Answer:
Aspirin was purified in the lab by recrystallizing the crude aspirin. The melting point of the purified aspirin is expected to be lower than the melting point of crude aspirin.
Explanation:
The presence of impurities in a sample lowers the melting point of the impure substance. Hence the melting point of an impure substance is always less than the melting point of the corresponding pure substance.
Bearing this in mind, the statement "Aspirin was purified in the lab by recrystallizing the crude aspirin. The melting point of the purified aspirin is expected to be lower than the melting point of crude aspirin." is found to be false since impure substances tend to have a slightly lower melting point than the pure substance, and a broader melting temperature range.
When aqueous solutions of potassium nitrite and nitric acid are mixed, an aqueous solution of potassium nitrate and nitrous acid results. Write the net ionic equation for the reaction.
Nitric acid and potassium nitrite reacted together potassium nitrate and nitrous acid forms. The net ionic equation for the reaction is given below:
[tex]\rm K^{+} (aq)+ NO_{3} ^{-} (aq)\rightarrow KNO_{3}(s)[/tex]
What is ionic equation?A balanced reaction represents all the reactants and products in perfect stoichiometry. Thus, each element have to be equal in number on both side.
A balanced ionic equation represents all the ions participating in a reaction and with their charges balanced on both side and state of the reaction is given in brackets. Net ionic equation represents the formation of a solid precipitate.
The complete ionic equation of reaction of one mole of potassium nitrite with one mole of nitric acid is given below:
[tex]\rm K^{+} + NO_{2}^{-}(aq) + H^{+} (aq) +NO_{3}^{-}(aq) \rightarrow H^{+} (aq) + NO_{2}^{-}(aq) + KNO_{3} (s)[/tex]
Cancelling the aqueous ions from both sides we get the net ionic equation representing the formation of solid potassium nitrate as shown here:
[tex]\rm K^{+} (aq)+ NO_{3} ^{-} (aq)\rightarrow KNO_{3}(s)[/tex]
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How many grams of ammonium fluoride, , must be dissolved to prepare 300. mL of a 0.234 M aqueous solution of the salt
Answer:
24.24 g
Explanation:
First we calculate how many moles are there in 300 mL of a 0.234 M solution, using the definition of molarity:
Molarity = moles / litersConverting 300 mL to L ⇒ 300 mL / 1000 = 0.300 L
0.234 M = moles / 0.300 Lmoles = 0.78 molesThen we convert 0.78 moles of NH₄F into grams, using its molar mass:
0.78 mol * 31.073 g/mol = 24.24 gWhat is the pH if the [H+] concentration is 3 x10^-13
Answer:
pH = 12.52
Explanation:
Given that,
The [H+] concentration is [tex]3\times 10^{-13}[/tex].
We need to find its pH.
We know that, the definition of pH is as follows :
[tex]pH=-log[H^+][/tex]
Put all the values,
[tex]pH=-log[3\times 10^{-13}]\\\\pH=12.52[/tex]
So, the pH is 12.52.
What transition energy corresponds to an absorption line at 460 nm?
A. 6.52 x 10-19 J
B. 4.32 x 10-19 J
C. 4.45 x 10-19 J
D. 2.31 x 10-19 J
Answer:
B. 4.32 x 10-19 J is correct via a p e x
Explanation:
In Atom, what is a heavier sub-atomic particle than the others and explain why
The nucleons are havier in sub atomic particle like neutrons and protons.
fun fact i read in a book even 1cm³ of nucleons are around 2 million Kg which you can't pick up by hand even by machines like buldozer.
which is best illustrated by Watson and Crick's ball and stick model of dna
Answer:
Here is your Answer.......
Explanation:
The Watson and Crick's ball-and-stick model of DNA best illustrates the role of creativity in scientific discovery
Alcohols have more hydrogen bonding .
(True or False) ?!
Answer:
True
Explanation:
An alcohol is an organic molecule containing an -O-H group. Any molecule which has a hydrogen atom attached directly to an oxygen or a nitrogen is capable of hydrogen bonding.
a. acidic
b. basic
; neutral
d. will not be affected
Find the molarity of 10% NaOH.[MOE 2003
a. 1.5
b! 2.5
c. 4
d. 0.4
10 ml of 2.5 N NaOH is mixed with 20 ml of
N HCI. The mixture is diluted to 100 ml. WI
is the nature of mixture?
IMOF 20
1. You didn't post the question to Number 1.
2.
10% means There's 10g in 100ml of this solution.
This is the weight/volume(w/v) expression of concentration.
So
We have Mass =10g
volume =100ml
Molarity = Moles of solute/volume of solution(in LITRES)
Moles=Mass/Molar mass
Molar mass of NaOH=40g/mol
Mole=10/40
=0.25mole
Volume =100ml =0.1Litres
MOLARITY=0.25/0.1 =
=2.5M
OPTION B.
3. NOTE: THE MOLARITY AND NORMALITY OF NAOH AND HCL ARE THE SAME(This doesn't happen for all compounds tho)
So We can take 2.5N(Normality) of NaOH to be 2.5M(Molarity) NaOH
I think you forgot to write the Normality of the second one. I'll take it to be 1N. Maybe you can then Input supposed value when you're solving on your own
So
1N HCl is same as 1M HCL
We were given their respective volumes
2.5M NaOH can also be written as 2.5mole/volume(in Liters)
The volume of NaOH =10ml or 0.01L
Moles = 2.5mole/L x 0.01L
You notice that Liters on top and bottom cancels out... leaving the moles
So
Mole=0.01x2.5 = 0.025moles of NaOH
we're gonna do the same for 1N HCl in 20ml(0.02L)
So
Mole = 1 x 0.02 =0.02moles
Total Mole = 0.02 + 0.025 =0.045moles
The Final Volume is 100ml as stated in the question. It was diluted to 100ml or 0.1L
So
Final Concentration In Molarity
= Total Moles/Volume in L
=0.045/0.1
=0.45M.
Question 1
Where does photosynthesis happen in a plant cell?
O Cell membrane
O Cell wall
O Chloroplast
O Mitochondria
Answer:
Chloroplast
Explanation:
Photosynthesis happens in chloroplast of plants. Mitochondira is where the cellular respiration happens.
how do the hydrosphere and atmosphere interact? give an example
Answer:
Evaporation
Explanation:
Water in the ocean, rivers, lakes, etc. is part of the hydrosphere, and when that water evaporates it enters the atmosphere
Observe: Click Reset (). The electrons in the outermost orbit, called valence electrons, help to create chemical bonds. Create a lithium atom (3 protons, 4 neutrons, 3 electrons). How many valence electrons are in a neutral lithium atom?
Answer:
There is one valence electron in a neutral lithium atom.
Explanation:
The number of valence electrons in a neutral lithium atom is equal to one.
What is a valence electron?Valence electrons can be described as the electrons filling the outermost shell of an atom while the electrons in the inner shell of an atom are known as core electrons. Lewis structures are used to determine the number of valence electrons and know the types of chemical bonds.
Valence electrons of an atom can be filled in the same or different orbitals and these electrons are responsible for the interaction between atoms and cause the formation of chemical bonds.
Only electrons occupied in the outermost shell can participate in the formation of a bond or a molecule and are responsible for the reactivity of the element.
The number of electrons in the neutral atom of lithium is 3. There is only one electron present on the outermost shell 2s-orbital.
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What do all fossil fuels have in common?
O A. They are all liquids.
OB. They all contain crude oil.
O C. They all produce nitrogen as a combustion product.
O D. They are all nonrenewable energy sources.
Answer:
Your answer would be D, they are all non-renewable energy sources. Hope this helps!
Answer:
D. They are all nonrenewable energy sources.
a gas tank contains 15 moles of oxygen and 20 moles helium what is apertial pressure of helium in this mixture
Answer:
D0wnload Phot0Math......................
Explanation:
Brainiest and 10 Points
Which has a HIGHER frequency?
A. Visible
B. Ultraviolet
Answer:
B. Ultraviolet
Explanation:
UV has a higher frequency and shorter wavelength than visible light
Explain why this combination of compounds can or cannot make a buffer solution. Hint: apply definition of a buffer, mechanism of its action and consider whether the compound is acid (weak/strong) or base (weak/strong). HF (0.2 mol) and NaOH (0.1 mol)
Answer:
This combination can make a buffer
Explanation:
A buffer is defined as an aqueous mixture of a weak acid and its conjugate base, or vice versa.
In the problem, HF is a weak acid, and its conjugate base is F⁻.
When NaOH reacts with HF, F⁻, Na⁺ and H₂O are produced as follows:
NaOH + HF → F⁻ + Na⁺ + H₂O
As there are initially 0.2mol of HF and 0.1mol NaOH, after the reaction you will have:
0.1mol HF and 0.1mol F⁻. As both, the weak acic and the conjugate base are present:
This combination can make a buffer
How many atoms in total are there in 7.35 mol of magnesium oxide (MgO)
molecules?
Answer:
4.42 x 10^24
Explanation:
The area of a telescope lens is 6507 x 10^3 mm^2. What is the area in square feet, enter your answer in scientific notation. If it takes a technician 51.6 s to polish 1.68 x 10^2 mm^2 how long does it take her to polish the entire lens ?
Answer: the area of the telescope lens is \textit{0,08507 ft}
Explanation: Happy I could help!
Identify the true statement(s). There may be one answer or more than one answer.FADH2 is a reducing agent. FADH2 is an oxidizing agent. NADH is an oxidizing agent. NADPH is a reducing agent. FAD is an oxidizing agent.
Answer:
FADH2 is a reducing agent.
FAD is an oxidizing agent.
Explanation:
The full form of FAD is flavin adenine dinucleotide. It is mainly a redox-active coenzyme which is associated with the different proteins and is involved with the enzymatic reactions in the metabolism.
FAD is obtained by donating or accepting electrons.
In the citric acid cycle,
succinate + FAD → fumarate + [tex]$FADH_2$[/tex]
Thus we see that FAD is an oxidizing agent while [tex]$FADH_2$[/tex] is a reducing agent.
When an acetic acid solution is titrated with sodium hydroxide, the slope of the titration curve (pH versus volume of NaOH added) increases when sodium hydroxide is first added. This change shows that ________
Answer:
When an acetic acid solution is titrated with sodium hydroxide, the slope of the titration curve (pH versus volume of NaOH added) increases when sodium hydroxide is first added. This change shows that acetic acid is being converted to sodium acetate.
Explanation:
ABOUT TITRATION - Titration is a chemical analysis method for determining the amount of a constituent in a sample by adding an exact known quantity of another substance to the measured sample with which the desired constituent reacts in a specific, known proportion. A burette, which is essentially a long, graduated measuring tube with a stopcock and a delivery tube at the bottom end, is used to gradually administer a standard solution of titrating reagent, or titrant.
It is feasible to identify a good visual color indicator for many titration processes that will signify the end point at, or very near to, the equivalence point.
Acid-base titrations, precipitation titrations, complex-formation titrations, and oxidation-reduction (redox) titrations are examples of such titrations, which are categorised according to the nature of the chemical reaction that occurs between the sample and the titrant.
Titrations of metal ions with the reagent disodium ethylenediaminetetraacetate are the most important titrations based on complex-formation processes (a salt of edetic acid, or EDTA).
Hence , the answer is that acetic acid is converted into sodium acetate.
Pure magnesium metal is often found as ribbons and can easily burn in the presence of oxygen. When 3.31 g of magnesium ribbon burns with 8.45 g of oxygen, a bright, white light and a white, powdery product are formed. Enter the balanced chemical equation for this reaction. Be sure to include all physical states.
Answer:
2Mg(s) + O2(g) ----->2MgO(s)
Explanation:
In writing a balanced chemical reaction equation, the rule of thumb is that the number of atoms of each element on the reactant side must be the same as the number of atoms of the same elements on the products side.
Hence for the reaction of magnesium and oxygen shown below;
2Mg(s) + O2(g) ----->2MgO(s)
We notice that there are two atoms each of magnesium and oxygen on both sides of the reaction equation hence the equation is balanced.
If the atomic number of an element is 14, the identity of the element must be
A. Nitrogen
B. Silicon
C. Carbon
D. Niobium
Answer:
silicon
Explanation:
because silicon has 14 electrons and protons
As the diagram model the processo se reproduction lomon) formand change formation Sexual reproduction results in a child that is different from its parents because
A. the child receives all of is genetic information from its mother
B. the child produces its own genetic information once it is formed
C. the child receives half of is genetic information from each parent
D. the child receives all of it's genetic information from it's father there
Answer:
The answer is C. the child receives half of is genetic information from each parent
Explanation:
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You start with 0.1 L of a 5.00 M solution, and you plan to dilute it to make a
solution with a concentration of 0.625 M. How much water did you add to
the container?
a) 800ML
b) 100ml
c)700ml
d)750ml
Which type of molecule is shown below?
A. Cyclic alkene
B. Alkene
C. Alkyne
D. Cyclic alkane
Answer:
D. Cyclic alkane
Explanation: there is no double or triple bond
The type of molecule that is shown below in the picture is a cyclic alkane. The correct option is D.
What is the cyclic alkane?This is the compound that contain hydrogen and carbon bond. They are mono cyclic saturated hydrocarbons.
These are the atoms that replace the hydrogen atom in an organic compound.
Thus, the correct option is D. Cyclic alkane.
Learn more about cyclic alkane
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I need help Type th temperature (in Kelvin) in the left column and the volumes in the right column, being sure to keep pairs of data together. then click resize window to fit data.
the data appears to be
linear
quadratic
exponential
logarithmic
Answer:
Linear
Explanation:
HELP! ASAP! Iron (Fe) and copper (II) chloride (CuCl2) combine to form iron (III) chloride (FeCl3) and copper (Cu). If you start with 155,8 grams of
iron (Fe), how many grams of copper (Cu) will be produced?
2Fe + 3CuCl2 à 2FeCl3 + 3Cu
Answer: 30.978
Explanation:
From the equation 2 moles of Fe will result in 3 moles copper
so .325 moles Fe will result in .4875 moles Cu
Cu weights 63.546 gm per mole
.4875 moles * 63.546 gm / mole = 30.978 gm of Cu
1. What is the oxidation state of iron in FeC2O4
Answer:
+2
Explanation:
I am first with correct answer
Answer:
the oxidation state of iron in FeC2O4 is +2
A gas at STP occupies 0.055 L of space. If the pressure changes to
2.8 atm and the temperature increases to 195°C, what is the new
volume?
Answer:
0.034 L
Explanation:
From the question given above, the following data were obtained:
Initial volume (V₁) = 0.055 L
Initial pressure (P₁) = stp = 1 atm
Initial temperature (T₁) = stp = 273 K
Final pressure (P₂) = 2.8 atm
Final temperature (T₂) = 195 °C = 195 °C + 273 = 468 K
Final volume (V₂) =?
The final volume of the gas can be obtained as follow:
P₁V₁ / T₁ = P₂V₂ / T₂
1 × 0.055 / 273 = 2.8 × V₂ / 468
0.055 / 273 = 2.8 × V₂ / 468
Cross multiply
273 × 2.8 × V₂ = 0.055 × 468
764.4 × V₂ = 25.74
Divide both side by 764.4
V₂ = 25.74 / 764.4
V₂ = 0.034 L
Therefore, the new volume of the gas is 0.034 L.
Calculate the volume occupied
at s.t.p by 6.89
gas [H = 10, N = 14
Answer:
9.07 L
Explanation:
Calculate the volume occupied at s.t.p by 6.89 g of NH₃ gas [H = 1.0, N = 14.0].
Step 1: Given and required data
Mass of NH₃ (m): 6.89 gMolar mass of NH₃ (M): 17.0 g/molStep 2: Calculate the moles (n) of NH₃
We will use the following epxression.
n = m / M
n = 6.89 g / (17.0 g/mol) = 0.405 mol
Step 3: Calculate the volume occupied by 0.405 moles of NH₃ at STP
At STP, 1 mole of NH₃ occupies 22.4 L (assuming ideal behavior).
0.405 mol × 22.4 L/1 mol = 9.07 L
what is the name of the functional group of pentanoic acid
Answer:
organic acid
Explanation:
Answer:
Hey mate.....
Explanation:
This is ur answer.....
Alkyl carboxylic acid
Valeric acid (pentanoic acid) is a straight-chain alkyl carboxylic acid with a very unpleasant odor. It is found naturally in the perennial flowering plant valerian (Valeriana officinalis), from which it gets its name.
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