Answer:
Empirical evidence - B - helps scientists understand the natural world.
Explanation:
Definition from the web," Empirical evidence is information acquired by observation or experimentation. Scientists record and analyze this data. The process is a central part of the scientific method. "
The scientific method-The scientific method begins with scientists forming questions, or hypotheses, and then acquiring the knowledge through observations and experiments to either support or disprove a specific theory. "Empirical" means "based on observation or experience," according to the Merriam-Webster Dictionary. Empirical research is the process of finding empirical evidence. Empirical data is the information that comes from the research.
Before any pieces of empirical data are collected, scientists carefully design their research methods to ensure the accuracy, quality and integrity of the data. If there are flaws in the way that empirical data is collected, the research will not be considered valid.
The scientific method often involves lab experiments that are repeated over and over, and these experiments result in quantitative data in the form of numbers and statistics. However, that is not the only process used for gathering information to support or refute a theory.
This helps scientists by -Identifying empirical evidence in another researcher's experiments can sometimes be difficult. According to the Pennsylvania State University Libraries, there are some things one can look for when determining if evidence is empirical:
Can the experiment be recreated and tested?Does the experiment have a statement about the methodology, tools and controls used?Is there a definition of the group or phenomena being studied?I have no clue how to even start this, any help is appreciated!
A sample of 2.54 moles of iron (III) oxide is reacted with 4.56 moles of carbon monoxide to produce iron metal and carbon dioxide. Using the balanced equation below, predict which is the limiting reactant and the maximum amount in moles of carbon dioxide that can be produced.
Fe2O3 + 3CO → 2Fe + 3Co2
A. Iron (III) Oxide, 7.62 moles
B. Carbon monoxide, 5.34 moles
C. Iron (III) oxide, 2.63 moles
D. Carbon monoxide, 4.56 Moles
Answer:
Option D. Carbon monoxide, 4.56 Moles
Explanation:
The balanced equation for the reaction is given below:
Fe₂O₃ + 3CO —> 2Fe + 3CO₂
From the balanced equation above,
1 mole of Fe₂O₃ reacted with 3 moles of CO to produce 3 moles of CO₂.
1. Determination of the limiting reactant.
From the balanced equation above,
1 mole of Fe₂O₃ reacted with 3 moles of CO.
Therefore, 2.54 moles of Fe₂O₃ will react with = 2.54 × 3 = 7.62 moles of CO.
From the calculation made above, we can see that it will take higher amount of CO (i.e 7.62 moles) than what was given (i.e 4.56 moles) to react completely with 2.54 moles of Fe₂O₃. Therefore, CO is the limiting reactant and Fe₂O₃ is the excess reactant.
2. Determination of the maximum amount of carbon dioxide CO₂ produced.
In this case, the limiting reactant will be used since all of it is consumed by reaction.
The limiting reactant is CO and the maximum amount of CO₂ produced can be obtained as follow:
From the balanced equation above,
3 moles of CO reacted to produce 3 moles of CO₂.
Therefore, 4.56 moles of CO will also react to produce 4.56 moles of CO₂.
Thus, the maximum amount of CO₂ produced is 4.56 moles
Summary:
Limiting reactant => carbon monoxide, CO
Maximum amount of carbon dioxide, CO₂ produced = 4.56 moles
Thus, option D gives the correct answer to the question.
Why do buffer systems use either a weak acid or a weak base?
Weak acids and weak bases do not react easily.
Weak acids and weak bases are partially dissociated.
Weak acids and weak bases are unaffected by temperature.
Weak acids and weak bases are found in abundance on the earth.
Answer:
Weak acids and weak bases are only partially dissociated.
Explanation:
When a small amount of an acid or a base is added to water (or a solution of some strong acid or base of some certain [tex]pH \![/tex],) the [tex]pH[/tex] of that solution tends to change significantly.
In contrast, when the same amount of acid or base is added to a buffer system of some certain [tex]pH\![/tex], the [tex]pH[/tex] of this system tends to change by a much smaller amount.
Weak acids and weak bases dissociate only partially. That allows the buffer solutions to contain a large reservoir of both the (undissociated) weak acid (or weak base) and the corresponding conjugate ion, while maintaining the required [tex]pH[/tex].
This reservoir of the partially-dissociated weak acid (or weak base) and its conjugate ion allows the buffer system to absorb [tex]\rm H^{+}[/tex] and [tex]\rm OH^{-}[/tex] that were added to the solution without much change to the [tex]pH[/tex].
For example, consider a [tex]1\; \rm L[/tex] buffer solution that initially included [tex]0.1\; \rm mol[/tex] of acetic acid [tex]\rm CH_3COOH[/tex] (a weak acid with [tex]pK_\text{a} = 4.765[/tex]) and [tex]0.1\; \rm mol\![/tex] of sodium acetate [tex]\rm CH_3COONa[/tex]. The [tex]pH[/tex] of this solution would be [tex]4.765[/tex].
In contrast, if a solution of [tex]\rm HCl[/tex] (a strong acid) and an equal amount of [tex]\rm NaCl[/tex] also needs to be [tex]4.765[/tex], only [tex]10^{-4.765}\; \rm mol \approx 0.0000172\; \rm mol[/tex] of each species could be included.
Assume that [tex]0.001\; \rm mol[/tex] of [tex]{\rm NaOH}\, (s)[/tex] is added to the buffer solution of [tex]\rm CH_3COOH[/tex] and [tex]\rm CH_3COONa[/tex]. The quantity of the partially-dissociated weak acid in this solution is much larger than that of the [tex]\rm OH^{-}[/tex] added to the solution.
Only a small portion of the weak base would be consumed.The [tex]pH[/tex] of the solution would likely change by less than [tex]0.001[/tex].
In contrast, assume that [tex]0.001\; \rm mol[/tex] of [tex]{\rm NaOH}\, (s)[/tex] is added to the [tex]1\; \rm L[/tex] solution with [tex]0.0000172\; \rm mol[/tex] of [tex]\rm HCl[/tex] (fully-dissociated) and [tex]\rm NaCl[/tex].
All the [tex]\rm HCl\![/tex] in this solution would be consumed. The [tex]pH[/tex] of this solution would go well above [tex]7[/tex].
Answer:
Weak acids and weak bases are partially dissociate
Explanation:
I took the test and got 100%
Pls help me out ASAP
A sample of nitrogen dioxide, NO, is held at a temperature of 1195 K in a container with a volume of 25 liters and a pressure of 560 atm. How many grams of NO, are present in the container? Round your answer to two significant figures.
A) 5300g
B) 3300g
C)6600g
D)4900g
There is no such thing as heat.
True
False
Answer:
false
Explanation:
Answer:
false
Explanation:
Which best explains how rotation affects the colors we see in the sky at dawn and dusk?
A.As dawn and dusk, the light from the Sun is fading and phases through all the colors of a prism in a cycle.
B.At dawn and dusk the rotation of Earth slows down so the light from the increased sunlight creates colors.
C.At dawn and dusk, sunlight is closer to Earth’s curved surface, refracting in the atmosphere, creating colors.
D.At dawn and dusk, Earth has rotated closer to the Sun, so the heat creates the colors in the sky.
10 point
10 point
I think that the answer is C.)
It makes the most sense because one or two of the other options talk about the sun getting closer to the earth which makes no sense. Also, the Earth's spinning speed does not slow down so that rules out option B. Lastly, the answer cannot be A whereas the sun's light does not fade, rather the Earth spins with a shadow casting over its back due to no sunlight on that facing side.
Hope this helps and have a nice day.
-R3TR0 Z3R0
Answer:
it's c
Explanation:
i took test
Calculate the number of moles of H2 in 63.0g
Answer:
6 moles
Explanation:
hope this helps:)
what do The representative elements include
Answer:
aajajjajajajajajajajajdsjsjjx jajajjajajajajaisjn
Explanation:
Which substance is not a fossil fuel?
What causes the sugar to dissolve in water?
Answer:
Sugar dissolves in water because energy is given off when the slighty polar sucrose molecules form intermoleeular bonds with the polar water molecules.
Explanation:
Answer:
PORS U N DISOLVENTE ELAGA YU E LAZUCR UAE SOLN TOU
Explanation:
PLEASE HELP ME ON QUESTION 6 ASAP!!!!!!!!!!!
Answer:
b tissues,cells,organs,organ system,organisms,populations
Tissues, Cells, Organs, Organ Systems, Organsims, Population. the correct answer is B
Approximately how far will a p-wave travel in 4 minutes?
Answer:
2000 (km)
Explanation:
:)
12. In rocket fuel (as in many of the balloons we blow up in class), hydrogen gas (H2) reacts with oxygen gas (O2) to form water vapor. a) Write a balanced reaction for the process. b) Suppose you have a mini rocket and access to 2.50 L of oxygen gas and 4.00 L of hydrogen gas. If you use up all of the gas possible blasting off your rocket, how many liters of water vapor did you produce (at the same temperature as the original mixture)
Answer: a) [tex]2H_2(g)+O_2(g)\rightarrow 2H_2O(g)[/tex]
b) 4.00 L of [tex]H_2O[/tex] will be produced
Explanation:
a) The balanced chemical reaction is:
[tex]2H_2(g)+O_2(g)\rightarrow 2H_2O(g)[/tex]
b) According to avogadros law, equal moles of gases occupy equal volumes at same temperature and presure conditions.
According to stoichiometry :
2 L of [tex]H_2[/tex] require = 1 L of [tex]O_2[/tex]
Thus 4.00 L of [tex]H_2[/tex] will require=[tex]\frac{1}{2}\times 4.00=2.00L[/tex] of [tex]O_2[/tex]
Thus [tex]H_2[/tex] is the limiting reagent as it limits the formation of product and [tex]O_2[/tex] is the excess reagent.
As 2 L of [tex]H_2[/tex] give = 2 L of [tex]H_2O[/tex]
Thus 4.00 L of [tex]H_2[/tex] give =[tex]\frac{2}{2}\times 4.00=4.00L[/tex] of [tex]H_2O[/tex]
Thus 4.00 L of [tex]H_2O[/tex] will be produced
a. The balanced reaction for the process should be 2h_2(g) + O_2(g) ⇒2H_2O(g)
b. The number of liters of water vapor should be 4.00 liters of H_2O.
Avogadro's law:a. The balanced reaction for the process should be 2h_2(g) + O_2(g) ⇒2H_2O(g)
b. As per the law, the equal moles of gases occupied equal volumes at the similar temperature
So, the number of liters should be
= 2/2*4.00
= 4.00 of H_2O
Learn more about the reaction here: https://brainly.com/question/4417455
A student burns 1.50 mol C3H8 according to the following reaction:
C3H8 + 5O2 3CO2 + 4H2O.
How many grams of carbon dioxide are produced?
a. 1.98 × 10² g
b. 1.32 × 10² g
c. 4.40 × 10¹ g
d. 6.61 × 10¹ g
Answer:
I think the answer is A. 1.98 x 10^2 g
How do sounds change?
click volume button Explanation:
please help due in 1 hour. This is 7th grade science. & in return I’ll help you on something! 15 points
Answer: MCCCMC
Please. Mark as brainliest
At which point does condensation occur in this water cycle diagram?
The Water Cycle
B
D
OA A
ОВ. В
О с. С
OD. D
Answer: B
Explanation:
A is evaporation. B is condensation. C is precipitation.
Answer:
it would be b
Explanation:
b would be condensation
It takes______ dekaliters to make 100 L.
A.1000
B.1
C.10
D.0.1
Answer:
c
Explanation:
The data table shows the rate of the decomposition reaction of hydrogen
peroxide, H202. Which statement explains how the rate of the reaction
changes over time?
Answer:
b. the reaction slows down over time as the reactants get used up
Explanation:
just took the test, i hope this helps!!
make sure to take care of yourself :]
The statement " the reaction shows down over time as the reactant get used up." explains how the rate of reaction changes over time.
What is rate of reaction?The rate of reaction is defined as the ratio of the increase in product concentration per unit time to the decrease in reactant concentration per unit time. The rate of reaction varies greatly.
What is rate?The rate of a particular chemical reaction is calculated by dividing the rate of change in a reactant's or product's concentration by the coefficient from the given balanced equation.
What is reaction?Reactions are defined as the change of a chemical substance into an innovative substance through the formation and breaking of bonds among distinct atoms.
It can be seen that with the concentration, the rate of decomposition is also decreased. Generally, it is found that as per hour concentration and rate of decomposition decreases as well.
To know more about rate of reaction and rate
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A molecule which contains two atoms of the same or different
elements can be referred to as a ---- molecule.
Answer:
my network was gone so I cant
Answer:
Diatomic. molecule
hope it helps
and yr day will be full of happiness
13. Describe the flow of thermal energy.
Plz help
Answer: Thermal energy refers to the energy contained within a system that is responsible for its temperature. Heat is the flow of thermal energy. ... This energy is usually in the form of low-level thermal energy. Here, low-level means that the temperature associated with the thermal energy is close to that of the environment. hope this helps. Can u pls give me brainliest
Explanation:
A geologist conducts an investigation to determine the absolute age of a fossil. She then
repeats the procedure three times. Which BEST explains why she repeated the procedure
several times? (SC.6.N.1.1)
It helps her develop better procedures
It improves the accuracy of the results.
She wants all the results to be different.
She has more than one hypothesis to prove.
Answer:
Explanation:
Hehs
Ancient Romans built often out of bricks and mortar. A key ingredient in their mortar was quicklime (calcium oxide), which they produced by roasting limestone (calcium carbonate). 1. Write a balanced chemical equation, including physical state symbols, for the decomposition of solid calcium carbonate (CaCO3) into solid calcium oxide and gaseous carbon dioxide. CaCO3s→CaOs+CO2g 2. Suppose 48.0L of carbon dioxide gas are produced by this reaction, at a temperature of 260.0°C and pressure of exactly 1atm. Calculate the mass of calcium carbonate that must have reacted. Round your answer to 3 significant digits.
Answer:
110 g
Explanation:
Step 1: Write the balanced equation for the decomposition of calcium carbonate
CaCO₃(s) ⇒ CaO(s) + CO₂(g)
Step 2: Convert 260.0 °C to Kelvin
We will use the following expression.
K = °C + 273.15 = 260.0 + 273.15 = 533.2 K
Step 3: Calculate the moles of CO₂ produced
We will use the ideal gas equation.
P × V = n × R × T
n = P × V/R × T = 1 atm × 48.0 L/0.0821 atm.L/mol.K × 533.2 K = 1.10 mol
Step 4: Calculate the moles of CaCO₃ that reacted to produce 1.10 moles of CO₂
The molar ratio of CaCO₃ to CO₂ is 1:1. The moles of CaCO₃ that reacted are 1/1 × 1.10 mol = 1.10 mol.
Step 5: Calculate the mass corresponding to 1.10 moles of CaCO₃
The molar mass of CaCO₃ is 100.09 g/mol.
1.10 mol × 100.09 g/mol = 110 g
PHMWMHW(14 points):))));)))))
Answer:
a silly
Explanation:
Choose the options below that are true of a solution of a solid in a liquid. (select all that apply) Select all that apply: Most solids in solution exhibit a general trend of increasing solubility with increasing temperature. A seed crystal may be added to a supersaturated solution to precipitate excess solute. Most solids in solution will dissolve less with increasing temperature. A solution can be saturated at an elevated temperature and subsequently cooled to a lower temperature without precipitating the solute.
Answer:
Most solids in solution exhibit a general trend of increasing solubility with increasing temperature.
A seed crystal may be added to a supersaturated solution to precipitate excess solute.
Explanation:
For many solids dissolved in liquid water, the solubility increases with temperature. The increase in kinetic energy that comes with higher temperatures allows the solvent molecules to more effectively break apart the solute molecules that are held together by intermolecular attractions(Lumen Learning).
When a seed crystal is added to a supersaturated solution, excess solute begin to precipitate because the seed crystal now furnishes the required nucleation site where the excess dissolved crystals now begin to grow.
4. Diffuse reflection occurs when parallel light waves strike which surface?
Answer:
rough surface
Explanation:
Diffuse reflection occurs when parallel light waves strike a rough surface
Answer:
Rippling fountain
Explanation:
6 H2(g) + P4(5) → 4 PH:(9)
17 Solid phosphorus reacts with hydrogen gas to form phosphine gas (PH) as shown above What is
the theoretical yield of PH2 that can be formed when 400 g Ha reacts with 6.20 g P.?
A. 89.8 g PHS
B. 44 9 g PH
C 27 2 g PHA
D. 681 g PHI
For the reaction
3KOH+H3PO4⟶K3PO4+3H2O
how many grams of phosphoric acid, H3PO4, are needed to react completely with 89.7 g of potassium hydroxide, KOH?
Answer:
52.2 g
Explanation:
Step 1: Write the balanced equation
3 KOH + H₃PO₄ ⟶ K₃PO₄ + 3 H₂O
Step 2: Calculate the moles corresponding to 89.7 g of KOH
The molar mass of KOH is 56.11 g/mol.
89.7 g × 1 mol/56.11 g = 1.60 mol
Step 3: Calculate the moles of H₃PO₄ needed to react with 1.60 moles of KOH
The molar ratio of KOH to H₃PO₄ is 3:1. The moles of H₃PO₄ needed are 1/3 × 1.60 mol = 0.533 mol.
Step 4: Calculate the mass corresponding to 0.533 moles of H₃PO₄
The molar mass of H₃PO₄ is 97.99 g/mol.
0.533 mol × 97.99 g/mol = 52.2 g
Which of the following describes an exothermic reaction?
O A. AHt, reactants > AHf, products
B. AHF, reactants = AHf, products
O C. AHf, reactants = 0
O D. AHF, reactants < AHt, products
The option A describes an exothermic reaction.
i.e, ΔHt,reactant > ΔHt, product
What is exothermic reaction?The reaction in which energy is release during the formation of reaction is called exothermic reaction.
Mathematically,
ΔHf = ΔH(product) - ΔH(reactant)
For exothermic reaction, ΔHt,reactant > ΔHt, product
So,for exothermic reaction, ΔHf is negative.
Where,
ΔHf = Enthalpy of formation of reaction
ΔH(product) = enthalpy of formation of product
ΔH(reactant) = enthalpy of formation of reactant
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Sevin, the commercial name for an insecticide used to protect crops such as cotton, vegetables, and fruit, is made from carbamic acid. A chemist analyzing a sample of carbamic acid finds 0.8007 g of carbon, 0.9333 g of nitrogen, 0.2016 g of hydrogen, and 2.133 g of oxygen. Determine the empirical formula for carbamic acid. 7. When 1.916 g of titanium is strongly heated in a stream of pure oxygen, a metal oxide sample weighing 3.196 g results. Calculate the empirical formula of the oxide.
Answer:
Explanation:
Ratio of mass of C , N , H and O
= .8007 :0.9333:0.2016:2.133
Ratio of moles of C , N , H and O
= .8007/12 : .9333 / 14 : 0.2016 / 1 : 2.133/16
= .0667 : .0667: .2016 : .1333
= .0667 / .0667 : .0667 / .0667 : .2016 /.0667 : .1333 / .0667
= 1 : 1 : 3: 2
Hence empirical formula = CNH₃O₂
7 .
Weight of titanium Ti = 1.916 g
Weight of oxygen = 3.196 - 1.916 = 1.28 g
Ratio of weight of Ti and O
= 1.916 : 1.28
Ratio of moles of Ti and O
1.916/48 : 1.28/16 [ Molecular weight of Titanium is 48 ]
= .04 : .08
= .04/.04 : .08/.04
= 1 :2 .
Empirical formula
TiO₂
Which statement is true about a polyatomic ion?
Answer:
The correct answer is that it is made of atoms that are covalently bonded together.
Explanation:
Hope this helped Mark BRAINLEST!!!