Question 1
[tex]\text{pH}=-\log(\text{H}^{+})\\\\13=-\log(\text{H}^{+})\\ \\ \text{[H}^{+}]}=1 \times \boxed{10^{-13} \text{ moles per liter}} \\ \\ \text{[H}^{+}] \times \text{[OH}^{-}] =1 \times 10^{-14} \text{ M}\\\\\text{[OH}^{-}]=\boxed{1 \times 10^{-1} \text{ moles per liter}}[/tex]
Question 2
[tex]\text{pH}=-\log(\text{H}^{+})\\\\\text{pH}=-\log(1.0 \times 10^{-4})=\boxed{4}[/tex]
When did China's earliest civilization originate?
Answer:
The Chinese civilization really has an exact chronology, and the historical period began in the first year of the Western Zhou Dynasty in 841 BC. Before that, only the lineage records of the kings were recorded. Therefore, the earliest origin of Chinese civilization has not yet been finalized. Although there are many records about the Xia Dynasty in the traditional literature, due to the late completion of the book, there is no recognized evidence of the existence of the Xia Dynasty and its previous history. Therefore, some people in the modern and modern historical circles have always questioned the existence of the Xia Dynasty. sex.
Explanation:
Write and balance the equation for the combustion of the fatty acid lauric acid, (C12H24O2).
C12H24O2 +17 O2-------->12CO2 + 12H2O
Combustion:-
combustion is a chemical reaction that often involves the presence of oxygen and produces heat and light in the form of flames.
Lauric acid:-Lauric acid has a 12-carbon backbone and is a saturated medium-chain fatty acid. In addition to being a key component of coconut oil and palm kernel oil, lauric acid occurs naturally in a variety of plant and animal fats and oils.
White solid lauric acid has a little bay oil odour to it.
Lauric acid is a cheap, non-toxic, and easy-to-handle substance that is frequently employed in lab studies on melting-point depression. Because lauric acid is a solid at ambient temperature but a liquid at boiling temperatures, it can be used to test different solutes to determine their molecular weights.
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HELP!!! LOTS OF POINTS AND I GIVE BRIANLEST NO FAKE ANSWERS
Given the following data for water:
Heat of fusion = 334 J/g
Heat of vaporization = 2,256 J/g
Specific heat of solid = 2.09 J/(g °C)
Specific heat of liquid = 4.184 J/(g °C)
Specific heat of gas = 1.84 J/(g °C)
Calculate how much energy is needed to change 50.0 grams of ice at −15.0 °C to liquid water at 50.0 °C. (3 points)
a
11,900 J
b
16,300 J
c
18,300 J
d
21,100 J
Answer:
18300 J
Explanation:
this is because the amount of energy can be changed
Explain why the compound Cl2O has a low melting and boiling point.
In a recent study, 50 males used a new weight-loss supplement, and 37 of them experienced weight loss after two weeks: In the same study, 20 females used
the same supplement, and 13 of them experienced weight loss after two weeks.
Fill in the blanks below to make the most reasonable statement possible.
The new weight-loss supplement was less effective on (Choose one) in the study. That is because only % of them lost
weight after two weeks, whereas % of the (Choose one) lost weight after two weeks.
Answer:
The new weight-loss supplement was less effective on females in the study. That is because only 65% of them lost weight after two weeks, whereas 74% of the males lost weight after two weeks.
Explanation:
37 out of 50 males lost weight after two weeks, so 74% of males lost weight ( (37 · 2)/(50 · 2) ). 13 out of 20 females lost weight after two weeks, so 65% of females lost weight ( (13 · 5)/(20 · 5) ). This means the supplement was less effective on females because males had a higher percentage of losing weight.
Hope this helps !! :D
What is the mole fraction of NaBr in
an aqueous solution that contains
20.1% NaBr (weight/weight %)?
Molar Mass
NaBr: 102.89 g/mol
H₂O: 18.016 g/mol
Enter text here
Answer:
4.22% NaBr
Explanation:
To find the mole fraction of NaBr, you need to (1) determine the mass of the solute (NaBr) and the solvent (H₂O), then (2) convert the mass of the solute and solvent to moles (via the molar masses), and then (3) calculate the mole fraction of NaBr. The final answer should have 3 sig figs to match the sig figs of the given value (20.1%). Because you are given a percent less than 100%, you can assume that the percent (20.1%) is equal to the mass of the solute (20.1 g).
(Step 1)
100% - 20.1 % NaBr = 79.9% H₂O
20.1% NaBr = 20.1 g NaBr
79.9% H₂O = 79.9 g H₂O
(Step 2)
Molar Mass (NaBr): 102.89 g/mol
20.1 g NaBr 1 mole
------------------- x --------------------- = 0.195 mole NaBr
102.89 g
Molar Mass (H₂O): 18.016 g/mol
79.9 g H₂O 1 mole
------------------ x ------------------- = 4.43 moles H₂O
18.016 g
(Step 3)
moles of solute
Mole Fraction = ---------------------------------------------------- x 100%
moles of solute + moles of solvent
0.195 mole NaBr
Mole Fraction = -------------------------------------------------------- x 100%
(0.195 mole NaBr) + (4.43 moles H₂O)
Mole Fraction = 4.22% NaBr
Answer:
0.0422
Explanation:
Right on Acellus
Design a controlled experiment to test your hypothesis. A controlled experiment is one that only tests one variable. All other variables must remain the same. Make a drawing below that shows how you will set up your experiment. Then, write a description of the one factor that will vary and the two factors that will remain the same.
The problem is not found here but a possible experiment might be to measure the amount of product from a chemical reaction.
What is an experiment?An experiment is a procedure used to verify a working hypothesis obtained by applying the scientific method.
Experimental variables that can be tested include, for example, temperature, amount of product from a chemical reaction, etc.
In conclusion, the problem is not found here but a possible experiment might be to measure the amount of product from a chemical reaction.
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what is the name of this compound?
The compound above is a cyclic (ring) compound.
What are organic compounds?Organic compounds are compounds which contains carbon and hydrogen.
Some classes of organic compounds include the following:
AlkanesAlkenesAlkynesAkanolsAlkanonesEstersKetonesAminesSo therefore, the compound above is a cyclic (ring) compound.
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Which of the following industries is leaching used in?
To separate a metal from its ore using acid and preserving desirable products such as gold.
To separate a mixture of ethanol and water
To separate a slurry containing chalk and water
None of the above.
Answer:
To separate a metal from its ore using acid and preserving desirable products such as gold.
Explanation:
please make brainiest
Which sequence represents the relationship between temperature and volume as explained by the kinetic-molecular
theory?
higher temperature → less kinetic energy
higher temperature → more kinetic energy→more space between particles → higher volume
less space between particles → higher volume
higher temperature → more kinetic energy less space between particles → lower volume
higher temperature → less kinetic energy→more space between particles lower volume
The correct sequence is higher temperature→ more kinetic energy→ more space between particles→ higher volume.
According to the postulates of Kinetic gas theory:
Postulate 1: It states that the average kinetic energy of gas particles is proportional to the absolute temperature of the gas.
Which states that the higher temperature, the higher the kinetic energy of the molecules, which is the start of the sequence of the relationship between temperature and volume.
Postulate 2: Average kinetic energy is proportional to the square of the speed, it shows that at higher the kinetic energy the faster the molecules will move.
Postulate 3: As the particles move faster, the particles will collide more frequently so they will move away from each other, occupying more space.
Postulate 4: More space between the molecules results in more volume.
So, the complete and correct sequence is higher temperature → higher kinetic energy (higher speed) → more space → more volume.
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What are oil traps?
Answer:
A device in which oil can be trapped, or which makes use of oil to trap something else I think
Help pls need it!:))
Answer:
[tex]\textsf {A}[/tex]
Explanation:
[tex]\textsf {The effect of a catalyst on the energy of a reaction system }\\\textbf {is that it reduces the activation energy.}[/tex]
Answer:
it reduces the activation energy (option A)
Explanation:
we know that a catalyst reduces the activation energy because it speeds up a reaction (that is what a catalyst is--a substance that speeds up a reaction [whilst leaving it unchanged chemically]. )
So, if a catalyst is speeding up the time it takes for a reaction to occur, it is logically lowering the minimum energy that is needed for the reaction to occur.
This can best be expressed in option A, because it lowers the activation energy
Polyester and Nylon are examples of synthetic materials called polymers.
A. True
B. False
Answer:
true is correct
Polyester and Nylon are examples of synthetic materials called polymers. This statement is True.
Polymers are large molecules composed of repeating subunits called monomers, which are chemically bonded together. In the case of polyester, it is made from a polymer called polyethylene terephthalate (PET), while Nylon is made from polyamide monomers. These polymers are created through polymerization processes that combine smaller molecules to form long chains.
Synthetic polymers like polyester and nylon are widely used in various applications due to their desirable properties, such as strength, durability, and resistance to chemicals and moisture.
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Three students are given a 200g object to weigh on a balance and record the following masses: 150g, 151g 150g. What can be said about the accuracy and precision of the balance?
Describe the subatomic structure of the nucleus, including the structure of each nucleon. Draw a picture. Describe the forces that hold the nucleus together and draw them on your diagram. Explain how beta emission works.
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Balanced chemical equation: BaCl2(aq)+Na2SO4(aq)⟶BaSO4(s)+2NaCl(aq)
Using 1.46 moles of NaCl, determine how many grams of NaCl can be produced.
Then, using the moles of NaCl found in a previous question, determine how many formula units of NaCl can be produced. formula units:
Answer:
Part 1) 85.3 grams NaCl
Part 2) 8.79 x 10²³ formula units NaCl
Explanation:
(Part 1)
To find the mass of NaCl, you need to multiply the given value (1.46 moles) by the molar mass of NaCl. This measurement is the atomic masses of the elements times each of their quantities combined. In this case, there is only one mole of each element in the molecule. Moles should be located in the denominator of the conversion to allow for the cancellation of units. The final answer should have 3 sig figs to reflect the given value.
Molar Mass (NaCl): 22.99 g/mol + 35.45 g/mol
Molar Mass (NaCl): 58.44 g/mol
1.46 moles NaCl 58.44 g
--------------------------- x ---------------- = 85.3 grams NaCl
1 mole
(Part 2)
I do not know which other question the second part is referring to, so I will just use the moles given in the first part. To find the formula units, you need to multiply the given value (1.46 moles NaCl) by Avogadro's Number. This conversion represents the number of formula units found in 1 mole of the sample. The moles should be in the denominator of the conversion to allow for the cancellation of units.
Avogadro's Number:
1 mole = 6.022 x 10²³ formula units
1.46 moles NaCl 6.022 x 10²³ units
------------------------ x ----------------------------- = 8.79 x 10²³ formula units NaCl
1 mole
If you had 6 mol of oxygen and 12 mol of mercury, what would be the limiting reactant? show your work
The limiting reactant between the reaction of 6 moles of oxygen and 12 moles of mercury is mercury (Hg)
Balanced equation4Hg + O₂ —> 2Hg₂O
From the balanced equation above,
4 moles of Hg reacted with 1 mole of O₂
How to determine the limiting reactantFrom the balanced equation above,
4 moles of Hg reacted with 1 mole of O₂
Therefore,
12 moles of Hg will react with = 12 / 4 = 3 moles of O₂
From the above calculation, we can see that only 3 moles of O₂ out of 6 moles given is required to react completely with 12 moles of Hg.
Thus, Hg is the limiting reactant and O₂ is the excess reactant .
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How many moles are in a gas with a temperature of 21°C, pressure of 1,351 mmHg and a volume of 2,000 mL
Answer:
.147 moles
Explanation:
PV = n RT choose the correct "R" to be 62.364 L torr /(K-mol)
T needs to be in K (so add 273.15)
1351 torr * 2 L = n * 62.364 * (21 + 273.15 )
solve for n = .147 moles
what are the condition for a gas like carbon (II) oxide to obey the gas laws?
Answer:
I don't know the answer, but I can give options :)
Explanation:
A gas such as carbon monoxide would be most likely to obey the ideal gas law at:
Option 1) High temperatures and low pressure.
Option 2) Low temperatures and high pressure.
Option 3) High temperatures and high pressure.
Option 4) Low temperatures and low pressure.
Answer:
The gas must occupy 0 volume at -273°celcius
What is one advantage of wind and hydroelectric power?
A. They are effective in any type of environment.
B. Neither harms wildlife.
C. Neither produces pollutants.
D. Both are inexpensive.
What is one advantage of wind and hydroelectric power?
A. They are effective in any type of environment.
B. Neither harms wildlife.
C. Neither produces pollutants.
D. Both are inexpensive.
Explanation:
one of the qnswer is flood control, irrigation support, and clean drinking water
The velocity is ___ when the distance is kept the same and the time is halved
Answer:
Velocity = distance / time
if distance is same and time is 1/2
Velocity = distance / time/2
velocity = 2 (distance /time)
Velocity,= 2 * velocity
Velocity will be doubled
Franklin Roosevelt promised the American people a "new deal," a pledge he made actually before he was elected, at the Democratic National Convention in 1932.
The New Deal program was to help the American economy recover from the Great Depression.
Who was Franklin Roosevelt?Franklin Delano Roosevelt was an American politician and attorney who served as the 32nd president of the United States from 1933 until his death in 1945.
Roosevelt promised the American people a "New Deal" if he was elected president in 1932. The goal of this New Deal program was to help the American economy to recover from the Great Depression.
Roosevelt's deal was based on providing economic relief to citizens, reforming institutions that failed during the early 1930's, and helping the overall economy to recover. This popular program lead FDR to be elected president 4 times.
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elemental phosphorus occurs as tetratomic molecules, p4. What mass in grams of chlorine gas is need to react completely with 455g of phosphorus to form phosphorus pentachloride?
P₄ + 10Cl₂ → 4PCl₅
mol P₄ = 455 : 123.895 g/mol = 3.672
mol Cl₂ = 10 x 3.672 = 36.72
mass Cl₂ = 36.72 x 71 g/mol = 2607.12 g
Sunspot populations quickly rise and more slowly fall on an irregular cycle about every 11 years. Significant variations of the 11-year period are known over longer spans of time. For example, from 1900 to the 1960s the solar maxima (the period of greatest activity in the solar cycle of the sun) trend of sunspot count has been upward; from the 1960s to the present, it has diminished somewhat. The Sun is presently at a markedly heightened level of sunspot activity and was last similarly active over 8,000 years ago.
The number of sunspots correlates with the intensity of solar radiation over the period (since 1979) when satellite measurements of absolute radiative flux were available. Since sunspots are darker than the surrounding photosphere it might be expected that more sunspots would lead to less solar radiation and a decreased solar constant. However, the surrounding margins of sunspots are hotter than the average, and so are brighter; overall, more sunspots increase the sun's solar constant or brightness. During the Maunder Minimum in the 17th Century there were hardly any sunspots at all. The Maunder Minimum is the name given to the period roughly from 1645 to 1715, when sunspots became exceedingly rare, as noted by solar observers of the time. It is named after the solar astronomer Edward W. Maunder (1851-1928) who discovered the dearth of sunspots during that period by studying records from those years. During one 30-year period within the Maunder Minimum, for example, astronomers observed only about 50 sunspots, as opposed to a more typical 40,000-50,000 spots. This coincides with a period of cooling known as the Little Ice Age.
1) Which of the following is a true statement?:
A. There were more sunspots in 1965 than in 1701
B. The Little Ice Age had nothing to do with sunspots
C. The Sun is presently at a low level of sunspot activity
D. No one is counting sunspot activity any more
The Sun is presently at a low level of sunspot activity. Hence, option C is correct.
What is solar radiation?Solar radiation is often called the solar resource for the electromagnetic radiation emitted by the sun.
The Sun is presently at a low level of sunspot activity is the correct answer.
Hence, option C is correct.
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Question 5 of 10
Platinum has a density of 21 g/cm³. A platinum ring is placed in a graduated
cylinder that contains water. The water level rises from 4.0 mL to 4.2 mL
when the ring is added. What is the mass of the ring?
A. 2.6 g
OB. 3.8 g
OC. 4.2 g
OD. 5.2 g
B
Answer:
4.2 g
Explanation:
The VOLUME of the ring is 4.2 - 4.0 = .2 ml = .2 cm^3
the MASS of the ring is this times the density
.2 cm^3 * 21 g/cm^3 = 4.2 g
Answer:
the answer is c
Explanation:
density is mass/volume
so mass=density × volume
but we take the change is volume that is v2-v2=4.2-4=0.2ml
but the density is in gm/cm^3 so we should convert ml into cm^3. eventually they are equal so mass=21×0.2=4.2
The equilibrium constant for the reaction 2 C3H6(g) ↔ C2H4(g) + C4H8(g) Is found to fit the expression: lnK = A + B/T + C/T2, between 300 and 600 K, where A = -1.04, B = -1088 K, C = 1.51x105 K2. Calculate the standard reaction enthalpy and standard reaction entropy at 400 K.
The standard reaction enthalpy and the standard reaction enthalpy at 400 K for this reaction are equal to 0.35 kJ and 0.000125 kJ respectively.
How to calculate Gibbs's free energy?Mathematically, the Gibbs's free energy for this chemical reaction can be calculated by using this formula:
ΔG° = -RTlnK = ΔH° - TΔS° ......equation 1.
First of all, we would determine the value of lnK from the given expression at 390 K and 410 K respectively:
lnK = A + B/T + C/T²
lnK = -1.04 - 1088/T + 1.51 × 10⁵/T²
lnK = -1.04 - 1088/390 + 1.51 × 10⁵/390²
lnK = -1.04 - 2.79 + 0.99
lnK = -2.84.
At T = 410 K, we have:
lnK' = -1.04 - 1088/410 + 1.51 × 10⁵/410²
lnK' = -1.04 - 2.65 + 0.90
lnK' = -2.79.
For the standard reaction enthalpy, we have:
lnK' - lnK = ΔH°/R(1/T - 1/T')
-2.79 - (-2.84) = ΔH°/8.314(1/390 - 1/410)
-2.79 + 2.84 = ΔH°/8.314(0.00256 - 0.00244)
0.05 = ΔH°/8.314(0.0012)
0.4157 = 0.0012ΔH°
ΔH° = 0.4157/0.0012
ΔH° = 346.42 ≈ 0.35 kJ.
Next, we would determine the Gibbs's free energy at each temperature:
At T = 390 K, we have:
ΔG° = -RTlnK
Δ₁G° = -8.314 × 390 × (-2.84)
Δ₁G° = 9.21 kJ/mol.
At T = 410 K, we have:
Δ₂G° = -8.314 × 410 × 2.79
Δ₂G° = 9.51 kJ/mol.
For the standard reaction enthalpy at 400 K, we have:
ΔG° = ΔH° - TΔS°
9.51 - 9.21 = 0.35 - 400ΔS°
0.30 = 0.35 - 400ΔS°
400ΔS° = 0.35 - 0.30
400ΔS° = 0.05
ΔS° = 0.05/400
ΔS° = 0.000125 kJ.
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Which of the following is a simple design model that uses the concepts define, optimize, and develop solutions iteratively and in any order?
A. Infused Design
B. FORFLOW
C. Munich Procedural Model
D. Next Generation Design Model
The Munich Procedural Model is a simple design model that uses the concepts define, optimize, and develop solutions iteratively and in any order. C
What is the Munich procedural design?The Munich procedural model is a design that illustrates several opportunities regarding the order in which design process and stages beyond mere iteration should take.
A procedural model commonly used for development is the V-model.
Hence, the Munich Procedural Model is a simple design model that uses the concepts define, optimize, and develop solutions iteratively and in any order.
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How many significant figures does 7,874.9640 s have?
Submit Question
Answer:
8 significant figures
Explanation:
All numbers (that are not zero) are always significant. Because there is a zero at the end of the number after the decimal place, this makes this zero also significant. This zero is significant because it makes the number more precise. Therefore, all of the numbers in this number are significant.
Answer:
There are 8 sig figs
Explanation:
4HCl(g)+O2(g)⟶2Cl2(g)+2H2O(g) Calculate the number of grams of Cl2 formed when 0.385 mol HCl reacts with an excess of O2. mass: g
The number of grams of Cl2 formed when 0.385 mol HCl reacts with an excess of O2 is 13.6675 g.
What are moles?A mole is defined as 6.02214076 × [tex]10^{23}[/tex] of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
Given data:
Moles of hydrochloric acid = 0.385 mol
Mass of chlorine gas =?
Chemical equation:
4HCl + O₂ → 2Cl₂ + 2H₂O
Now we will compare the moles of Cl₂ with HCl.
HCl : Cl₂
4 : 2
0.385 : 2÷4× 0.385 = 0.1925 mol
Oxygen is present in excess that's why the mass of chlorine produced depends upon the available amount of HCl.
Mass of Cl₂ :
Mass of Cl₂ = moles × molar mass
Mass of Cl₂ =0.1925 mol × 71 g/mol
Mass of Cl₂ = 13.6675 g
Hence, the number of grams of Cl2 formed when 0.385 mol HCl reacts with an excess of O2 is 13.6675 g.
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At ground level, how are rain and hail similar?
They are forms of water in its liquid state.
They occur when the temperature is below freezing.
They can occur when the air is hot and moist.
They are most common in the winter.
They are forms of water in its liquid state at ground level. Thus, the correct option is A.
What is hailstrom?Precipitation, or water in the atmosphere, forms hail. When water drops freeze together in the chilly higher parts of thunderstorm clouds, hail is the result.
When a water droplet is lifted by an updraft from a thunderstorm over the freezing point of the atmosphere, hail is created. The super-cooled water or water vapor that the frozen water droplet accretes later freezes when it comes into touch with it. A hailstone grows as a result of this process.
When water vapor from the atmosphere condenses into liquid water droplets, they become heavy enough to fall as a result of gravity.
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Answer:A
Explanation:
.