Answer: Special care is required to prepare a solution of sodium hydroxide or NaOH in water because considerable heat is liberated by the exothermic reaction. The solution may splatter or boil. Here is how to make a sodium hydroxide solution safely, along with recipes for several common concentrations of NaOH solution.
Explanation:
Hope this helps!
does xef4 have resonance structure?
Answer:
Yes
Explanation:The structure of XeF4 is square planar.
Is water wet? Why or why not
Answer: umm, yes? DUH
Explanation: touch some falling out of a tap
Answer:
Water is wet,
Explanation:
in the sense of being a liquid which flows easily, because its viscosity is low, which is because its molecules are rather loosely joined together. So it is wet.
When 3.93 grams of lactic acid, CHoOs(s), are burned in a bomb
calorimeter that has a total heat capacity of 10.80 kJ-K-1, the
temperature of the calorimeter increases by 5.43 K. Assume AHrxn
=
AErxn. Given that AH°f of H¿O(I) = -285.8 kJ-mol-1 and AH°f of CO:(g)
= -393.5 kJ• mol-1, calculate the AH°f of lactic acid.
The heat released in the combustion of lactic acid is absorbed by the
calorimeter and in the decomposition of the lactic acid.
ΔH°f of lactic acid is approximately -716.2 kJ
Reasons:
Known parameters are;
Mass of the lactic acid = 3.93 grams
Heat capacity of the bomb calorimeter = 10.80 kJ·K⁻¹
Change in temperature of the calorimeter, ΔT = 5.34 K
ΔHrxn = ΔErxn
ΔH°f of H₂O(l) = -285.8 kJ·mol⁻¹
ΔH°f of CO₂(g) = -393.5 kJ·mol⁻¹
The chemical equation for the reaction is presented as follows;
C₃H₆O₃ + 2O₂ → 3CO₂ + 3H₂OThe heat of the reaction = 10.80 kJ·K⁻¹ × 5.34 K = 57.672 kJ
Molar mass of C₃H₆O₃ = 90.07 g/mol
Number of moles of C₃H₆O₃ = [tex]\dfrac{3.93 \, g}{90.07 \, g/mol}[/tex] = 0.043633 moles
Number of moles of CO₂ produced = 3 × 0.043633 moles = 0.130899 moles
Heat produced = 0.130899 mole × -285.8 kJ·mol⁻¹ = -37.4109342 kJ
Moles of H₂O produced = 0.130899 moles
Heat produced = 0.130899 mole × -393.5 ≈ -51.51 kJ
Therefore, we have;
Heat absorbed by the lactic acid = ΔH°f of H₂O + ΔH°f of CO₂ + Heat absorbed by the calorimeter
Which gives;
Heat absorbed by lactic acid = -37.4109342 kJ - 51.51 kJ + 57.672 kJ ≈ -31.249 kJ
The heat absorbed by the lactic acid ≈ -31.249 kJ
[tex]\Delta H^{\circ}f \ of \ C_3H_6O_3 = \dfrac{-31.249}{0.043633} \approx -716.2[/tex]
ΔH°f of C₃H₆O₃ ≈ -716.2 kJ
Heat of formation of lactic acid ≈ -716.2 kJ.
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The temperature at which a solid melts is the same as the temperature at which its liquid form solidifies (true or false)
its false not true................
Answer:
True
Explanation:
This is true because, upon cooling the particles in a liquid loses energy, stops moving and remains constant and the forms a solid.
Therefore we can say the freezing point and melting point occurs at the same temperature
It is important to understand that while the absorbance value is related to the amount of light absorbed by a sample, it is not equal to or directly proportional to the amount of light absorbed. Consider a situation where 100 photons of light pass through a sample. After the light passes through the sample, 64 photons are detected. a) How many photons were transmitted through the sample
When 100 photons of light pass through a sample and 64 photons are detected after the passage of light, the number of photons transmitted through the sample is 64.
This is based on the methods of calculating the absorbance of light, which is depicted as the higher the amount of light transmission, the lower the amount of light absorbed.
Thus, when 64 photons of light in 100 photons are detected, 64 photons are transmitted, and therefore, the number of photons absorbed is 36.
Hence, hypothetically, if 100 photons of light are transmitted, 0 photons of light will be absorbed.
Therefore, in this case, it is concluded that the correct answer is 64 photos.
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4. Some biologists declare "structure determines functions." The 3-D molecular geometry in small molecules (or units of molecules) are critical in the final shape of larger structures. Give an example, not found in your notes or textbook that illustrate how a change a final shape can affect how the structure functions (or how other substances interact with it) and explain your choice.
what mass of water (in grams) is produced by the reaction of 23.0 g of SiO2?
The mass of water produced by the reaction of the 23 g of [tex]SiO_2[/tex] is 13.8 g.
The given chemical reaction;
[tex]4Hf (g) \ + \ SiO_2 (s) \ --> \ SiF_4(g) \ + \ 2H_2O(l)[/tex]
In the given compound above, we can deduce the following;
molecular mass of [tex]SiO_2[/tex] = 28 + (2 x 16) = 60 gmolecular mass of [tex]2H_2O[/tex] = 2(18) = 36 g60 g of [tex]SiO_2[/tex] --------- 36 g of water
23 g of [tex]SiO_2[/tex] ------------- ? of water
[tex]mass \ of \ water = \frac{23 \times 36}{60} = 13.8 \ g \ of \ water[/tex]
Thus, the mass of water produced by the reaction of the 23 g of [tex]SiO_2[/tex] is 13.8 g.
"Your question is not complete, it seems to be missing the following information";In the reaction of the given compound, [tex]4Hf (g) \ + \ SiO_2 (s) \ --> \ SiF_4(g) \ + \ 2H_2O(l)[/tex], what mass of water (in grams) is produced by the reaction of 23.0 g of SiO2?
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What is volume?
A. The amount of space an object takes up
B. The amount of matter in an object or substance
C. The length of an object
D. The number of particles in an object or substance
Answer:
Volume is the amount of space an object takes up. I hope this helps you! :D
explain the role of sulphuric acid in limit test for iron
A chemical reaction takes place in a closed system. The mass of the reactants before the reaction was grams. What must the mass of the products of the reaction be, according to the law of conservation of mass?
A. 35 grams B. 30 grams C. 70 grams D. 25 grams
Answer:
D. 25 grams
Explanation:
I think that's what the answer is
Determine the total mass of 5 moles of CuSO4.5H2O
Answer:
Answer: 1247.5 grams
Explanation:
explanation on image .
Calculate the pOH of an aqueous solution of .0.073 M LiOH
Considering the definition of pOH and strong base, the pOH of the aqueous solution is 1.14
The pOH (or potential OH) is a measure of the basicity or alkalinity of a solution and indicates the concentration of ion hydroxide (OH-).
pOH is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:
pOH= - log [OH⁻]
On the other hand, a strong base is that base that in an aqueous solution completely dissociates between the cation and OH-.
LiOH is a strong base, so the concentration of the hydroxide will be equal to the concentration of OH-. This is:
[LiOH]= [OH-]= 0.073 M
Replacing in the definition of pOH:
pOH= -log (0.073 M)
pOH= 1.14
In summary, the pOH of the aqueous solution is 1.14
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brainly.com/question/16032912?referrer=searchResults brainly.com/question/13557815?referrer=searchResultsWhich two phrases describe the movement of thermal energy due to
convection currents in the water on Earth?
O A. From the bottom of the ocean to the surface
B. From the surface of the ocean to the bottom
C. From cooler parts of Earth to the equator
D. From the equator to cooler parts of Earth
Answer:
D. From the equator to cooler parts of Earth
Explanation:
Thermal energy is always transferred from an area with a higher temperature to an area with a lower temperature. Moving particles transfer thermal energy through a fluid by forming convection currents.
Answer:
B. From the surface of the ocean to the bottom
D. From the equator to cooler parts of Earth
Explanation:
Test approved
Vitamin D is produced in the skin when 7-dehydrocholesterol reacts with UVB rays (ultraviolet B) having wavelengths between
270 nm and 300 nm. What is the energy range Emin < E< Emax of the UVB photons?
The energy range expected is 6.6 × 10^-19 J < E < 7.33 × 10^-19 J
The energy of the photon is given by;
E = hc/λ
E = energy of the photon
h = Plank's constant
c = speed of light
λ = wavelength of light
For the upper boundary range;
E = ?
h = 6.6 × 10^-34 Js
c = 3 × 10^8 m/s
λ = 270 × 10^-9
E = 6.6 × 10^-34 Js × 3 × 10^8 m/s / 270 × 10^-9
E = 7.33 × 10^-19 J
For the lower range;
E = ?
h = 6.6 × 10^-34 Js
c = 3 × 10^8 m/s
λ =300 × 10^-9
E = 6.6 × 10^-34 Js × 3 × 10^8 m/s / 300 × 10^-9
E = 6.6 × 10^-19 J
Hence, the energy range 6.6 × 10^-19 J < E < 7.33 × 10^-19 J
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What elements are in H2F5BLi and how many atoms are in each element.
20 point plus brainliest
Answer:
2 hydrogen
5 fluorine
1 boron
1 lithium
Is this equation balanced and in the lowest form?
4NH3 → 2N2 + 6H2
Answer:
It's balanced but not in the lowest form
Explanation:
The actual equation is given by
[tex]\\ \sf\longmapsto 2NH_3\longrightarrow N_2+3H_2[/tex]
Is halogen radioactive
Answer: yes
Explanation:
Increasing the frequency _________________ the wavelength. Group of answer choices decreases increases does not change
Answer:
heightens
Explanation:
The flask contains 25 mL of an unknown diprotic acid aqueous solution that reacts in a 1:2 stochiometric ratio with NaOH. Titrate the solution with NaOH to determine the concentration of the acid. Perform a titration by setting the concentration of the NaOH solution and adding it to the acid solution using the different Add Base buttons. The equilvalence point of the titration is passed when the indicator color changes. The unknown sample can be titrated multiple times by pressing the Retitrate button and starting over. Enter the concentration of the unknown acid solution.
To obtain accurate results, follow the following procedure:
switch the indicator to phenolphthalein titrate 1 mL at a time until solution turns pink, make note of volume added retitrate add 1 mL at a time until 1 mL less than the first titration add 0.05 mL at a time until the solution just turns pink
Answer:
The flask contains 25 mL of an unknown diprotic acid aqueous solution that reacts in a 1:2 stochiometric ratio with NaOH. Titrate the solution with NaOH to determine the concentration of the acid. Perform a titration by setting the concentration of the NaOH solution and adding it to the acid solution using the different Add Base buttons. The equilvalence point of the titration is passed when the indicator color changes. The unknown sample can be titrated multiple times by pressing the Retitrate button and starting over. Enter the concentration of the unknown acid solution.
Explanation:
What is the main component of natural gas
Answer:
I believe that would be methane! I hope this helps you!
Answer:
methane
Explanation:
The largest component of natural gas is methane, a compound with one carbon atom and four hydrogen atoms (CH4). Natural gas also contains smaller amounts of natural gas liquids (NGL, which are also hydrocarbon gas liquids), and nonhydrocarbon gases, such as carbon dioxide and water vapor.The main component in natural gas is methane. It also has ethane, propane, butane, hydrocarbons.
A 5.60 g sample of a weak acid with
Ка 1.3 x 10-4 was combined with 5.00 mL of
5.80 mol L-1 NaOH and the resulting solution
was diluted to 750 mL. The measured pH of the
solution was 4.35.
What is the molar mass of the weak acid
Answer:
pKa = - log Ka = - log (1.3 * 10^-4) = 3.886 5.20 mL of 6.20 M NaOH = 0.00520 L * 6.20 mole…
Explanation:
where does fertilization occurs in human beings
In human beings fertilization occurs in fallopian tube
Answer:
Fertilization usually takes place in a fallopian tube that links an ovary to the uterus. If the fertilized egg successfully travels down the fallopian tube and implants in the uterus, an embryo starts growing.
Rank the given objects from having the biggest size to the smallest size Blood cells , virus, atom, electrons , paper
Answer:
paper, blood cell, virus, electron, atom
Explanation:
Compost from vegetable peelings can be used as plant fertilizer. * a. reduce b. resuse c. recycle d. recover
Answer:
Is letter B
Explanation:
Hope it helps :))
similarities between viruses and fungi
Answer:
I can't think of any similarities at all.
Viruses are just an aggregation of genomic material and protein. Occasionally lipid folds around it to make a covering called an envelope.
Fungi are living, eukaryotic cells that metabolize, grow, perform energy conversions and mate with each other.
Covert 645g of CuCl2 to mole
Answer:
kombinasi kuda-kuda belakang
Explanation:
maaf kalau salahnya
28.5 g of iron shot is added to a graduated cylinder containing 45.50 mL of water. The water level rises to the 49.10 mL mark. From this information, calculate the density of iron.
HELLPPP CAN SOMEONE SOLVE THIS???
Answer:
Density if iron shot = 7.92 g/ml (2 sig. figs.)
Explanation:
By definition, density is mass per unit volume. That is,
Density (D) = mass(m)/Volume(V)
mass(m) = 28.5g (given)
Volume(V, of iron shot) = 49.10ml - 45.5ml = 3.6ml
Substitutuing into D = m/V = 28.5g/3.6ml = 7.9166667 g/ml (calc.ans)
≅ 7.92 g/ml (2 sig. figs.)
Hope this helps. :-)
does ch3 have resonance structure?
Answer:
yes
Explanation:
if u watch or look closely u will observe it
The CH₃ has resonance structures as it has odd number of hydrogen atoms.
In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures ,also variously known as resonance structures or canonical structures into a resonance hybrid (or hybrid structure) in valence bond theory. It has particular value for analyzing delocalized electrons where the bonding cannot be expressed by one single Lewis structure.
Thus, CH₃ has resonance structures as it has odd number of hydrogen atoms.
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What will happen to the pH of sodium bicarbonate if vinegar is added to it?
Answer:
The overall chemical reaction between baking soda (sodium bicarbonate) and vinegar (weak acetic acid) is one mole of solid sodium bicarbonate reacts with one mole of liquid acetic acid to produce one mole each of carbon dioxide gas, liquid water, sodium ions, and acetate ions. The reaction proceeds in two steps
I may need some help with this one
Answer:
ssihh add then htit da
Explanation: