol
[tex]\mathtt{Li(g)\to Li^+(g) + e^- }[/tex]
The ionization energy of LiI(s) = +520 kJ/mol
[tex]\mathtt{I_2_{(g)} \to 2I_{(g)} }[/tex]
The Bond Energy of I₂(g) = 151 kJ/mol
[tex]\mathtt{I_{(g)} + e^- \to I^-_{(g)}}[/tex]
The electron affinity of I(g) = -295 kJ/mol
Heat of sublimation: Sublimation is the process of changing of a solid matter into gas without passing through the liquid stage, Now, the molar heat of sublimation is the amount of energy that must be added to a mole of solid to turn it directly into a gas without any interference through the liquid phase provided the pressure is constant.
From the above reactions: The heat of sublimation of Li(s) can be calculated by the sum total of the following.
[tex]\mathtt{Li_{(s)} + \dfrac{1}{2} I_2_{(g)} \to LiI_{(s)} \ \ -292 kJ/mol} \\ \\\mathtt{I_{(g)} \to \dfrac{1}{2} I2(g) \ \ -75.5 kJ/mol} \\ \\ \mathtt{I^-(g) \to I(g) + e^- \ \ +295 kJ/mol} \\ \\ \mathtt{LiI(s) \to Li^+_{(g)} + I^-_{(g)} \ \ +753 kJ/mol} \\ \\ \mathtt{Li^+_{(g)} + e^- \to Li(s) \ \ -520 kJ/mol} \\ \\[/tex]
[tex]\mathtt{Li(s) \to Li(g)}[/tex] = (-292 +(-75.5)+295+753+(-520)) kJ/mol
[tex]\mathtt{Li(s) \to Li(g)}[/tex] = 160.5 kJ/mol
Heat of sublimation of Li(s) = 160.5 kJ/mol
what is cytoplasm ? what does it contain?
Answer:
Cytoplasm is a thick solution that fills each cell and is enclosed by the cell membrane. It is mainly composed of water, salts, and proteins. All of the organelles in eukaryotic cells, such as the nucleus, endoplasmic reticulum, and mitochondria, are located in the cytoplasm.
Answer:
Explanation:
Cytoplasm is a thick solution that fills each cell and is enclosed by the cell membrane. It is mainly composed of water, salts, and proteins. All of the organelles in eukaryotic cells, such as the nucleus, endoplasmic reticulum, and mitochondria, are located in the cytoplasm. ...
Suppose you see an advertisement for a video game that claims you can actually fly around inside your home while you play it. What do your scientific literacy and critical thinking skills lead you to think about that claim?
Answer:
Scientific literacy and critical thinking skills will nullify the claims made in the advertisement.
Explanation:
The claims made in the advertisement contradict the scientific laws and the person who understands the scientific theories can easily understand that. Critical thinkers may derive rational insights from a collection of facts, and distinguish between relevant and less important reasons for problem-solving or decision making. Therefore on objectively evaluating scientific theories, we conclude to a rational decision, that is the claims are false.
8.310x10^2 – 7.210x10^1
[?]x10^[?]
Answer:
[tex]7.589\times 10^{2}[/tex]
Explanation:
The expression can be solved mathematically as follows:
1) [tex]8.310\times 10^{2}-7.210\times 10^{1}[/tex] Given
2) [tex]8.310\times 10^{1+1} - 7.210\times 10^{1}[/tex] Definition of sum
3) [tex](8.310\times 10^{1})\times 10^{1}-7.210\times 10^{1}[/tex] [tex]a^{m+n} = a^{m}\cdot a^{n}[/tex]/Associative property
4) [tex](8.310\times 10^{1}-7.210)\times 10^{1}[/tex] Distributive property
5) [tex](83.100-7.210)\times 10^{1}[/tex] Multiplication
6) [tex]75.89\times 10^{1}[/tex] Subtraction.
7) [tex](7.589\times 10^{1})\times 10^{1}[/tex] Multiplication/Associative property
8) [tex]7.589\times (10^{1}\times 10^{1})[/tex] Associative property
9) [tex]7.589\times 10^{2}[/tex] [tex]a^{m+n} = a^{m}\cdot a^{n}[/tex]/Result
a. For a chemistry lab final exam, a high school chemistry student was given a 1-mole sample of CaCl2 and a 1-mole sample of MgCl2 but was not told which sample was which. He was to identify the powders.
He looked up the enthalpies of formation for both of the chemicals and calculated the ΔHreaction for dissolving each powder: CaCl2 (s) Ca 2+ (aq) + 2Cl – (aq), and MgCl2 (s) Mg 2 (aq) + 2Cl – (aq). He then put each powder in a coffee-cup calorimeter and added water.
When sample A dissolved, the temperature increased by 0.74°C. When sample B dissolved, the temperature increased by 0.39°C. Which chemical was A, and which was B? Use the table of enthalpies of formation to help you. Explain your reasoning.
Ca^2+ ion is smaller than Mg^2+ ion hence it has a greater heat of formation or lattice energy.
When a crystal lattice is formed, the energy that is released if the component ions of the compound are brought together from infinity is called the lattice energy. It is the energy released when a crystal lattice is formed from its component ions.
The question lets us know that the heat released by the compounds depends on the energy released upon formation of the compound. Hence, the higher the energy released upon formation, the higher the magnitude of heat released upon dissolution of the compound.
Recall that lattice energy depends on the size of the ions. Thus, the smaller the ions, the higher the lattice energy.
Ca^2+ is smaller than Mg^2+ hence more energy is given off when CaCl2 is formed than when MgCl2 is formed.
As stated above, the greater the lattice energy, the greater the heat released when the lattice dissolves and the higher the rise in temperature.
Putting all these together, Sample A must be CaCl2 while sample B must be MgCl2.
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A sealed gas syringe which can move freely contains 60 cm³ of air.Thd atmospheric pressure is 101 kPa.What is the pressure of the enclosed gas?
the volume of a gas is 568.4 ml at 23.2 if the temperature is increased to 93.4 without changing the pressure what is the new volume of the gas ?
Answer:
Do not incinerate "why the gas in the gas is initially at 23degree and 360kPa and the can has a volume of 350Ml
D
A two digit number is such that the sum of the ones and the tens digits is tens.If the digits are reversed,the new number formed exceeds the originals numbers by 54.Find the number.
Answer:
Explanation:
Let the no in the ones place be x
And the no in the tens place be 10 - x
Original no = 10 ( 10 - x ) + x
= 100 - 10x + x
= 100 - 9x
Reversed no = 10 - x + 10 ( x )
= 10 - x + 10 x
10 + 9x
According to the question,
the new number formed exceeds the originals numbers by 54.
10 + 9x = 100 - 9x + 54
10 + 9x = 154 - 9x
By transposing,
9x + 9x = 154 - 10
18 x = 144
x = 144 / 18
x = 8
∴ Digit in ones place = x = 8
Digit in tens place = 10 - x = 10 - 8 = 2
So the number = 28
( You can also recheck it by adding the ones and tens digit
8 + 2 = 10
In the question, the sum of ones and tens digit in ten )
Hope this helps
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fill in the blanks with the words given below-
[Atoms, homogeneous, metals, true, saturated, homogeneous, colloidal, compounds, lustrous]
1.An element which are sonorous are called................
2.An element is made up of only one kind of ....................
3.Alloys are ............................. mixtures.
4.Elements chemically combines in fixed proportion to form ........................
5. Metals are................................... and can be polished.
6. a solution in which no more solute can be dissolved is called a .................... solution.
7. Milk is a .............. solution but vinegar is a .................. solution.
8. A solution is a ................... mixture.
pls help, could not get these answers
Answer:
1. Metal.
2. Atom.
3. Homogeneous
4. Compounds.
5. Lustrous
6. Saturated.
7. Colloidal; true.
8. Homogeneous.
Explanation:
1. An element which are sonorous are called metal.
2. An element is made up of only one kind of atom.
3. Alloys are homogeneous mixtures.
4. Elements chemically combines in fixed proportion to form compounds.
5. Metals are lustrous and can be polished.
6. A solution in which no more solute can be dissolved is called a saturated solution.
7. Milk is a colloidal solution but vinegar is a true solution.
8. A solution is a homogeneous mixture.
what is meant by the term "boiling point of water"
Answer:
boiling point, temperature at which the pressure exerted by the surroundings upon a liquid is equaled by the pressure exerted by the vapour of the liquid; under this condition, addition of heat results in the transformation of the liquid into its vapour without raising the temperature
in case of water boiling point bring 0 degree
Answer:
it is the temperature at which water starts to boil. the temperate is 100°C or 212°F
what are the useful of carbon monoxide?
Answer:
carbon monoxide is strong reducing agent.carbon monoxide used in the extraction of pure metals of their ores.
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take an onion and one jam bottle insert the roots of onion in the jam bottle for five days . after five days observe the growth in the roots of onion which is submerged in jam bottle. write observation here
Answer:
It is noticed that after five days, there is elongation of the root cells in the roots of onion in the jam bottle
Explanation:
It is noticed that after five days, there is elongation of the root cells in the roots of onion in the jam bottle. The growth of a plant is due to the availability of the growing and dividing cells in the meristematic regions of the apical meristems. (stem cells). This site are active site for elongation and differentiation of the stem tissues. In the apical meristem of the root cells, the cells have the potential to carry out mitosis and cell division repeatedly in order to generate newer cells for extension and development of stems and leaves. With each cell division, one cell remains in the meristem which the other increases in size and differentiate due to different genomic expression to form the meristem regions which eventually becomes the stem structure.
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Which of the following is the best definition of a chemical property?
A. The solubility of salt.
B. The ability of gunpowder to explode.
C. The ability of something to undergo a change or reaction.
D. Something that can be observed or measured without changing the identity of the substance.
Answer:
The B. Is perfect match of a definition of chemical property.
Explanation:
The ability of gunpowder to explode.
The ability of gunpowder to explode is the best definition of a chemical property.
What is chemical property?The change of one type of matter into another type of matter and inability to change into the previous forms is called a chemical property. Examples of chemical properties include reactivity and heat of combustion.
So we can conclude that the ability of gunpowder to explode is the best definition of a chemical property.
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Write down the dissolution equation for nickel(II) perchlorate dissolving in water. (Perchlorate is a polyatomic ion with the formula ClO41-.) If four moles of the ionic compound are dissolved, then how many moles of the ANION are present in the solution?
Answer:
Ni(ClO₄)₂(aq) ⇒ Ni²⁺(aq) + 2 ClO₄⁻(aq)
8 mol ClO₄⁻
Explanation:
Let's consider the dissolution equation for nickel(II) perchlorate dissolving in water.
Ni(ClO₄)₂(aq) ⇒ Ni²⁺(aq) + 2 ClO₄⁻(aq)
The molar ratio of Ni(ClO₄)₂ to ClO₄⁻ is 1:2. If 4 moles of Ni(ClO₄)₂ are dissolved, the moles of ClO₄⁻ formed are:
4 mol Ni(ClO₄)₂ × (2 mol ClO₄⁻/ 1 mol Ni(ClO₄)₂) = 8 mol ClO₄⁻
If alkali A has a pH value of 13 and alkali B has a pH value of 9, explain which is most likely to be used in indigestion tablets as a remedy for excess stomach acid. *
Answer:
Alkalai B
Explanation:
B because its a weak alkali ie baking soda ph 8.3(sodium bicarbonate)which is used as a remeady of heartburns and stomach acids.
-K-12 Scientific Method
3/10
A(n)
simply states what will be observed and always
true, but does not explain why.
Answer:
The correct answer is - scientific law.
Explanation:
A scientific law is an explanation to a well observed phenomenon of the world which is found true every time tested and universal proven fact, but the reason behind the phenomenon and its existence.
To explain the scientific law there will be various explanation that are called scientific theory, however these theories can not be proved.
Thus, the correct answer is - scientific law.
CO2(g) + H2(g)
cog) + H2O(1)
What is being oxidized?
carbon
O carbon dioxide
oxygen
hydrogen
Answer:
Hydrogen
Explanation:
This may be wrong but I can't really tell because of how you have written the question
Answer: The answer is D. Hydrogen
Explanation:
I took the test
Does the following word describe a theory, law, or both
“Simple”
A) LAW
B) THEORY
C) BOTH THEORY AND LAW
Answer:
B
Explanation:
I would say theory since a law is already set and proven by evidence. Theories arent necessarily proven.
balance this equation
Al2 O3 + HCL → Al Cl3 + H2O
Answer:
[tex]{ \sf{Al _{2} O _{3(s)} + 6HCl _{(aq)} → 2Al Cl _{3(aq)} + 3H _{2} O _{(l)} }}[/tex]
Answer:
I think you have to put a coefficient of 6 in front Hcl,and a 2 infront of AlCl3 then a 3 in front of H2O,so that you can have 2 Al on both sides,6 Hcl,6 Cl and 3 o.
Al2O3+6HCl--->2AlCl3+3H2O.
I hope this helps
Explain Froath Flotation Method!
Explanation:
a process for separating minerals from gangue by taking advantage of the differences in their hydrophobicity.
I believe that is accurate
hope this helped have a nice day
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Using complete sentences, explain how to predict the products and balance the reaction between sulfuric acid and potassium hydroxide. H2SO4 + KOH ⟶
Answer:
The answer to your question is given below.
Explanation:
The reaction of sulfuric acid and potassium hydroxide is called neutralisation.
Neutralisation is a reaction involving an acid and a base which produces salt and water only.
For the react between sulfuric acid, H2SO4 and potassium hydroxide, KOH, we can predict the products obtained as follow:
H2SO4 + KOH —>
In solution, H2SO4 and KOH will dissociate as follow:
H2SO4(aq) —> 2H^+(aq) + SO4^2-(aq)
KOH(aq) —> K^+(aq) + OH^-(aq)
H2SO4 + KOH —>
2H^+(aq) + SO4^2-(aq) + K^+(aq) + OH^-(aq) —> K^+(aq) + SO4^2-(aq) + 2H^+(aq) + OH^-
H2SO4 + KOH —> K2SO4 + H2O
Now, we can balance the above equation as follow:
H2SO4 + KOH —> K2SO4 + H2O
There are 2 atoms K on right side and 1 atom on the left side. It can be balance by writing 2 in front of ko as shown below:
H2SO4 + 2KOH —> K2SO4 + H2O
There are 2 atoms of H on the right side and a total of 4 atoms on the left side. It can be balance by writing 2 in front of H2O as shown below:
H2SO4 + 2KOH —> K2SO4 + 2H2O
Now,the equation is balanced.
Answer:
Given the reactants, H2SO4 and KOH, we are asked to determine the product(s) of the reaction. Since H2SO4 is an acid and KOH is a base. This is a neutralization reaction, thus, the products are salt and water.
So, H+ from H2SO4 will react with OH- from KOH forming H2O. K+ will also react with SO4 2- forming K2SO4. Therefore, the balanced reaction will be:
H2SO4 + 2KOH ---> K2SO4 + 2H2O
Explanation:
A machine uses filtration to separate a component from orange juice. Which component does the machine most likely separate from the mixture?(1 point)
water
water
pulp
pulp
sugar
sugar
pigment
Which method of separation would be most appropriate for separating a mixture of water and alcohol?(1 point)
chromatography
chromatography
distillation
distillation
filtration
filtration
evaporation
Which method separates components of a mixture according to how quickly the particles travel through a medium?(1 point)
chromatography
chromatography
filtration
filtration
evaporation
evaporation
distillation
The boiling point of water is 100ºC. The boiling point of acetone is 56ºC. Which statement about distilling a mixture of acetone and water is correct?(1 point)
Acetone remains in the original container.
Acetone remains in the original container.
Acetone is captured and cooled.
Acetone is captured and cooled.
Water is collected as it leaves the mixture.
Water is collected as it leaves the mixture.
Water will vaporize from the mixture before acetone.
Substance A and substance B are mixed together. To separate the mixture, water is added, and substance A is filtered out. Then, the remaining liquid is heated to remove the water, leaving a residue of substance B. Which statement about substance A and substance B could be correct?(1 point)
Substance A is rice, and substance B is sugar.
Substance A is rice, and substance B is sugar.
Substance A is sand, and substance B is alcohol.
Substance A is sand, and substance B is alcohol.
Substance A is alcohol, and substance B is salt.
Substance A is alcohol, and substance B is salt.
Substance A is sugar, and substance B is instant coffee.
Pulp
distillation
chromatography
Acetone is captured and cooled.
Substance A is rice, and substance B is sugar.
To separate the components of a mixture the substances to be separated must differ in a given physical property.
In chemistry, there are diverse separation techniques used to separate the components of a mixture. Separation depends on differences in a given physical property such as boiling point, solubility in a solvent, difference in particle size etc.
Filtration can be used to separate a solid from a liquid hence it can be used to separate pulp from orange juice.
To separate water and alcohol, distillation is used because such a separation depends on the difference in the boiling points of water and alcohol. Water boils at a higher temperature than alcohol hence the mixture can be separated by distillation.
Chromatography is a method of separation that is dependent on how quickly a the components of a mixture move through a stationary phase.
Acetone has a lower boiling point than water hence it collected first and cooled before water.
Clearly, substance A must be a solid since it is filtered out after adding water. Substance B must be a water soluble substance which can be recovered from water by evaporation to dryness. Hence substance A is rice, and substance B is sugar.
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what do you mean by Arsenic Pollution?
Arsenic contamination of groundwater is a form of groundwater pollution which is often due to naturally occurring high concentrations of arsenic in deeper levels of groundwater.Arsenic contamination of ground water is found in many countries throughout the world, including the US.
A mineral sample has a mass of 35 g. When it is dropped into a graduated cylinder with 25mL of water, the volume of the water rises to 35 mL. Using this data, determine the density of the sample.
Answer:
3.5g/ml
Explanation:
density=mass/volume
the mass of the mineral we have been given to be 35g
and it's volume is found by subtracting the initial volume from the final volume which is 35ml-25ml=10ml
Answer:
[tex]\boxed {\boxed {\sf 3.5 \ g/mL}}[/tex]
Explanation:
The density of an object is the mass per unit volume, so the formula is:
[tex]\rho= \frac {m}{v}[/tex]
We know the mass of the mineral sample is 35 grams.
We have to calculate the volume. The volume was found using water displacement. An amount of water was put in a graduated cylinder, then the object was dropped in. The volume is the difference between the final water level and the initial water level.
v= final water - initial water v= 35 mL - 25 mL v= 10 mLNow we know the mass and volume of the mineral sample.
m= 35 g v= 10 mLSubstitute the values into the formula.
[tex]\rho= \frac{35 \ g}{10 \ mL}[/tex]
Divide.
[tex]\rho = 3.5 \ g/mL[/tex]
The density of the mineral sample is 3.5 grams per milliliter.
please help :) How can scientists ensure that their data are reliable? A) by making a single observation B) by recording values without units C) by keeping the results private D) by repeating trials during an experiment
Answer:
D. by repeating trials during an experiment
Explanation:
chile its actually d
Explanation:
Which of the following is an acid-base neutralization reaction? (1 point) Sn + 2HBr yields SnBr2 + H2 HCl + KOH yields KCl + H2O 2AlCl3 + 3Ca(OH)2 yields 2Al(OH)3 + 3CaCl2 2C2H6 +7O2 yields 4CO2 + 6H2O
Answer:
HCl + KOH ⇒ KCl + H₂O
Explanation:
Which of the following is an acid-base neutralization reaction?
Sn + 2HBr ⇒ SnBr₂ + H₂. NO. This is a single displacement reaction.
HCl + KOH ⇒ KCl + H₂O. YES. An acid reacts with a base to form salt and water.
2AlCl₃ + 3Ca(OH)₂ ⇒ 2Al(OH)₃ + 3CaCl₂. NO. This is a double dispacement reaction.
2C₂H₆ +7O₂ ⇒ 4CO₂ + 6H₂O. NO. This is a combustion reaction.
A spontaneous reaction occurs when the sign of free energy is
A: Neutral
B: Zero
C: Positive
D: Negative
why do scientist need govermental funding
It id desired to increase thr volume of gas by 20% without changing the pressure .To what temperature the gas must be heated if the initial temperature of the gas is 27degree celcius?
Answer:
32.4°C
Explanation:
Consider the following expression:
P•V/T =P'•V'/T'
Where P and P' are respectively the initial and the final pressure, V and V's are respectively initial and final volume, and T and T' are respectively initial and final temperature.
We know that the pressure cannot change, so it means that P = P'
We also know that the volume must be increased in 20%, and if we multiply the volume by 1.2 is like increase it in 20%, so we can write that V' = 1.2•V, and changing a little more we can write that V'/V = 1.2
So let's do some maths:
P•V/T = P'•V'/T'
T'•P•V/T = P'•V'
T'•P•V = P'•V'•T
T'=P'•V'•T/P•V
We know that P'=P so the division is equal to 1:
T'= 1•V'•T/V
We also know that V'/V = 1.2, so:
T' = 1.2•T
And we know the value of T, it's 27, so now we just have to solve it:
T' = 1.2•27
T' = 32.4°C