Answer:
Hrxn = -241.82 kJ
Explanation:
2H2(g) + O2(g) --> 2H2O(g) Hrxn = -483.64 kJ ............. (i)
The equation for formation of 1 mol of H2O is given as;
H2(g) + 1/2O2(g) --> H2O(g) ................. (ii)
Eqn (ii) is obtained by dividing eqn (i) by 2
That means the heat of reaction for eqn (ii) is given as;
Hrxn = -483.64 kJ / 2
Hrxn = -241.82 kJ
Answer:-241.82 kJ
Explanation:
your welcome kaylee and have a great day ;)
When a 8 gram slice of bread is burned under a beaker of 4500 grams of water, it heats up the water by 1.3 degrees Celsius. The specific heat of water is 1 cal/g degree C. How many calories does this slice of bread contain
Answer:
[tex]5850\ \text{cal}[/tex]
Explanation:
m = Mass of water = 4500 g
c = Specific heat of water = [tex]1\ \text{cal/g}^{\circ}\text{C}[/tex]
[tex]\Delta T[/tex] = Change in temperature of water = [tex]1.3^{\circ}\text{C}[/tex]
Heat is given by
[tex]q=mc\Delta T\\\Rightarrow q=4500\times 1\times 1.3\\\Rightarrow q=5850\ \text{cal}[/tex]
A slice of the bread contains [tex]5850\ \text{cal}[/tex].
Which of the following is the chemical formula for an acid?
- NHO3 (aq)
- NaOH (aq)
- NH3 (g)
- HCl (g)
- SCl2 (g)
Why?
Answer:
NH3 and HCl
Explanation:
NH3 and HCl are acids because of their hydrogen ions. NHO3 and NaOH are bases (you can tell because they have an OH). I don't believe SCl2 is an acid or a base
the reaction 2F2+ 2H2O + 4HF + 02 find the number of moles of oxygen produced from 10 moles of fluorine
Answer:
20 moles of Oxygen
Explanation:
2F2 + 2H20 -> 4HF + O2
We have 10 moles of fluorine. Based on the reaction equation, we see that:
n O2 = 2 * n F2 (n is the number of moles)
=> n O2 = 2 * 10 = 20 (moles)
Because of this, the number of moles of oxygen is 20 moles.
If you divided one regtangle into ten smaller regtangles and then each of those into ten each of the smallest regtangles is?
Answer:
0.01.
Explanation:
This is because, if you divided one rectangle by ten, it will give 0.1
That is 1/10 = 0.1
If each of the smaller rectangles is divided by 10.
It will be 0.1/10 which will be equal to 0.01.
The rectangles will be 0.01 each.
HELP WITH THIS WORD PROBLEMStudents want to gather evidence for the claim that the number of atoms present before a chemical reaction is equal to the number of atoms present after the chemical reaction. They decide to react vinegar and baking soda in a sealed plastic bag. Which of the following would provide the evidence the students need?
The mass of the plastic bag, baking soda, and vinegar before the reaction was equal to the mass after the reaction.
Bubbles were produced during the reaction, which meant that a gas was being produced
.The plastic bag did not change in any way, indicating that it was not involved in the reaction.
The mass of the baking soda was exactly equal to the mass of the vinegar used to create the chemical reaction.
A closed gas system initially has volume and pressure of 6400mL and 1.49atm with the temperature unknown. If the same closed system has values of 657 torrs, 9660mL, and 2450C, what was the initial temperature in K?
Answer: The initial temperature was 588 Kelvin
Explanation:
The combined gas equation is,
[tex]\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]
where,
[tex]P_1[/tex] = initial pressure of gas = 1.49 atm
[tex]P_2[/tex] = final pressure of gas = 657 torr = 0.864 atm (760 torr = 1atm)
[tex]V_1[/tex] = initial volume of gas = 6400 ml
[tex]V_2[/tex] = final volume of gas = 9660 ml
[tex]T_1[/tex] = initial temperature of gas = ?
[tex]T_2[/tex] = final temperature of gas = [tex]245^0C=(245+273)K=515K[/tex]
Now put all the given values in the above equation, we get:
[tex]\frac{1.49\times 6400}{T_1}=\frac{0.864\times 9660}{515}[/tex]
[tex]T_1=588K[/tex]
The initial temperature was 588 Kelvin
40 points
I have 400 mL of a 0.2 M simple syrup solution (made up of just sugar and water) that I want to boil down to result in a solution with a concentration of 0.5 M. How many milliliters of water would I need to evaporate?
Answer:
2000ml
Explanation:
you multiple 400ml with 0.5 ml to get the required meter for the water that needs to be evaporated
answer pls ill give brainly
How is energy from the sun used as food energy by organisms in an ecosystem?
Energy from the sun is absorbed as heat by consumers.
Energy from the sun is absorbed by fungi, and it is then passed on to consumers.
Energy from the sun is converted into food energy by producers, which is then passed on to consumers.
Energy from the sun is converted into food by consumers, which is then passed on to producers.
Answer:
its absorbed by heat from consumers
Science question: Which beat summarized the scientific process that led to our current understanding of DNA?
1 each scientist made an important but unrelated contribution
2. Scientists built on the previous work of other scientists to make new discoveries
3 and 4 are too long
Answer:
2
Explanation:
in terms of cells, it exists from previous existing cells, that means scientist are built up by the work of other scientist
Answer:
the answer is B
Explanation:
write an ionic half equation for the formation of hydrogen during this electrolysis
Answer:
A half-equation shows you what happens at one of the electrodes during electrolysis. Electrons are shown as e-. A half-equation is balanced by adding, or taking away, a number of electrons equal to the total number of charges on the ions in the equation.
When positive metal ions (cations) arrive at the negative electrode (the cathode), they gain electrons to form neutral metal atoms. This is called reduction. For example:
Pb2+ + 2e- → Pb
When negative non-metal ions (anions) arrive at the positive electrode (the anode), they lose electrons to form neutral atoms or molecules. This is called oxidation. For example:
2Br- → Br2 + 2e-
Writing half equations
Cations go to the cathode. They need to gain enough electrons to make them neutral. So an Al3+ ion needs to gain three electrons:
Al3+ + 3e- → Al
Half-equations for non-metal anions are more difficult to balance. For example, chloride ions make chlorine gas. Most non-metal elements formed in electrolysis are diatomic molecules (eg Cl2). For example:
Cl- → Cl2
Add in two electrons to balance the charge so that both sides have the same charge. The two electrons need to go on the right-hand side, so that both sides have an overall charge of -2. For example:
2Cl- → Cl2 + 2e-
Although your question lacks some information a general answer is provided
The ionic half equation = [tex]2H^{+} (aq) + 2e^{-} ----> H_{2} (g)[/tex]
The formation of hydrogen takes place at the negative electrode in a cell and the ionic half reaction that shows the formation of the hydrogen gas at the electrode is written as :
[tex]2H^{+} (aq) + 2e^{-} ----> H_{2} (g)[/tex]
Ionic half equation is the representation of the chemical activity ( reaction ) occurring at one of the electrodes of a cell. to balance a half reaction we add or remove electrons equal to charges on the ions.
Hence the Ionic half equation for the formation of hydrogen during electrolysis is written as ; [tex]2H^{+} (aq) + 2e^{-} ----> H_{2} (g)[/tex]
learn more : https://brainly.com/question/4046381
What are ancient plants and animal formed into rocks called it is a 7 letter word that starts with f
Answer:
Fossils
Explanation:
Ancient plants and animal formed into rocks called fossils.
A fossil can be defined as the mineral impression or remains of living organisms such as plants and animals that are prehistoric in nature.
A geologic column can be defined as a collection of rock layers that are typically grouped based on their relative ages in a descending order i.e from oldest to the youngest.
Generally, the layers of the rock that are found in various parts of the world are known to be different because they all comprises of distinct Earth's geological history (fossils).
Calculate the molarity of a solution containing 21.9g of MgCl, in enough water to
make a 750.mL solution.
11.
Which of these statements is true about the two graphed parallelograms?
A
B
8
6
A
4
B'
D
C
2
D
C'
-6
2
4
6
-2.
-2
-4
-6
-8 +
A
They are similar, because one can be obtained by dilating the other about the origin with a scale factor of
Answer:
Explanation:
dfghyuiop[]5565677dam u baddie no comparing
What challenges or opposition did Galileo face in having his theories accepted and why
Answer:
Poorness is the one because he needs large money for his inventions and tools to use in them. He also have problems in securing patent protection and dealing with publishing pressure.
But the greatest problems is the opposition of his discoveries by the Catholic Church, they banned his books, they abstain him from teaching inventing, and writing. But as we know, a hero stands even on the hardest times
Explanation:
The challenges or opposition to Galileo Galilei, an astronomer, and mathematician, struggled with issues that contemporary scientists would recognize, such as obtaining funding, acquiring patent protection, and coping with the urge to publish.
Who was Galileo?Galileo was an astronomer and scientist. He was from Italy. He is a famous scientist and did many discoveries in the field of astronomy. The main discoveries were craters and mountains on the moon and the stars of the galaxy.
He was criticized for believing in the kinetic hypothesis, and he denied astronomical authority. The challenges he faced were patent problems and funding problems.
Thus, Galileo was criticized for defending the kinetic hypothesis and denying the astronomical authority of Scripture.
To learn more about Galileo, refer to the link:
https://brainly.com/question/14490755
#SPJ2
please help!! will give brainliest if u tell me how
Why does heat transfer from object to object?
Select one:
a.Heat transfers because of the temperature differences between objects
b.Heat transfers because of the mass difference between objects
c.Heat does not transfer between objects
d.Heat is energy so it moves
Help please
what is the half-life of c-14 at 250g?
Answer:
5,730 years
hope im right
Explanation:
Its half-life is 5,730 years. How much of a 250g sample of carbon-14 will be left in 5,000 years?
write the electronic configuration of an Na+ and CL-1
Answer:
Na+ lost one electron: 1s2 2s2 2p6
Cl- gained an electron: 1s2 2s2 2p6 3s2 3p6
Explanation:
Mechanism of aspirin by salicyclic acid reacts with acetic acid ? Mechanism of benzoic acid from benzamide?
Answer:
See explanation
Explanation:
The synthesis of aspirin is shown in the reaction scheme attached to this answer. The production of aspirin involves the reaction of acetyl salicyclic acid and acetic anhydride. HA in the reaction mechanism refers to an acid that is used in the reaction
Similarly benzamide, is converted to the carbonyl carbocation by reaction with acid. The -NH2 group is protonated and subsequently departs as a leaving group. An OH^- completes the mechanism forming a carboxylic acid. The movement of electrons is shown in the image attached.
Again, the diazotization of benzamide using sodium nitrate and concentrated HCl yields benzene diazonium chloride. Addition of water to benzene diazonium chloride yields the benzoic acid and nitrogen gas.
2 NH3(g) → N2(g) + 3 H2(g)
What type of reaction is shown above?
A)
single replacement
B)
decomposition
C)
double replacement
D)
synthesis
Answer:
Decomposition Reaction
Explanation:
In the provided reaction, we can see that Ammonia is getting decomposed into Nitrogen and Hydrogen gas.
Another way to think about it is that Decomposition is nothing but one thing giving rise to 2 or more than 2 things.
Since our Ammonia is giving rise to 2 gases, this reaction is an example of Decomposition reaction
What is the independent
variable in this lab?
temperature
distance
thermal conductivity
time
specific heat
Answer:
time
Explanation:
time can be controlled and set while all the others can't be necessarily controlled
A teacher tells the student to dlaw the same wave with double the frequency, while keeping the amplitude the same. How would the student draw the new wave?
Answer:
A.
Explanation:
Frequency is how often one complete cycle or wave takes place. Amplitude is the height of the wave from the midpoint to the crest.
The new drawing should have twice as many waves in the same period of time, with the same height wave.
Answer:
A.)
Explanation:
Frequency is how often one complete cycle or wave takes place. Amplitude is the height of the wave from the midpoint to the crest.
The new drawing should have twice as many waves in the same period of time, with the same height wave.
Water conservation is important for which of the following reasons?
A. Demand for water is increasing.
B. Water treatment is expensive.
C. Pollution is likely to decrease water supply in the future.
D. All of the above
D
all of above becuase it's all conservation
Answer:
The answer is c which is pollution is likely to decrease water supply in the future
(I ONLY HAVE 15 MIN LEFT IN MY TEST PLEASE HELP ME!!)
If 107 g of a substance reacts with 76 g of another substance, what will be the mass of the products after the reaction
Answer:
183g
Explanation:
mass can't be created or destroyed so i think you just add up the total amounts of matter
1. Which of the five types of reactions is taking place in the whoosh bottle? Justify your answer with evidence from the video.
Answer:
Other times I place a candle in water and cover it with a glass jar .
Explanation:
only to ... Many of you may already know this as the Whoosh Bottle demo due ... I have used this demo in the past for topics like exothermic reactions, combustion reactions, ... This adds to the evidence of a partial vacuum created in the bottle
In a warehouse, the workers sometimes slide boxes along the floor to move them. Two boxes were sliding toward each other and crashed. The crash caused both boxes to change speed. Based on the information in the diagram, which statement is correct? In your answer, explain what the forces were like and why the boxes changed speed.
Box 1 has more mass than Box 2.
Box 1 and Box 2 are the same mass.
Box 1 has less mass than Box 2.
Answer:
Box 1 and Box 2 are the same mass.
Explanation:
Because they both change speed due to having the same mass!
Hope this helps! :) BRAINLIEST PLZ
Is the fractional distillation of liquefied air a physical or chemical change?
Answer:
Physical Chanhe is the answer : )
The freezing point of pure water is 0 °C (32 °F). How do you think adding salt to water affects its freezing point?
Give me lil reasoning so I know your not lying for points
:(
(I’ll mark you as brainlister )
Answer:
C
Explanation:
An inverse relationship means that as one increases the other decreases. From the negative slope of this graph, you can tell that as volume increases, pressure decreases. If you look at the data point for 20 on the volume axis, it matches up with about 240 on the pressure axis.
how do i make chrystals
Answer:
1. In the beaker, stir 1/2 cup of Epsom salts with 1/2 cup of very hot tap water for at least one minute. ...
2. Add a couple drops of food coloring if you want your crystals to be colored.
3. Put the beaker in the refrigerator.
4. Check on it in a few hours to see a beaker full of epsom salt crystals!
Explanation:
Calculate the change in heat (Q) that occurs when 7.58grams of steam at 101°C cools to liquid water at 40°C. (cp = 4.184 J/g°C)
Answer:
Q = 19065.4 J
Explanation:
Q₁ = the required energy for phase change of H₂O from vapor to liquid
Q₁ = mass of H₂O * heat of vaporization
Q₁ = 7.58 g * 2260 J/g
Q₁ = 17130.8 J
Q₂ = energy required to cool the water fro 101°C to 40°C
Q₂ = mass of H₂O * specific heat of H₂O * ΔT
Q₂ = 7.58 × (4.184 J/gC) × (101 - 40)
Q₂ = 1934.6 J
Q = Q₁ + Q₂
Q = (17130.8 + 1934.6) J
Q = 19065.4 J