The enthalpy tell us about the heat that may be absorbed or evolved in a reaction. The ethalpy of this reaction is -100 kJ/mol.
What is enthalpy?The term enthalpy deals with the heat that is absorbed or emitted in a reaction. The reaction equation is; HNO3 + KOH ----> KNO3 + H2O
Number of moles of HNO3 = 0.5 M * 50/1000 L = 0.025 moles
Number of moles of KOH= 0.5 M * 50/1000 L = 0.025 moles
Since the reaction is 1:1, then heat evolved = - (2500 J * 10^-3)/0.025 moles
= -100 kJ/mol
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Ethanoic acid has a pKa of 4.75. Find the pH of the solutions that results from the addition of 40.0 mL of 0.040 M NaOH to 50.0 mL of 0.075 M ethanoic acid.
Answer:
About 4.63.
Explanation:
The reaction between ethanoic acid (CH₃COOH) and sodium hydroxide (NaOH) can be described by the following net ionic equation:
[tex]\displaystyle \text{CH$_3$COOH}_\text{(aq)} + \text{OH}^-_\text{(aq)}\longrightarrow \text{CH$_3$COO}^-_\text{(aq)} + \text{H$_2$O}_\text{($\ell$)}[/tex]
40.0 mL of 0.040 M NaOH contains:
[tex]\displaystyle 40.0\text{ mL} \cdot \frac{0.040\text{ mol NaOH}}{1000\text{ mL}} = 0.0016\text{ mol NaOH}[/tex]
Because NaOH is a strong base, it dissociates completely. Hence, the amount of OH⁻ present is 0.0016 mol. Na⁺ acts as a spectator ion.
50.0 mL of 0.075 M CH₃COOH contains:
[tex]\displaystyle 50.0\text{ mL} \cdot \frac{0.075\text{ mol CH$_3$COOH}}{1000\text{ mL}} = 0.0038\text{ mol CH$_3$COOH}[/tex]
OH⁻ is the limiting reagent of the reaction. Therefore, as the reaction proceeds to completion:
The amount of OH⁻ drops to 0 mol. The amount of CH₃COOH decreases to (0.0038 - 0.0016) mol = 0.0022 mol. And the amount of CH₃COO⁻ increases to (0 + 0.0016) mol = 0.0016 mol.Note that all species present are in a one-to-one ratio.
To find pH, we can use the Henderson-Hasselbalch equation:
[tex]\displaystyle \text{pH} = \text{p}K_a + \log\frac{[\text{Base}]}{[\text{Acid}]}[/tex]
The total volume of the solution is 40.0 mL + 50.0 mL = 90.0 mL.
Hence, find [CH₃COOH]:
[tex]\displaystyle \left[\text{CH$_3$COOH}\right] = \frac{0.0022\text{ mol}}{90.0\text{ mL}} \cdot \frac{1000\text{ mL}}{1\text{ L}} = 0.024\text{ L}[/tex]
Find [CH₃COO⁻]:
[tex]\displaystyle \left[\text{CH$_3$COO}^-\right] = \frac{0.0016\text{ mol}}{90.0\text{ mL}}\cdot \frac{1000\text{ mL}}{1\text{ L}} = 0.018\text{ M}[/tex]
Therefore, the pH of the resulting solution is:
[tex]\displaystyle \begin{aligned}\text{pH} & = \text{p}K_a + \log\frac{[\text{Base}]}{[\text{Acid}]} \\ \\ & = (4.75) + \log \frac{(0.018)}{(0.024)} \\ \\ & = 4.75 + (-0.12) \\ \\ & = 4.63\end{aligned}[/tex]
In conclusion, the pH of the resulting solution is about 4.63.
Wildfires displace many animals and leave behind ash and soot-covered habitats for the animals that
survive. If a wildfire
occurred in the Everglades, which insect would be the
most likely to survive
predators in an ash and soot-covered habitat? (SC.5.L. 15.1)
A. Red dragonfly
B. Green grasshopper
C. Brightly colored butterfly
D. Gray-colored speckled moth
7. A group of students is using models to explore the relationship between the shape of a bird's beak
the type of food it eats. The students design an investigation using classroom items as beaks. Each
If a wildfire occurred in the Everglades, the insect which most likely to survive predator is gray-colored speckled moth.
What are predators?Predators are those animals which for their survival will hunt or kill another animals for the fulfilment of their food need.
If wildfire occured in the everglades region then the insect would be the most likely to survive predators in an ash and soot covered habitat is gray-colored speckled moth which is also known as darwin moth as it takes part in evolution of natural process.
Hnece the required animal is gray-colored speckled moth.
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A student observes the phenomenon where a straw has a different appearance when placed in water. Once this was noted by the student, they then immediately thought about why they have been unable to successfully catch fish when spearing them in the water. Relate these two phenomenon and select ALL statements that apply to the phenomena described here.
A)The water distorts the image of the fish so that its image is inverted.
B)The student is not aiming correctly due to refraction of the fish in the water.
C)The water magnifies the image, making the target fish look bigger than it actually is.
D)The light waves travel at a different speed in water and make the fish appear farther away.
E)The diffraction of the light around objects flips the image from left to right, making aiming for fish more of a challenge.
Answers are B and D
Answer:
b, and d
Explanation:
if the student did not aim correctly, and for d if the light waves travelled differently
Step 1: Pick your favorite physical activity This can be almost anything! Try to pick an activity that you like to participate in, but you can pick anything you want. It could be hockey, tennis, wakeboarding, dancing, rock climbing, or even walking your dog! Almost ANY activity will work for this assignment. Step 2: Research the activity Get on the internet and learn about the activity you selected. Step 3: Write a brief report - 2 full paragraphs Be sure to include the following information in your report: - What activity you selected and why you selected it. - 2 health benefits of your activity. - 3 different muscles that your activity uses or "works out." - If participating in your activity presents any safety concerns. When you have finished your 2 full paragraphs, submit your assignment here!
Dancing is a physical activity which strengthens the abdominal and calf muscles as well as improves flexibility.
What is a physical activity?A physical activity is any activity which involves movement of the body in order to strengthen the muscles and to be physically fit.
Dancing is a physical activity which involves intricate and repeated movements of the body.
Dancing is beneficial because;
it helps to relieve stress it improves flexibility it builds muscle enduranceSome muscles involved in dancing include;
The abdominal muscles The quadricepsthe glutesSome risks in dancing include muscle injuries, dislocations and possibly fractures due to falls.
Therefore, a dancing routine strengthens the abdominal and calf muscles as well as improves flexibility.
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HELP ME OUT PLS!!!!!!!!!
All stars begin their life in a
O black hole
O main sequence
O protostar
O nebula
nebula
↪ExplanationAll stars start in a large cloud of dust and gas called a nebula. Gravity can pull some of the gas and dust in a nebula together, forming a proto-star. A star is born when the gas and dust from a nebula become so hot and dense that hydrogen atoms are smashed together to form helium.
hope this helps...
10 POINTS!
What stops beta particles?
skin
aluminum foil
paper
air
Answer:
The answer is aluminum foil.
Answer:
aluminum foil Mark me brainliest, please.The picture shows the cubic unit cell of CaF2. How many Ca2+ ions and F- ions are present in the cubic unit cell?
The total number of Ca2+ ions and F- ions that are present in the cubic unit cell will be 4 and 8 respectively.
How to calculate the unit cell?From the complete information, the number of Ca2+ at corners will be (8 × 1/8 = 1) and those a the center will be (6 × 1/2 = 3). Therefore, the total number of Ca2+ will be:
= 1 + 3 = 4
The total number of F- ions will be:
= 4 × 2 = 8
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Which of the following compounds will have the lowest molar solubility in pure water?
a-AgBrO3, Ksp = 5.38 x 10-5
b-MnCO3, Ksp = 2.24 x 10-11
c-Hgs, Ksp = 1.60 x 10-54
d-Zns, Ksp = 2.00 x 10-25
e-SrS04, Ksp = 3.44 x 10-7
Answer:
C
Explanation:
It has the lowest Ksp, so it will have the lowest Molar Solubility
Without conducting an experiment, how could you predict if a species in a solution is acidic or basic? Give some examples.
Without conducting an experiment, one can determine if a species in a solution is acidic or basic by using a litmus paper.
Litmus testAcidic species would turn a blue litmus paper to red but have no effects on red litmus paper.
Basic species would turn a red litmus paper to blues but have no effects on blue litmus paper.
Thus, in order to determine if a species in a solution is acidic or basic without conducting any experiment, dipping a litmus paper into the solution would give an indication.
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When fossil fuels are burned, they release pollutants into the air. When hydrogen is burned, it produces clean water. There are limited amounts of fossil fuels that can be uncovered by digging in the Earth. Hydrogen must be produced from other materials, such as water, which requires using energy.
In order to determine whether replacing fossil fuels with hydrogen would be good for the environment, what question must be answered?
Answer: can hydrogen produce as much energy as burning fossil fuels?
Explanation:
Which chemical symbol describes an element? C2H6 Cl2 H2O2 CuSO4
Answer:
Cl2
Explanation:
Chlorine is a diatomic element so it is Cl 2
the others are MOLECULES (made up of atoms of ELEMENTS)
what major organic product would you expect to obtain when acetic anhydride reacts with ch3ch2ch2oh nh3
The major product of the reaction between acetic anhydride and CH3CH2CH2OH is CH3COOCH2CH2CH3. While, the major product of the reaction between acetic anhydride and NH3 is CH3CONH2.
What is acetic anhydride?Acetic anhydride is the compound (CH3COO)2. It is a precursor for the synthesis of many organic compounds.
Now let us consider the use of acetic anhydride in synthesis. The major product of the reaction between acetic anhydride and CH3CH2CH2OH is CH3COOCH2CH2CH3. While, the major product of the reaction between acetic anhydride and NH3 is CH3CONH2.
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Aerobic decomposition of organic matter requires
A.nitrogen.
B.oxygen.
C.carbon dioxide.
D.water.
Answer:
Option B: Oxygen.
Explanation:
Hope this helped.
Where does runoff end up?
a)ponds
b)streams
c)rivers
d)all of the above
Answer:
All of the above :D
Explanation:
When rain falls, if it doesn't get absorbed by the dirt, it will go into streams, rivers, and ponds. That is actually how flooding is caused!!! :D
Have an amazing day!!
Please rate and mark brainliest!!
6.11C In 1976, the Viking I Lander was sent to Mars to analyze atmospheric gases and soil samples. The Viking I Lander was most likely a
a space probe.
b lunar module.
c space shuttle.
d natural satellite.
100 points! Please help if you are able to.
Here are the balanced equations
C_2H_5OH+3O_2--->2CO_2+3H_2O+Energy2AgCl-->2Ag+Cl_2AgNO_3+Zn--->Ag+ZnNO_33BaCl_2+Al_2(SO_4)_3--->3BaSO_4+2AlCl_3H_2+I_2--->2HIDone!
What type of microorganism turns milk into yogurt?
For yogurt production, probiotic bacteria and the Streptococcus thermophilus strain work together to produce a stable balance of bacteria in the culture.
activity acid bases solutions project need help !!!!
1. Acids have highest concentration of hydronium ions.
2. Bases have highest concentration of Hydroxide ions
3. a. less than 7 b. more than 7
4. Acids (Presence of hydronium ions)
You need Conclusions too?
5. When you breathe, your lungs absorb oxygen
and release carbon dioxide. Which of these are
your lungs releasing?
(1) O
(2) O2
(3) CO
(4) CO2
(5) NH3
Write a net ionic equation for the reaction that occurs when excess hydroiodic acid and chromium(II) carbonate (s) are combined.
Step 1: Write the balanced "molecular equation:
[tex]2HI(aq) + CrCO₃ (s) → CrI₂ (s) + H₂O(l) + CO₂(g)[/tex]
Step 2: Carbon dioxide and water are written in molecular form. Consult the solubility and net ionic equation rules on the information page to determine which of the other substances will dissociate:
[tex]2HI(aq) + CrCo₃ (s) → Crl₂ (s) +H₂O(l)+CO₂(g)[/tex]
yes no yes
Step 3: Dissociate all soluble salts, strong acids, and strong bases (except calcium hydroxide), Leave together all "not soluble" salts and weak acids or bases:
[tex] {2H₂O}^{ + } (aq) + {2I}^{ - } (aq) + CrCO₃ (s)→ {Cr}^{2 + } (aq) + {2I}^{ - }(aq) + 3H₂O(l) + CO₂(g)[/tex]
Step 4: Cross out "spectator lons that appear on both sides of the reaction (these lons do not participate in the chemistry) and rewrite the "net" reaction using the smallest possible coefficients:
[tex] {2H₂O}^{ + } (aq) + CrCO₃ (s) →3H₂O + CO₂ + {Cr}^{2 + } [/tex]
What is the molarity of 4 g of NaCl in 3,800 mL of solution?
Answer:
.018 M
Explanation:
Mole weight of NaCl (from periodic chart) = 58.44 g /mole
4 g / 58.44 gm/mole = .06845 mole
.06845 mole / (3.8 liter ) = .018 M
What is the solubility of MgCO₃ in a solution that contains 0.080 M Mg²⁺ ions? (Ksp of MgCO₃ is 3.5 × 10⁻⁸)
Answer: 4.4 x 10^-7
Explanation:
The dissociation equation for this reaction is:
MgCO3 (s) → Mg+2 (aq) + CO3-2 (aq)
[tex]\text { So, } k_{s p}=(x+0.08) x[/tex] (Here 0.08 >>> x )
[tex]\begin{aligned}\Rightarrow 3.5 \times 10^{-8} &=0.08 \times x \\\Rightarrow x &=\frac{3.5}{0.08} \times 10^{-8} \\&=4.37 \times 10^{-7} \\\Rightarrow x & \approx 4.4 \times 10^{-7} \mathrm{~M}\end{aligned}[/tex]
So the solubility MgCO₃ in a solution that containing 0.080 M Mg²⁺ is 4.4 x 10^-7
How many molecules are there in a 42.3g sample of water
Answer:
This means that one mole of water molecules has a mass of 18.015g.
42.3g * 1 mole H2O/18.015g
= 2.3480 moles H2O
We are using the avogadros number to find the number of molecules of water
2.3480 H2O * 6.022*10^ 23moles/ 1mole of H2O
That's 2.3480 multiplied by 6.022*10^23 divided by 1 mole of H2O
Number of molecules = 1.4140 *10^24 molecules
what happens when muscle cells are triggered?
Answer:
When myocytes (aka muscle cells) are triggered at a certain point for awhile it can cause strain and pain throughout the muscle.
Matter is made of atoms that have positive centers of neutrons and protons
surrounded by a cloud of negatively charged electrons.
This statement is...
Answer:
the statement is a theory
Explanation:
When 3.00 g of hydrogen reacts with 4.00 g of oxygen, 4.00 g of water is formed.
(a) What is the limiting reactant?
(b) What is the theoretical yield?
(c) What is the percent yield?
Question 11 options:
a)
(a) oxygen
(b) 4.51 g
(c) 88.7 %
b)
(a) hydrogen
(b) 4.51 g
(c) 88.7 %
c)
(a) oxygen
(b) 4.05 g
(c)13.0 %
d)
(a) hydrogen
(b) 4.05 g
(c) 13.0 %
Answer:
Answer A
Explanation:
2 H2 + O2 = 2 H2O
knowing the mole weights of these elements shows O2 is the limiting reactant in this situation.
4 g oxygen is 4 /31.998 = .125 mole O2
We should get two times these moles of water = .250 moles
weight = .250 (1.008 * 2 + 15.999) = 4.50 gm H20 (theoretical)
....but we only got 4 gm
4/4.50 = 88.8%
If 25.0 mL of a 2.00 M HCl solution is diluted to 2.00 L, what is the molarity of the new solution?
The molarity of a new solution that has a volume of 25.0 mL of a 2.00 M HCl solution and diluted to 2.00 L is 0.025M.
How to calculate molarity of a solution?The molarity of a solution can be calculated using the following formula:
C1V1 = C2V2
Where;
C1 = initial concentrationC2 = final concentrationV1 = initial volumeV2 = final volume2 × 25 = 2000 × C2
50 = 2000C2
C2 = 50 ÷ 2000
C2 = 0.025M
Therefore, the molarity of a new solution that has a volume of 25.0 mL of a 2.00 M HCl solution and diluted to 2.00 L is 0.025M.
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Which of the following is an example of chemical weathering?
A. A river carrying dirt into a lake.
B. Wind carrying sand from a beach.
C. Chemicals in water dissolving minerals in rock.
D. Friction between two rock surfaces grinding away minerals.
Answer:
C
Explanation:
Answer: D. Friction between two rock surfaces grinding away minerals.
Explanation: chemical weathering involves erosion from rocks/materials
What is the molarity of a solution that has 175 g of LICI in 1085 mL of solution?
Answer:
3.8 M
Explanation:
Mole weight of LiCl = 6.94 + 35.45 = 42.39 ( from periodic table)
175 g of this is then 175 / 42.39 = 4.13 moles
4.13 moles / (1085/1000) = 3.8 M
A 25.0-L balloon at 20.0 ⁰C is placed in a hot water bath at 90 ⁰C. After 15 minutes, the volume of the balloon stops expanding. What is the new volume of the balloon?
Apply Charles law
V1T2=V2T125(90)=20V225(9)=2V2225=2V2V2=225/2V2=112.5L