Answer:
somebody small boy is not w e a r d
z0 0m = 257 473 5835 p c:- 12 34
Which of the following two periods contain the same number of element?
A. 2 & 3
B.3 & 4
c. 4 & 6
D. 2 & 4
Answer:
4 and 6
Explanation:
Period 4 has 18 elements and so does period 6.
An unknown weak acid with a concentration of 0.530 M has a pH of 5.600. What is the Ka of the weak acid
Answer:
Ka = 3.45x10⁻⁶
Explanation:
First we calculate [H⁺], using the given pH:
pH = -log[H⁺][H⁺] = [tex]10^{-pH}=10^{-5.6}[/tex] [H⁺] = 2.51x10⁻⁶ MTo solve this problem we can use the following formula describing a monoprotic weak acid:
[H⁺] = [tex]\sqrt{C*Ka}[/tex]We input the data that we already know:
2.51x10⁻⁶ = [tex]\sqrt{0.530*Ka}[/tex]And solve for Ka:
Ka = 3.45x10⁻⁶A chemist makes of nickel(II) chloride working solution by adding distilled water to of a stock solution of nickel(II) chloride in water.Calculate the concentration of the chemist's working solution. Round your answer to significant digits.
Answer:
0.0900 mol/L
Explanation:
A chemist makes 330. mL of nickel(II) chloride working solution by adding distilled water to 220. mL of a 0.135 mol/L stock solution of nickel(II) chloride in water. Calculate the concentration of the chemist's working solution. Round your answer to significant digits.
Step 1: Given data
Initial concentration (C₁): 0.135 mol/LInitial volume (V₁): 220. mLFinal concentration (C₂): ?Final volume (V₂): 330. mLStep 2: Calculate the concentration of the final solution
We prepare a dilute solution from a concentrated one. We can calculate the concentration of the working solution using the dilution rule.
C₁ × V₁ = C₂ × V₂
C₂ = C₁ × V₁/V₂
C₂ = 0.135 mol/L × 220. mL/330. mL = 0.0900 mol/L
Balance the chemical equation below using the smallest possible whole number stoichiometric coefficients.
P4(s) + NaOH(aq) + H2O(l) -> Ph3(g) + Na2HPO3(aq)
Answer:
I used a,b c, d in the equation as substituted coefficients to find the unknown for each element of P, Na, O, H, and I got
P4(s) + 4NaOH(aq) + 2H20(l)---->2Ph3 +2Na2HPO3(aq).
which I think should be the answer.
Choose the correct statement. A) The cathode is the electrode where the oxidation takes place. B) The cathode is the electrode where the reduction takes place. C) Both oxidation and reduction may take place at the cathode, depending on the cell. D) The cathode is always positive
Define mass number of an atom.
A chemist measures the energy change
ΔH during the following reaction:
2NH3(g)→N2(g)+3H2(g)
ΔH=160kJUse the information to answer the following questions.This reaction is:__________.
a. endothermic
b. exothermic
Suppose 70.9 g of NH3 react. Will any heat be released or absorbed?
a. Yes, absorbed
b. Yes, released
c. No.
If you said heat will be released or absorbed in the second part of this question, calculate how much heat will be released or absorbed. Round your answer to 3 significant digits.
Answer:
For (1): The correct option is (a)
For (2): The correct option is (a) and 333.6 kJ of heat will be absorbed when 70.9 g of ammonia reacts.
Explanation:
There are 2 types of reactions that are classified based on enthalpy change:
Endothermic reactions: These are the reactions where heat is absorbed by the reaction. The change in enthalpy of the reaction, [tex]\Delta H_{rxn}[/tex] is positive for these reactions.
Exothermic reactions: These are the reactions where heat is released by the reaction. The change in enthalpy of the reaction, [tex]\Delta H_{rxn}[/tex] is negative for these reactions.
For (1):For the given chemical reaction:
[tex]2NH_3(g)\rightarrow N_2(g)+3H_2(g);Delta H=160kJ[/tex]
As the change in enthalpy or heat of the reaction is positive. Thus, the reaction is an endothermic reaction because heat is absorbed by the reaction.
For (2):When ammonia reacts, some amount of heat will be absorbed by the reaction. Thus, we can say the heat will be absorbed.
The number of moles is calculated by using the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
Given mass of ammonia = 70.9 g
Molar mass of ammonia = 17 g/mol
Using equation 1:
[tex]\text{Moles of ammonia}=\frac{70.9g}{17g/mol}=4.17mol[/tex]
By stoichiometry of the reaction:
If 2 mole of ammonia reacts, the heat absorbed is 160 kJ
So, if 4.17 moles of ammonia reacts, the heat absorbed will be = [tex]\frac{160kJ}{2mol}\times 4.17mol=333.6kJ[/tex]
Hence, 333.6 kJ of heat will be absorbed when 70.9 g of ammonia reacts
Determine whether methylcyclohexane contains a chiral center. _____ How many different substituents do you count at atom
Answer:
methylcyclohexane does not possess a chiral center
Explanation:
A molecule is said to possess a chiral center if one or more of the atoms in the molecule is bonded to four different atoms or groups.
If we look at methylcyclohexane, none of the carbon atoms in the molecule is bonded to four different atoms or groups hence the molecule contains no chiral centers and will not exhibit optical isomerism.
So, methylcyclohexane has a plane of symmetry thus it is an achiral molecule.
A 1.19 g sample of an unknown halogen occupies 109 mL at 398 K and 1.41 atm. What is the identity of the halogen
Answer:
The halogen is Iodine.
Explanation:
Using the ideal gas equation, we find the number of moles of gas present, n.
PV = nRT where P = pressure of gas = 1.41 atm, V = volume of gas = 109 mL = 0.109 L, n = number of moles of gas, R = molar gas constant = 0.082 L-atm/mol-K and T = temperature of gas = 398 K
Since PV = nRT, making n subject of the formula, we have
n = PV/RT
substituting the values of the variables into the equation, we have
n = 1.41 atm × 0.109 L/(0.082 L-atm/mol-K × 398 K)
n = 0.15369 atm-L/32.636 L-atm/mol
n = 0.0047 mol
Since n = m/M where m = mass of gas = 1.19 g and M = relative molecular mass of gas
So, M = m/n
M = 1.19 g/0.0047 mol
M = 252.7 g
Since halogens are diatomic the relative atomic mass is M/2 = 252.7g/2 = 126.34 g
From tables, the only halogen with this atomic mass is Iodine.
So, the halogen is Iodine.
1. What is the difference between accidental discoveries and scientific investigations?
Answer:
the discovery will always need to be tested more where if you're investigating you should already be in a more controlled environment
The difference between accidental discoveries and scientific investigations are as follows.
Accidental discoveriesThe discovery which is occur accidentally, means something discovered intensely.Examples of accidental discoveries like, microwave, teflon, penicillin, plastic etc.Scientific investigationA process of finding of answers of the question by using various research method.There are various scientific investigation, like fair testing, modeling, pattern, seeking, identification and classifying etcExample of scientific investigation are plant experiment.To learn more about accidental discoveries,
https://brainly.com/question/13167222
#SPJ2
Calculate the number of ATOMS in 1.0 mole of O2. blank x 1024
Answer:
6.023*10^23........ .......
help with the following would be greatly appreciated!
6. Which compound contains no ionic character?
Answer:
The compound which doesn't contains ionic character is HC, H-atom and CL- atom shares 1 electron a to form covalent bond....
once a recrystallization is completed and filtered, what solvent would be suitable for transferring the leftover solids to filtration funnel
Answer:
To transfer leftover solids to the filtration funnel and wash out crystals after recrystallization, ice cold methanol should be used (the mother liquor used for recrystallization).
Explanation:
Hope this helped
What is different between margerine and butter in term of organic chemistry
Answer:
The most important difference between the two is that butter is derived from dairy and is rich in saturated fats, whereas margarine is made from plant oils. ... If the margarine contains partially hydrogenated oils, it will contain trans fat, even if the label claims that it has 0 g.
Explanation:
(⌒_⌒;)
What types of house are found in very cold regions
Answer:
the house found in a very cold are Igloos or the ice house
Rank the following chemical species from lowest absolute entropy (So) (1) to highest absolute entropy (5) at 298 K?
a. Al (s)
b. H2O (l)
c. HCN (g)
d. CH3COOH (l)
e. C2H6 (g)
Answer:
Rank the following chemical species from lowest absolute entropy (So) (1) to highest absolute entropy (5) at 298 K?
a. Al (s)
b. H2O (l)
c. HCN (g)
d. CH3COOH (l)
e. C2H6 (g)
Explanation:
Entropy is the measure of the degree of disorderness.
In solids, the entropy is very less compared to liquids and gases.
The entropy order is:
solids<liquids<gases
Among the given substances, water in liquid form has a strong intermolecular H-bond.
So, it has also less entropy.
Next acetic acid.
Between the gases, HCN, and ethane, ethane has more entropy due to very weak intermolecular interactions.
HCN has slight H-bonding in IT.
Hence, the entropy order is:
Al(s) < CH3COOH (l) <H2O(l) < HCN(g) < C2H6(g)
Would 1 pound of peanut butter occupy more or less space than 1 pound of water?
4. If matter goes through a chemical change, are the physical properties likely to stay the same?
•
Please say yes or no and explain why.
Answer: If matter goes through a chemical change then the physical properties are not likely to stay the same.
Explanation:
When chemical composition of a substance changes during a chemical reaction then it is called a chemical change.
Chemical change always leads to the formation of new substances. Properties like chemical reactivity, combustion, rusting etc are chemical changes.
For example, [tex]N_{2} + 3H_{2} \rightarrow 2NH_{3}[/tex]
Here, [tex]NH_{3}[/tex] will have different chemical as well as physical properties as compared to [tex]N_{2}[/tex] and [tex]H_{2}[/tex].
As physical properties are the properties that cause change in state of a substance.
Properties like boiling point, state of substance etc are physical properties.
Thus, we can conclude that if matter goes through a chemical change then the physical properties are not likely to stay the same.
following this list of common polyatomic ions what would be the charge for aluminum nitrate?
Nitrate NO3
Phosphate PO43,
Sulfate SO4 -2
acetate C2H3O2-1
Ammonium NH4.
Chromate CrO4-2
Carbonate C03-2
Dichromate CrO7-2
Permanganate MnO4-1
What would be the correct answer for Aluminum nitrate
Answer:
Nitrate NO3
here's your answer, hope it helps you
When 2-methyl-3-hexene is treated with Cl2 in methanol, three products are formed (neglecting stereoisomers). Draw curved arrows to show the movement of electrons in this step of the reaction mechanism.
Answer:
Explanation:
The structural formula of 2-methyl-3-hexene is drawn in the attached image below. After then, the three possible structures were drawn and the mechanism reaction.
From the mechanism shown, methanol deprotonates methoxide proton and neutralizes the positive charge to form methoxide. This is followed by the movement of electrons that takes place from the region of higher electron density to lower electron density.
Use the heating curve of 60.0 grams of ice and the list of values to answer the question.
A heating curve with the y -axis showing temperatures between -20 degrees Celsius and 15 degrees Celsius and the x-axis showing time. The plot starts at Point A at -20 degrees Celsius and moves diagonally upward and to the right until it reaches Point B, which measures 0 degrees Celsius. Next, the line runs horizontally to the right until it reaches Point C. From Point C the line moves up and to the right to Point D, which measures at 15 degrees Celsius.
© 2019 StrongMind
specific heat of ice = 2.10 J/(g·°C)
specific heat of water = 4.18 J/(g·°C)
specific heat of water vapor = 2.07 J/(g·°C)
latent heat of fusion of ice = 333.4 J/g
latent heat of vaporization of water = 2256 J/g
How much energy was added to the ice between Point A and Point D?
25 kJ
150 J
154 J
26 kJ
Answer:
Changes of state occur at segment
✔ B–C
and segment
✔ D–E
Explanation:
got it right on edge :)
The amount of energy added to the ice between Point A and Point D is approximately 25 kJ.
To calculate the amount of energy added to the ice between Point A and Point D, we need to consider the different stages of the heating curve.
Heating the ice from -20°C to 0°C:
The energy required to raise the temperature of the ice can be calculated using the specific heat of ice (2.10 J/(g·°C)) and the mass of the ice (60.0 g). The temperature change is from -20°C to 0°C, which is a total of 20 degrees.
Energy = mass × specific heat × temperature change
Energy = 60.0 g × 2.10 J/(g·°C) × 20°C
Energy = 2520 J
Melting the ice at 0°C:
The energy required to melt the ice can be calculated using the latent heat of fusion of ice (333.4 J/g) and the mass of the ice (60.0 g).
Energy = mass × latent heat of fusion
Energy = 60.0 g × 333.4 J/g
Energy = 20,004 J
Heating the water from 0°C to 15°C:
The energy required to raise the temperature of the water can be calculated using the specific heat of water (4.18 J/(g·°C)) and the mass of the water (60.0 g). The temperature change is from 0°C to 15°C, which is a total of 15 degrees.
Energy = mass × specific heat × temperature change
Energy = 60.0 g × 4.18 J/(g·°C) × 15°C
Energy = 3753 J
The total energy added to the ice between Point A and Point D is the sum of the energy calculated in each step:
Total Energy = Energy (Heating ice) + Energy (Melting ice) + Energy (Heating water)
Total Energy = 2520 J + 20,004 J + 3753 J
Total Energy = 25,277 J
Converting this energy to kilojoules (kJ):
Total Energy = 25,277 J ÷ 1000
Total Energy = 25.277 kJ
Therefore, the amount of energy added to the ice between Point A and Point D is approximately 25 kJ.
To know more about energy
https://brainly.com/question/1932868
#SPJ2
Determine whether each phrase describes carboxylic acids or esters.
a. Usually have a sour odor _____________
b. Notable for their pleasant fragrances ___________
c. Do not form hydrogen bonds amongst themselves and have higher vapor pressure _____________
d. Their reactions with base are known as neutralizations ____________
e. Their reactions with base are known as saponifications _____________
HELP ME PLEASE!!!!!!
I WANT IT AS PARAGRAPHHHHH NOT POINT AND ANSWER THIS TWO QUESTIONS AS 1 PARAGRAPH
One of the lab safety rules being violated is that Jodi doesn't have her hair tied up. She should have her hair tied up. Having her long hair not tied up or away from her face is a safety hazard. Jodi is also not wearing glasses, which is essential when working with chemicals. One of the Bunsen Burners aren't being used but it's on, which is a fire hazard.
Answer:
Jodi should wear her hair up to avoid a mishap, such as lighting her hair on fire. Then, instead of using a fire extinguisher on Jodi, Kimberly should use a fire blanket to prevent additional damage. Mac is preoccupied with a second flame and maybe Jodi without her safety goggles?
Calculate the molality of a solution containing 22.75 g of glycerol (C3H8O3) in 79.6 g of ethanol (C2H5OH).
Answer:
3.11 mol/kg
Explanation:
Molality M = number of moles of solute, n/mass of solvent, m
To calculate the number of moles of glycerol (C₃H₈O₃) in 22.75 g of glycerol, we find its molar (molecular) mass, M',
So, M' = 3 × atomic mass of carbon + 8 × atomic mass hydrogen + 3 × atomic mass of oxygen
= 3 × 12 g/mol + 8 × 1 g/mol + 3 × 16 g/mol = 36 g/mol + 8 g/mol + 48 g/mol = 92 g/mol.
So, number of moles of glycerol, n = m'/M' where m' = mass of glycerol = 22.75 g and M' = molecular mass of glycerol = 92 g/mol
So, n = m'/M'
n = 22.75 g/92 g/mol
n = 0.247 mol
So, the molality of the solution M = n/m
Since m = mass of ethanol = 79.6 g = 0.0796 kg, substituting the value of n into the equation, we have
M = 0.247 mol/0.0796 kg
M = 3.11 mol/kg
So, the molality of the solution is 3.11 mol/kg.
What does Gibbs free energy predict?
A. It predicts what the rate of the reaction will be.
B. It predicts how high the activation energy is.
C. It predicts if entropy will increase or decrease.
D. It predicts whether or not a reaction will be spontaneous.
Answer:
It predicts whether or not a reaction will be spontaneous.
Explanation:
The equation;
∆G= ∆H - T∆S enables us to obtain the Gibbs free energy of a chemical process.
The Gibbs free energy value tells us whether a chemical process will be spontaneous or not.
When;
∆G>0 the reaction is not spontaneous
∆G=0 the reaction is at equilibrium
∆G<0 the reaction is spontaneous
A buffer is prepared containing 0.75 M NH3 and 0.20 M NH4 . Calculate the pH of the buffer using the Kb for NH3. g
Answer:
pH=8.676
Explanation:
Given:
0.75 M [tex]NH_{3}[/tex]
0.20 M [tex]NH_{4}[/tex]
The objective is to calculate the pH of the buffer using the kb for [tex]NH_3[/tex]
Formula used:
[tex]pOH=pka+log\frac{[salt]}{[base]}\\[/tex]
pH=14-pOH
Solution:
On substituting salt=0.75 and base=0.20 in the formula
[tex]pOH=-log(1.77*10^{-5})+log\frac{0.75}{0.20}\\ =4.75+0.5740\\ =5.324[/tex]
pH=14-pOH
On substituting the pOH value in the above expression,
pH=14-5.324
Therefore,
pH=8.676
Which mechanisms is most significant in returning the ion concentrations to the resting state?
Answer:
Active transport by the Na+-K+ pump
Explanation:
Active transport by the Na+-K+ pump
Maintenance (and restoration) of the resting ion concentrations depends on the Na+-K+ pump. Once gated ion channels are closed, the combined action of the pump and ion leakage (particularly that of K+) establishes a resting membrane potential in a typical neuron of around âˆ'70 mV.
Imagine you are celebrating a birthday in December and need balloons. The temperature in the
store where you are purchasing the balloons is approximately 25°C and each balloon is filled
to a volume of 2 liters to obtain maximum pressure.
Use the gas laws to explain what will happen to the volume and pressure of the gas in the
balloon when go outside, where the temperature is 0°C. Include both Charles's Law
and Gay-
Lussac's Law in your answer.
ILL GIVE BRAINIEST PLEASE HELP
Using the following reaction:
H2SO4 (aq) + 2NaOH (aq) → Na2SO4 (aq) + 2H2O (l)
Calculate the molarity of the H2SO4 solution if 14.92 mL of NaOH was necessary to reach the endpoint of a titration. The molarity of the NaOH solution was 0.83 M and 25.18 mL of H2SO4 was added to the Erlenmeyer flask.
Answer:
The molar concentration of the H₂SO₄ solution is 0.28 M
Explanation:
Molar concentration = number of moles / volume in litres
Number of moles = molar concentration × volume
From the equation of reaction, molar ratio of acid to base = 1 : 2
Using the formula; Na/Nb = CaVa/CbVb
Where Na is the number of moles of acid; Nb = number of moles of base; Ca = concentration of acid; Va = volume of acid; Cb = concentration of base; Vb = volume of base; Na/Nb = mole ratio of acid to base
Substituting the given values in the equation:
1/2 = Ca × 25.18 / 0.93 × 14.92
Ca = 0.93 × 14.92/ 25.18 × 2
Ca = 0.28M
Therefore, the molar concentration of the H₂SO₄ solution is 0.28 M
