It last longer because it slows down the spread of bacteria.
Temperature, concentration, particle size, use of a catalyst.
In an experiment, you added a base, NaOH, one mL at a time to 50 mL acetate buffer and recorded the pH. For the first 6 mL NaOH the pH increased from 4.5 to 4.9. At the 7th mL the pH was 6.6 and by the 8th mL the pH was 10.7. Knowing what you do about titrating acetate buffer with acid, is this experimental result what you expected or is it not expected
Answer:
yes the experimental result is the expected result .
Explanation:
When Titrating acetate buffer with acid the PH will decrease gradually from a more neutral PH to a more acidic level and this is because buffer solutions are prepared with weak acids and its conjugate base.
The results gotten from the continuous addition of base NaOH to the acetate buffer is the expected result because the base is been absorbed by the buffer solution and it is converted to a conjugate base of the buffer solution which will gradually increase the PH level of the solution as more conjugate base is formed due to the addition of more NaOH.
There are four different starting molecules that one might use to synthesize the illustrated alkyl halide as the major product using an electrophilic addition reaction. Please draw all four of them.
Answer:
Explanation:
An electrophilic addition reaction occurs when an electrophile attacks a substrate, with the end result being the inclusion of one or many comparatively straightforward molecules along with multiple bonds.
In the given question, the hydrogen bromide provides the electrophile while the bromide is the nucleophile. The mechanism proceeds with the attack of the electrophile on the carbon, followed by deprotonation. This process is continued with a formation of carbocation and the bromide(nucleophile) finally bonds to the carbocation to form a stable product.
The first diagram showcases the possible various starting molecules for the synthesis while the second diagram illustrates their mechanism.
atomic number of element is 15 write a formula of an oxide
Answer:
Atomic Number. 15=phosphorus
Valency=3
So, Oxide=P203
what would be the mass of 44.8 L of CO2 gas at STP?
show work if possible
Answer:
[tex]m=88.02g[/tex]
Explanation:
Hello there!
In this case, for this ideal gas law problem, it turns out necessary for us to remember that one mole of any gas is contained in 22.4 L at STP and therefore, we can use the following ratio to calculate the moles in 44.8 L of CO2:
[tex]\frac{1mol}{22.4L} =\frac{x}{44.8L}\\\\x= \frac{1mol*44.8L}{22.4L}=2mol[/tex]
Finally, since the molar mass of CO2 is 44.01 g/mol, we calculate the mass as follows:
[tex]m=2mol*\frac{44.01g}{1mol}\\\\m=88.02g[/tex]
Regards!
At 35°C, K = 1.6 × 10^-5 for the reaction
2 NOCl(g) ⇌ 2 NO(g) + Cl2(g)
Calculate the concentrations of all species at equilibrium for each of the following original mixtures.
a. 2.0 mol pure NOCl in a 2.0 L flask
b. 2.0 mol NOCl and 1.0 mol Cl2 in a 1.0 L flask
Answer:
a) [NOCl] = 0.968 M
[NO] = 0.032M
[Cl²] = 0.016M
b) [NOCl] = 1.992M
[NO] = 0.008 M
[Cl2] = 1.004 M
Explanation:
Step 1: Data given
Temperature = 35°C = 308K
K = 1.6 × 10^-5
Step 2: The reaction
2 NOCl(g) ⇌ 2 NO(g) + Cl2(g)
For 2 moles NOCl we'll have 2 moles NO and 1 mol Cl2
Step 3
a. 2.0 mol pure NOCl in a 2.0 L flask
Concentration at the start:
Concentration = mol / volume
[NOCl] = mol / volume
[NOCl] = 2.0 / 2.0 L
[NOCl] = 1.0 M
[NO] = 0 M
[Cl] = 0M
Concentration at the equillibrium
[NOCl] = 1.0M - 2x
[NO] = 2x
[Cl2]= x
K = [Cl2][NO]² / [NOCl]² = 1.6*10^-5
1.6*10^-5 = ((2x)² * x) / (1.0-2x)²
x = 0.016
[NOCl] = 1.0 - 2*0.016 = 0.968 M
[NO] = 2*0.016 = 0.032M
[Cl²] = 0.016M
b. 2.0 mol NOCl and 1.0 mol Cl2 in a 1.0 L flask
Concentration at the equillibrium
[NOCl] = 2.0 mol / 1.0 L = 2.0 M
[NO] = 0 M
[Cl2]= 1.0 mol / 1.0 L = 1.0 M
Concentration at the equillibrium
[NOCl] = 2.0M - 2x
[NO] = 2x
[Cl2]= 1.0 + x
K = [Cl2][NO]² / [NOCl]² = 1.6*10^-5
1.6 *10^-5 = (2x)²*(1.0+x) / ((2.0-2x)²)
1.6 *10^-5= (2x)² * 1 )/2.0²
1.6 *10^-5= 4x² / 4 = x²
x = [tex]\sqrt{1.6 *10^-5}[/tex] = 4.0*10^-3
[NOCl] = 2.0 - 2*0.004 = 1.992M
[NO] = 2*0.004 = 0.008 M
[Cl2] = 1+ 0.004M = 1.004 M
g The boiling of water is a Question 4 options: chemical and physical damage chemical change because a gas (steam) is given off chemical change because heat is needed for the process to occur physical change because the water merely disappears physical change because the gaseous water is chemically the same as the liquid
Answer:
physical change because the gaseous water is chemically the same as the liquid
Explanation:
Matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states.
Generally, matter exists in three (3) distinct or classical phases and these are; solid, liquid and gas.
A physical change can be defined as a type of change that only affects the physical form of a chemical substance (matter) without having any effect on its chemical properties. Thus, a physical change would only affect the physical appearance and properties of a chemical substance (matter) but not its chemical properties.
This ultimately implies that, a physical change result in a change of matter from one form or phase (liquid, solid or gas) to another without a corresponding change in chemical composition.
Hence, the boiling of water is considered to be a physical change because the gaseous water is chemically the same as the liquid i.e there isn't any changes in chemical composition of water when boiling.
Compare the solubility of calcium sulfite in each of the following aqueous solutions:
a. 0.10 M Ca(CH3COO)2
b. 0.10 M K2SO3
c. 0.10 M NaNO3
d. 0.10 M KCH3COO
1. More soluble than in pure water.
2. Similar solubility as in pure water.
3. Less soluble than in pure water.
Answer:
0.10 M Ca(CH3COO)2- Less soluble than in pure water.
0.10 M K2SO3- Less soluble than in pure water.
0.10 M NaNO3 - More soluble than in pure water.
0.10 M KCH3COO- Similar solubility as in pure water.
Explanation:
We have to cast our minds back to the idea of common ions effect. If any ion is already present in solution, the presence of that ion in solution prevents any solute containing a common ion with the solution from dissolving in that solution. In order words, the presence of a common ion makes a solute less soluble in a solvent than it is in pure water.
For instance, 0.10 M Ca(CH3COO)2 and K2SO3 both contain Ca^2+ and SO3^2- ions respectively which are also contained in the solute calcium sulfite.
The presence of these common ions in solution makes calcium sulfite less soluble in these solutions than it is in pure water because the equilibrium position for the dissolution of the solute lies towards the left hand side.
However, calcium sulfite is more soluble in 0.10 M NaNO3 than in pure water due to displacement reaction between the ions in solution.
The solubility of calcium sulfite and 0.10 M KCH3COO in pure water is quite comparable.
Which best expresses the uncertainty of the measurement 32.23 cm?
A.) ±0.05 cm
B.) 0.1 cm
C.) 1%
D.) ±0.01 cm?
Answer:
D.) ±0.01 cm?
Explanation:
Since 32.23 cm has two decimal places, the uncertainty is taken as one-half the last decimal pace.
The last decimal place is 0.03. Half of this is 0.03 cm/2 = 0.015 cm.
Since we cannot go below two decimal places, we ignore the 5 in 0.015 cm.
So, we have our uncertainty as 0.01 cm.
So, the best expression of the uncertainty in the measurement 32.23 cm is ± 0.01 cm.
So, the answer is D. which is ± 0.01 cm.
describe how lyophobic sols are synthesize by dispersion method
Explanation:
For preparing lyophobic sol, the substance in bulk is broken down into particles of colloidal dimensions (Dispersion) or aggregating smaller particles into particles of colloidal dimensions (condensation).
which effect of long-term environmental change is the driving force behind evolution?
Answer:
climate change
Explanation:
climate change is driving force of evolution because when the climate is changed the animal and human need to adapt to it's natural change.
g Suppose you are titrating vinegar, which is an acetic acid solution of unknown concentration, with a sodium hydroxide solution according to the equation H C 2 H 3 O 2 + N a O H ⟶ H 2 O + N a C 2 H 3 O 2 If you require 30.01 mL of 0.1798 M N a O H solution to titrate 10.0 mL of H C 2 H 3 O 2 solution, what is the molar concentration of acetic acid in the vinegar? Type answer:
Answer: The molar concentration of acetic acid in the vinegar is 0.539 M.
Explanation:
The formula used is:
[tex]M_1V_1=M_2V_2[/tex]
where,
[tex]M_1[/tex] and [tex]V_1[/tex] are the concentration and volume of base.
[tex]M_2[/tex] and [tex]V_2[/tex] are the concentration and volume of an acid.
Given:
Molar concentration of NaOH = 0.1798 M
Volume of NaOH = 30.01 mL
Volume of acetic acid = 10.0 mL
Now putting all the given values in the above formula, we get:
[tex]M_1V_1=M_2V_2\\\\0.1798M\times 30.01mL=M_2\times 10.0mL\\\\M_2=0.539M[/tex]
Thu, the molar concentration of acetic acid in the vinegar is 0.539 M.
Sodium is a highly reactive metal and
chlorine is a toxic gas, but when they
come together the resulting material,
sodium chloride, is essential for life.
Which of the following is true when
sodium and chlorine are brought into
contact with one another?
Answer:
NaCl
Explanation:
[tex]na + cl > nacl[/tex]
This is also a salt
What is the difference between a physical change and a chemical change. Give an example of each.
Answer:
A physical change is a change in form.
A Chemical change is a change in materials.
Explanation:
Example of a physical change would be an ice cube meting.
Example of a chemical change would be mixing food coloring into a cup of water.
Identify the isoelectronic elements.
i. Cl-, F-, Br-, I-, At-
ii. Ne, Ar, Kr, Xe, He
iii. N3-, S2-, Br-, Cs+, Sr2+
iv. N3-, O2-, F-, Na+, Mg2+
v. Li+, Na+, K+, Rb+,Cs+
Answer:
iv. N³⁻, O²⁻, F⁻, Na⁺, Mg²⁺
Explanation:
Isoelectronic elements are those that have the same number of electrons. So, if at least 2 elements differ in their number of electrons, the series is not of isoelectronic elements.
To know the number of electrons we will consider the atomic number and add electrons if it is an anion and subtract electrons it is a cation.
Identify the isoelectronic elements.
i. Cl⁻, F⁻, Br⁻, I⁻, At⁻. NO. Cl⁻ has 18 electrons (17+1) and F⁻ has 10 electrons (9+1). ii. Ne, Ar, Kr, Xe, He. NO. Ne has 10 electrons and Ar has 18. iii. N³⁻, S²⁻, Br⁻, Cs⁺, Sr²⁺. NO. N³⁻ has 10 electrons (7+3) and S²⁻ has 18 (16+2).iv. N³⁻, O²⁻, F⁻, Na⁺, Mg²⁺. YES. They all have 10 electrons v. Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺. NO. Li⁺ has 2 electrons (3-1) and Na⁺ has 10 (11-1).A tank at is filled with of sulfur tetrafluoride gas and of sulfur hexafluoride gas. You can assume both gases behave as ideal gases under these conditions. Calculate the mole fraction of each gas. Round each of your answers to significant digits.
The question is incomplete, the complete question is:
A 7.00 L tank at [tex]21.4^oC[/tex] is filled with 5.43 g of sulfur hexafluoride gas and 14.2 g of sulfur tetrafluoride gas. You can assume both gases behave as ideal gases under these conditions. Calculate the mole fraction and partial pressure of each gas. Round each of your answers to significant digits.
Answer: The mole fraction of sulfur hexafluoride is 0.221 and that of sulfur tetrafluoride is 0.779
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
For sulfur hexafluoride:Given mass of sulfur hexafluoride = 5.43 g
Molar mass of sulfur hexafluoride = 146.06 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of sulfur hexafluoride}=\frac{5.43g}{146.06g/mol}=0.0372mol[/tex]
For sulfur tetrafluoride:Given mass of sulfur tetrafluoride = 14.2 g
Molar mass of sulfur tetrafluoride = 108.07 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of sulfur tetrafluoride }=\frac{14.2g}{108.07g/mol}=0.1314mol[/tex]
Total moles of gas in the tank = [0.0372+ 0.1314] mol = 0.1686 mol
Mole fraction is defined as the moles of a component present in the total moles of a solution. It is given by the equation:
[tex]\chi_A=\frac{n_A}{n_A+n_B}[/tex] .....(2)
where n is the number of moles
Putting values in equation 2, we get:
[tex]\chi_{SF_6}=\frac{0.0372}{0.1686}=0.221[/tex]
[tex]\chi_{SF_4}=\frac{0.1314}{0.1686}=0.779[/tex]
Hence, the mole fraction of sulfur hexafluoride is 0.221 and that of sulfur tetrafluoride is 0.779
how many moles of neon gas have a volume of 0.84 L and a pressure of 4.6 atm at 222k
Answer:
n = 0.21 moles
Explanation:
Given that,
Volume, V = 0.84 L
Pressure, P = 4.6 atm
T = 222 K
We need to find the number of moles of Neon gas. We know that,
PV = nRT
Where
n is the number of moles
R i the gas constant, R = 0.08206 L-atm/mol-K
Put all the values,
[tex]n=\dfrac{PV}{RT}\\\\n=\dfrac{4.6\times 0.84}{0.08206 \times 222}\\\\n=0.21\ \text{moles}[/tex]
So, there are 0.21 moles of Neon gas.
A student named a particular compound 2-ethyl-3-methyl-2-butene. Assuming that the student's choice actually corresponded to the correct distribution of the double bond and the substituents, what is the correct IUPAC name for this compound
Answer:
2-ethyl-3-methylbut-2-ene
Explanation:
The whole idea of IUPAC nomenclature is to devise a universally accepted system of writing the name of a compound from its structure.
According to IUPAC nomenclature, the root of the compound is the longest carbon chain. The substituents are named in alphabetical order and in such a way as to give each one the lowest number. The position of the functional group is indicated accordingly.
For the compound in question, its correct IUPAC name is 2-ethyl-3-methylbut-2-ene.
What is the concentration of s solution that contains 55 mL of alcohol per 145 mL solution?
Answer:
37.9% v/v
Explanation:
Since both the alcohol and solution are presumed to be liquid, this concentration can be expressed as a volume concentration (or % v/v):
volume concentration = volume of solute / volume of solution
[tex]\% v/v = 55/145= 0.379[/tex]
During a chemical reaction, an iron atom became the ion Fe2+. What happened to the iron atom?
Explanation:
Iron atom is been oxidised as it losses 2 electron to form 2 + ion.
explain why seeing a gas doesn not always indicate that there was a chemical change.
How do we fix climate change?
The biggest problem of course is conspiracy theorys. Some say it is just a hoxe when really their chidrin or grandchidrin will sufer greatly from it. How do we educate ourselfs better?
Answer:
Hi so your answer is that to helping fix the climate change you have to : speak up , power your home with renewable engery , reduce water waste , dont waste food , and finally invest energy .
Explanation:
Really hope i helped , have a nice day :)
Answer:
we can reduce air pollution,which is one of the main cause of climate change.Climate change is not a hoxe if it is not attending the upcoming generations will suffer greatly.
Which of the following is considered a standard unit of length in the United States?
O square inch
O acre
O cubic yard
O yard
Answer:
Yard . I hope this helped:))
A 14.570 g sample of CaCl2 was added to 12.285 g of K2CO3 and mixed in water. A 3.494 g yield of CaCO3 was obtained.
What is the limiting reagent?
-CaCO3
-K2CO3
-CaCl2
Calculate the percent yield of CaCO3.
yield of CaCO3= %
Answer:
Limiting reagent is the potassium carbonate.
Percent yield of calcium carbonate is: 39.3 %
Explanation:
The reaction is:
CaCl₂ + K₂CO₃ → CaCO₃ + 2KCl
Formula for percent yield is:
(Produced yield / Thoeretical yield) . 100
Firstly we determine the moles of each reactant, in order to say what is the limiting reagent: ratio is 1:1.
1 mol of chloride need 1 mol of carbonate.
14.570 g . 1 mol /110.98 g = 0.131 moles of CaCl₂
12.285 g . 1 mol / 138.2g = 0.0889 moles of carbonate.
Limiting reagent is carbonate. For 0.131 moles of CaCl₂ we need the same amount of carbonate and we have less moles.
Ratio is also 1:1, with calcium carbonate.
1 mol of potassium carbonate produces 1 mol of calcium carbonate
then, 0.0889 moles will produce the same amount of CaCO₃
We convert moles to mass: 0.0889 mol . 100.08g /mol = 8.89 g
That's the theoretical yield; to find the percent yield:
(3.494 g / 8.89g) . 100 = 39.3%
What is the observation of heating of iodine crystals
Answer:
On heating, the van der Waals dispersion forces existing then will easily break as it has a low boiling point and sublimates into gas. On heating iodine in the test tube, iodine evolves as violet fuming gas.
Explanation:
A solution of KMnO4 has an absorbance of 0.539 when measured in the colorimeter. Determine the concentration of the KMnO4 given the following data for a calibration plot.
Concentration of KMNO4 (M) Absorbance
0.0150 0.081
0.0300 0.159
0.0450 0.260
0.0600 0.334
Answer:
Concentration of unknown solution is 0.0416 M
Explanation:
As we know
Absorbance is equal to the product of molar absorptivity of KMnO4 m, path length and concentration
From the given set of graphical data, it is clear that the absorbance vs concentration is a straight line.
From the graph, we can obtain-
Y = 5.73 X – 0.0065
Absorbance = 0.232
0.232 = 5.73 X – 0.0065
X = 0.0416
Concentration of unknown solution is 0.0416 M
The formula for europium oxide is Eu203. On the basis of this information, the formula for the chlorate of europium would be expected to be
Answer:
Eu(ClO3)3
Explanation:
The chlorate ion is written as follows, ClO⁻ ₃. We can see from this that the ion is univalent.
From the formula, Eu203, it is easy to see that the europium ion is trivalent.
Hence, when a compound is formed between the europium ion and chlorate ion, the compound will be written as Eu(ClO3)3.
This is so because, when ionic compounds are formed, there is an exchange of valence between the ions in the compound. This gives the final formula of the ionic substance.
What would happen to the Earth's hydrosphere if there were no atmosphere?
Predict the products from theses reaction, and balance the equations. Include phase symbols.
Reaction : K(s)+Cl2(g)⟶
Reaction :Cu(s)+O2(g)⟶
Answer:
2 K(s) + Cl₂(g) ⟶ 2 KCl(s)
2 Cu(s) + O₂(g) ⟶ 2 CuO(s)
Explanation:
Both reactions are synthesis reactions (two substances combine to form another).
Reaction: K(s) + Cl₂(g) ⟶
The product is the binary salt KCl. The balanced chemical equation is:
2 K(s) + Cl₂(g) ⟶ 2 KCl(s)
Reaction: Cu(s) + O₂(g) ⟶
The most likely product is the metal oxide CuO. The balanced chemical equation is:
2 Cu(s) + O₂(g) ⟶ 2 CuO(s)
A buffer solution contains 0.298 M ammonium chloride and 0.478 M ammonia. If 0.0560 moles of hydroiodic acid are added to 225 mL of this buffer, what is the pH of the resulting solution?
Answer:
pH = 8.87
Explanation:
Hydroiodic acid, HI, is a strong acid that reacts with ammonia, NH3, to produce ammonium ion, NH⁴⁺. That means the moles of HI added = moles of NH3 consumed and moles of NH4⁺ produced.
Initial moles NH₄⁺:
0.225L * (0.298mol/L) = 0.06705 moles
Initial moles NH3:
0.225L * (0.478mol/L) = 0.10755 moles
After the reaction the moles are:
0.10755moles NH3 - 0.0560moles = 0.05155 moles NH3
0.06705moles NH4+ + 0.0560moles = 0.12305 moles NH4+
Using H-H equation for weak bases:
pOH = pKb + log ([NH4+] / [NH3])
pKb for ammonia is 4.75, [NH4+] could be the moles of NH4+ = 0.12305mol,
[NH3] = 0.05155moles
Replacing:
pOH = 4.75 + log (0.12305mol / 0.05155moles)
pOH = 5.13
pH = 14-pOH
pH = 8.87You decide to share some sugar sweetened fruit juice with your friend. You divide the fruit equally into two glasses. Then an additional equal volume of water is added to glass 1. Which glass would have the lower molarity?
Answer:
Glass 1
Explanation:
Molarity is measured in moles of substance per liter.
For the sake of calculations, let's say that each glass contains 1 mole of juice and 1 liter after it is divided between the glasses. If you add an equal amount of water to glass 1 ( another liter), you now have:
Glass 1 = 1 mole / 2 liters = 0.5 M
Glass 1 = 1 mole/ 1 liter = 1 M
So glass 1 will have a lower molarity
