Answer:
-1071 Joules
Explanation:
The Joule was introduced as the SI unit for energy in 1925. One calorie is equal to approximately 4.184 joules(J). This is a conversion factor that we can write two ways:
(1cal/4.184J) or (4.184J/1cal)
(265 cal)*(4.184J/1cal) = 1071 J
Since the energy is leaving the system, it should be written with a minus sign: -1071J
Answer:
1,108.76 joules
Explanation:
There are 4.184 joules per calorie
4.184 x 265 = 1,108.76
On a heating curve, in which section(s) would you use the equation, Q=mCΔT, to calculate the total heat required?
only on plateaus or flat parts of the curve
on a sloped part only if under 0oC
on a sloped part only if over 100oC
on all sloped parts of the curve
Answer:
all sloped parts
Explanation:
Sloped part of the curve - all as this would show a change in T ( or delta T)
the flat parts would involve no change in Temp
How many moles of NO2 form when
63.25 g N2O5 decompose?
2N₂O54NO₂ + O₂
Answer:
1.1713 moles
Explanation:
RFM of N2O5=108
Moles of N2O5= mass/RFM= 63.25/108=0.5856 moles
Mole ratio of N2O5:NO2= 2:4
Therefore moles of NO2= 4/2*0.5856= 1.1713 moles
what is the empirical formula for a compound if a sample contains 1.0 g of S and 1.5 g of O?
1.SO
2.SO3
3.S202
4. S203
Is the relationship between temperature and water density an inverse or direct relationship?
The relationship between temperature and water density is an inverse relationship.
Temperature:-A measure of the typical kinetic energy of the atoms or molecules in a system, the temperature is a physical variable that expresses hot and cold.
Density:-The definition of density is the mass of a substance per unit volume. Density is defined as the ratio of mass to volume, or mass per unit volume.
Relation between temperature and density:-An inverse relationship exists between temperature and density. The density of water drops because of the increased distance between water molecules as temperature rises. Water's density rises when its temperature drops, but only to a certain extent.
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PLS HELP
4. T or F X-rays, ultraviolet light, and gamma rays all can travel through interplanetary space, so they are examples of waves.
5. What happens to the amplitude of water waves as you get farther from the disturbance that caused them? Why?
4. True
5. The amplitude of the ripples decreases as the circumference of the circle increases.
What is a wave?A wave is a disturbance that moves energy from one place to another.
Radio waves, gamma-rays, visible light, and all the other parts of the electromagnetic spectrum are electromagnetic radiation. Electromagnetic radiation can be described in terms of a stream of mass-less particles, called photons, each travelling in a wave-like pattern at the speed of light. Hence, the statement is true.
As the disturbance moves outwards the energy it carries is spread over a larger and larger region called the wavefront. For example, the ripples in the water lie in a circle with an ever-increasing circumference. The amplitude of the ripples decreases as the circumference of the circle increases.
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The absorption spectrum of sodium is shown below. What do the two dark
vertical lines in the spectrum show about sodium atoms?
Absorption spectrum
700
600
500
400 nm
OA. A sodium atom gives off all wavelengths except those two when
an electron moves to lower energy levels.
OB. A sodium atom gives off those two wavelengths when an electron
moves to a higher energy level.
OC. Only those two wavelengths can cause an electron to move to a
higher energy level.
OD. All wavelengths except those two cause an electron to move to a
lower energy level.
SUBMIT
The two dark vertical lines in the spectrum shows that all wavelengths except those two cause an electron to move to a lower energy level. Hence, Option (D) is correct
What is Absorption Spectrum ?
A spectrum of electromagnetic radiation transmitted through a substance, showing dark lines or bands due to absorption at specific wavelengths.
The given fact is explained by the energy levels that electrons may be in are quantized, or vary by a specific amount.
When electrons go from one energy level to another, the difference in those energy level is a specific value, and not a range of values.
If they are transitioning upwards towards a higher energy, they will absorb the photons corresponding to the wavelength of light which has the specific amount of energy they need to ascend, resulting in dark lines.
Similarly, when the electrons transition from higher to lower energy, the same specific amount of energy is released and the emission spectrum shows lines in the places where the absorption spectrum was dark.
Hence, The two dark vertical lines in the spectrum shows that all wavelengths except those two cause an electron to move to a lower energy level. Therefore, Option (D) is correct
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a burning candle wax reacts with oxygen. after a glass jar is placed over it, the candle goes out. what is the limiting reactant?
Answer:
The Oxygen
Explanation:
When fire is covered, it goes out due to the lack of oxygen to maintain itself.
The limiting reactant in the experiment of the burning candle is oxygen.
What is a limiting reactant?A limiting reactant is a reactant which determines the amount of product that ca be formed in a given reaction.
The limiting reactant is always used up in a reaction, after which the reaction stops.
In the experiment of the burning candle, covering the candle with the glass prevents more oxygen from taking part in the reaction.
Therefore, the limiting reactant is oxygen.
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the hemiacetal below is treated with 18o-labeled methanol (ch3o*h) and acid. where will the label appear in the products?
The 18o-labeled methanol (CH3O*H) will appear in the products side at position b.
Position of 18o-labeled methanol in the products
The 18O label will appear at position b in the product as indicated in the image.
This methoxy group in the product formed in position b comes from the 18O-labeled methanol (CH3OH).
While the oxygens at positions a and c in the product come from the unlabeled hemiacetal.
Thus, the 18o-labeled methanol (CH3O*H) will appear in the products side at position b.
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PLEASE HELPNIM STUCK
Answer:
I think its C
Explanation: cuz the pictures indicate that is returns to "normal" last.
What is the simplest method of determining the composition of a compound?
Answer:
Chemical formulas tell you how many atoms of each element are in a compound, and empirical formulas tell you the simplest or most reduced ratio of elements in a compound. If a compound's chemical formula cannot be reduced anymore, then the empirical formula is the same as the chemical formula.
please give me brainliest
Which of the following is the correct balanced equation for the reaction in which methane (CH4) burns in atmospheric oxygen (0₂) to make carbon dioxide and water vapor?
Answer: [tex]\text{CH}_{4}+2\text{O}_{2} \longrightarrow \text{CO}_{2}+2\text{H}_{2}\text{O}[/tex]
Explanation:
The unbalanced equation is
[tex]\text{CH}_{4}+\text{O}_{2} \longrightarrow \text{CO}_{2}+\text{H}_{2}\text{O}[/tex]
Balancing this equation, we get:
[tex]\boxed{\text{CH}_{4}+2\text{O}_{2} \longrightarrow \text{CO}_{2}+2\text{H}_{2}\text{O}}[/tex]
How many moles of hydrogen
gas will be produced at the same
time as 138 g NaOH?
2Na+ 2H₂O → 2NaOH + H₂
Answer:
1.72 moles of H₂
Explanation:
The balanced equation
2Na+ 2H₂O → 2NaOH + 1C
tells us we'll get 1 mole of H₂ for every 2 moles of NaOH. We can express this as a molar ratio: (1 mole H₂)/(2 moles NaOH).
The reaction produces 138 g of NaOH. Divide this mass by the molar mass of NaOH (39.99 g/mole)to obtain moles NaOH:
138g NaOH/(40 g/mole) = 3.45 moles of NaOH.
To find the moles H₂ produced, we can multiply the moles NaOH by the molar ratio from above:
(3.45 moles NaOH)*((1 mole H₂)/(2 moles NaOH) = (3.45/2) moles H₂. [Note how the "moles NaOH" unit cancels, leaving just "moles H₂"]
We should produce 1.72 moles of H₂.
In a titration, 25.0 mL of a 0.40 M NaOH solution is used to neutralize 10.0 mL of HCl. Calculate the molarity of the acid.
The molarity of the HCl acid will be 0.001 M.
What is Neutralization ?A neutralization reaction is when an acid and a base react to form water and a salt and involves the combination of H⁺ ions and OH⁻ ions to generate water.
This is the neutralization of a strong acid (HCl) and a strong base (NaOH), which is ruled by this equation :
HCl (aq) + NaOH (aq) → NaCl (aq) + H₂O (l)
Mole Ratio : 1 mol HCl : 1 mol NaOH
Formula used ;
Molarity = number of moles / Volume (in liters)
Solve for n ;
n = M × V
Substitute values and compute ;
n = 0.40 M × 0.025 liter = 0.01 moles NaOH.
As the molar ratio is NaOH : HCl
Therefore, there will be same number mole for the HCl
Now, Molarity of HCl Solution ;
Molarity = n / volume
Molarity = 0.01 / 10
= 0.001 M HCl
Hence, The molarity of the HCl acid will be 0.001 M.
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The valence electrons found in metallic bonds are different from other bonds
because
A. their valance electrons are free-roaming
B.they allow conductivity of electricity
C.their valence electrons are immobile
D. They’re able to share electrons with other atoms
Answer:
their valence electrons are free roaming
A sample of gas collected at 685 mm Hg occupies 131 mL. At constant temperature, what pressure does the gas exert if the volume increases to 478 mL? a. 188 b. 1320 c. 128 d. -88.8
Answer:
a. P=188mmHg
Explanation:
A gas undergoing a change of volume and pressure at constant temperature (and not changing the number of molecules), follows Boyle's Law: [tex]P_1V_1=P_2V_2[/tex]
The units of these quantities can be any measure of pressure and volume, so long as long as the units are the same between beginning and ending conditions.
Substitute and solve:
[tex]P_1V_1=P_2V_2[/tex]
[tex](685[mmHg])(131[mL])=P_2(478[mL])[/tex]
[tex]\dfrac{(685[mmHg])(131[mL\!\!\!\!\!\!\!\!\!{--}])}{478[mL\!\!\!\!\!\!\!\!\!{--}]}=\dfrac{P_2(478[mL]\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{----})}{478[mL] \!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{----}}[/tex]
[tex]187.730125523[mmHg]=P_2[/tex]
Accounting for significant figures, [tex]P_2=188[mmHg][/tex]
For the reaction C+ 2H2 → CH4, how many grams of hydrogen are required to produce 5 moles of
methane, CH4 ?
Round your answer to the nearest tenth. If you answer is a whole number like 4, report the answer
as 4.0
Use the following molar masses. If you do not use these masses, the computer will mark your
answer incorrect.:
Element
Hydrogen
Carbon
Molar Mass
1
12
10 mol of H₂ required to produce 5 moles of methane (CH₄)
What is Mole ratio ?Mole Ratio is a conversion factor between compounds in a chemical reaction, that is derived from the coefficients of the compounds in a balanced equation.
The mole ratio is therefore used to convert between quantities of compounds in a chemical reaction.
Given reaction ;
C + 2H₂ -------> CH₄
from reaction 2 mol 1 mol
from the question x mol 5 mol (given)
Now,
x = 2 x 15 / 1 = 10 mol
= 10 mol of H₂.
Hence, 10 mol of H₂ required to produce 5 moles of methane (CH₄)
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Question 3 of 25
Which statement describes a question that can guide the design of a
scientific investigation?
OA. It asks about whether a controlled variable is necessary.
B. It asks about the preferred outcome of the investigation.
C. It asks about how the observations will be organized.
D. It asks about a cause-and-effect relationship between two
variables.
The statement that describes a question that can guide the design of a scientific investigation could be about the necessity of a controlled variable. The correct answer is A.
What is a controlled variable?It is a variable whose values are controlled by the researcher during the course of experimental investigations.
When designing an experiment, it is necessary to identify the different variables that would be involved for a successful investigation.
Variables can be independent, dependent, controlled, or constant. Identifying the necessary variables will help in designing the experiment.
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Ca is an atom. Why?
Help me asap pleased
Answer:
It has protons, neutrons and electrons
The difference in an area with high concentration and an area with low concentration is called.
The difference in an area with high concentration and an area with low concentration is called the concentration gradient.
What is Concentration Gradient ?
A concentration gradient occurs when the concentration of particles is higher in one area than another.
In passive transport, particles will diffuse down a concentration gradient, from areas of higher concentration to areas of lower concentration, until they are evenly spaced.
This difference in an area with high concentration and an area with low concentration is called the concentration gradient.
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the electron configuration for sodium is 1s22s22p63s1. which subshell is said to contain the valence electron(s) for sodium?
The subshell that contains the valence electron for sodium is the s subshell
Valence electronsValence electrons are the electrons located at the outermost shell of an atom
From the question, we are to determine the subshell that contains the valence electron(s) for sodium
The given electronic configuration for sodium is
1s²2s²2p⁶3s¹
The valence electron is the electron in the 3s orbital.
Hence, the subshell that contains the valence electron for sodium is s subshell
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PLEASE HURRY!! WORTH 50 POINTS!
A mixture of three noble gases has a total pressure of 1.25 atm. The individual pressures exerted by neon and argon are 0.68 atm and 0.35 atm, respectively. What is the partial pressure of the third gas, helium?
0.22 atm
0.33 atm
1.03 atm
2.28 atm
Answer:
P total = 1.25 atm
neon = 0.68 atm
argon= 0.35 atm
helium= x
1.25=0.68+0.35+x
1.25-0.68-0.35=x
x=0.22 atm
What’s the name of this compound?
Answer:
decane
Explanation:
decane has 10 carbon and 22hydrogen
Help!!! Will give brainliest to those who have the most accurate answer W/explanation!
Answer:
See below
Explanation:
Tap water, bottled water and lake water are all examples of FRESH WATER and likely have the same specific gravity ( or density) .
Ocean water is SALT WATER ....and depending on HOW MUCH salt is in the water, it can be quite a bit denser than fresh water ...which will allow the golf ball ( which is less dense) to float .
Select the correct answer from each drop-down menu.
Scientific theories are always
testable
. A theory may be changed as a result of
.
Scientific theories are always testable. A theory may be changed as a result of new observations.
What are Scientific theories ?A scientific theory is a set of laws, facts and hypotheses that have a complete vision of an aspect of reality.
It is a proposed explanation for a set of observable phenomena.
It allows in this way to organize and understand the observations and to be able to predict or provoke other future observations.
Theories can be modified or improved as more information is collected.
That is, theories can continue to be tested indefinitely, and eventually rejected, if the tests lead to it.
Therefore, a scientific theory is testable by using a research method.
As mentioned, any theory can be tested or rejected as more information is collected.
This information to prove or reject theories are interpretations of observable facts, which generates new statements or allows to accept those already included in the theory.
Then, a theory may be changed as a result of new observations.
Finally, scientific theories are always testable. A theory may be changed as a result of new observations.
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Answer:
testable & new observations
Explanation:
1. What were the concentrations of samples A and B?
2. What are some possible sources of error in a titration experiment? Share some tips to minimize errors with your classmates.
3. What is an example of a problem that can be solved using titration in the real world?
4. Phenolphthalein was used as the indicator in the experiment. The universal indicator exhibits the rainbow of colors for the entire pH range. Do you think using the universal indicateor would also work for this lab? Justify your answer, and explain why you agree or disagree.
A food processing company might use titration to calculate the precise amount of salt in a particular food stuff.
What is Titration ?A process of determining the concentration of a dissolved substance in terms of the smallest amount of reagent of known concentration required to bring about a given effect in reaction with a known volume of the test solution
The general source of error in titration has been;
The measurement of volume in burette by at the lower meniscus. It has been corrected with the application of measurement at eye level.The air bubble in the burette results in the incorrect measurement of the volume of burette. It can be corrected by tapping the burette or by slowing adding the solution to remove the bubble.The absence of rinsing the burette before use has been resulted in the water droplets that has been results in the incorrect measurement and dilution of the solution. The correction has been made by the use of dried burette.A food processing company might use titration to calculate the precise amount of salt in a particular food stuff.
It can also be used to determine the concentration of vitamin C or vitamin E additives in foods.
Universal indicator can also work as the indicator in the lab.
When universal indicator is added to a solution, the color change can indicate the approximate pH of the solution.
Acids cause universal indicator solution to change from green toward red whereas, bases cause universal indicator to change from green toward purple.
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If u can write like a sentence or two would be amazing:
Outline the differences between respiration and combustion.
Respiration is the process of oxidation of food materials like glucose, Amino acids, fatty acids to water and carbon dioxide. Respiration does not require any external heat to carry on the process. Combustion is only done by applying external heat to the sugar molecule to burn.
Calculate the mass of slver n grams depostedwhen 10.920 coulombs of electrcty s passed through a soluton of slver salt. (Ag= 180, 1 faraday-96500C)
N₂(g) + 3H₂(g) → 2NH3(g)
224 L of nitrogen reacts with
excess hydrogen at 2773 K and
95.0 atm. How many moles of
nitrogen react?
Answer:
93.5 moles N₂
Explanation:
To find the moles, you need to use the Ideal Gas Law. The equation looks like this:
PV = nRT
In this equation,
-----> P = pressure (atm)
-----> V = volume (L)
-----> n = number of moles
-----> R = constant (0.0821 atm*L/mol*K)
-----> T = temperature (K)
You can plug the given values into the equation and simplify to find moles. The final answer should have 3 sig figs to match the lowest number of sig figs among the given values.
P = 95.0 atm R = 0.0821 atm*L/mol*K
V = 224 L T = 2773 K
n = ?
PV = nRT
(95.0 atm)(224 L) = n(0.0821 atm*L/mol*K)(2773 K)
21280 = n(227.6633)
93.5 = n
Answer:
93.5 moles N₂
Explanation:
You can plug the given values into the equation and simplify to find moles. The final answer should have 3 sig figs to match the lowest number of sig figs among the given values.
P = 95.0 atm R = 0.0821 atm*L/mol*K
V = 224 L T = 2773 K
n = ?
PV = nRT
(95.0 atm)(224 L) = n(0.0821 atm*L/mol*K)(2773 K)
21280 = n(227.6633)
93.5 = n
Explanation:
Hello can someone help me please and thanksss
the equation of the parabola is given as [tex]y = 1/4 (x-6)^2 +1[/tex]. D
How to find the parabolaGiven the focus(6,2) and the directrix, y = 0
Use the formula
[tex]\sqrt{(x-6)^{2} + (y-2)^{2} } }[/tex] = (y - 0)
Find the square of both sides, square root is removed from the side with it and square added on the other side
[tex](x-6)^2 + (y-2)^2 = (y- 0)^{2}[/tex]
Expand the expression and bring all terms to one side
[tex]x^{2} - 6x - 6x + 36 +y^{2} -2y- 2y +4[/tex] = [tex]y^{2} - 0[/tex]
Collect like terms
[tex]x^{2} - 12x -4y + 40 = 0[/tex]
Make 'y' the subject of the formula
[tex]4y = x^{2} - 12x + 40[/tex]
Divide through by 4 and substrate 4 from 40 to give a perfect quadratic equation
[tex]y = 1/4( x^{2} - 12x + 36) + 4[/tex]
1/4 is dividing the quadratic equation [tex]x^2 - 12x +36[/tex]
Then divide factor by 4 to give 1, this is so because of the nature of the options given
[tex]y = 1/4( x^{2} -6x -6x +36) + 1[/tex]
Simplify the expanded quadratic equation
[tex]y = x (x -6) - 6 (x- 6)[/tex], we have [tex](x - 6) ^2[/tex]
Then insert in place into previous equation
[tex]y = 1/4 (x-6)^2 + 1[/tex]
Thus, the equation of the parabola is given as [tex]y = 1/4 (x-6)^2 +1[/tex]
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Help please help! Please help..
