yall what do ya think shaped ya feelings bout science classes?
I was interested in science when I first saw a diagram of Solar system in my sister's geography book. At that time I was in Senior Kindergarten and she was in 6th grade. At first, I was just interested in space, universe and black holes stuff, but then as I started learning more, I realised how amazing other branches of science are too. They are so systematic. What encourages me to learn more are the gaps in science, its mysteries, I wish to uncover them one day, and for that I am preparing myself. When I am in a science class, I try to imagine where can I apply this knowledge in my day to day life, and my teachers are fascinated when I ask them if this principle is responsible for this phenomena. I love it very much. I like Physics the most, but other branches are great too.
22.5 ml of a 0.200 m HBr solution was added to a 50.00 ml sample of 0.250 m sodium benzoate (NaC7H5O2). Calculate the pH. Benzoic acid has a Ka 6.30 x 10-5.
In this problem, we need to find the pH of a buffer (pH = 4.45) that is produced by the reaction of strong acids as HBr that reacts with weak bases as NaC₇H₅O₂ producing its weak acid and a salt, as follows:
HBr + NaC₇H₅O₂ → HC₇H₅O₂ + NaBr
If in the reaction, the limiting reactant is the strong acid, we will produce a buffer (The aqueous mixture of a weak acid and its strong base).
Using Henderson-Hasselbalch equation, we can find the pH of this buffer:
[tex]pH = pKa + log \frac{[NaC_7H_5O_2]}{[HC_7H_5O_2]}[/tex]
Where:
pKa is -log Ka = 4.20
[] could be taken as the moles of each species
After the reaction, the moles of HBr = Moles of HC₇H₅O₂ and the remaining moles of NaC₇H₅O₂ = Initial moles of NaC₇H₅O₂ - Moles of HBr.
Moles HBr:
22.5mL = 0.0225L * (0.200mol/L) = 4.5x10⁻³ moles HBr
Moles NaC₇H₅O₂:
50.0mL = 0.0500L * (0.250mol/L) = 0.0125 moles NaC₇H₅O₂
That means the moles after the reaction of the species of the buffer are:
Moles HC₇H₅O₂ = Moles HBr = 4.5x10⁻³ moles
Moles NaC₇H₅O₂ = 0.0125 moles - 4.5x10⁻³ moles = 8.0x10⁻³ moles
Replacing in H-H equation:
[tex]pH = 4.20+ log \frac{[8.0x10^{-3}]}{[4.5x10^{-3}]}[/tex]
pH = 4.45
Learn more about Henderson-Hasselbalch equation in:
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3. An atom
OF
elemente A has mass number 39 and 19 protons
Write the electron arrangement of the atom
Answer:
Explanation:
Potassium (K) atom has 19 electrons. The full electron configuration of Potassium (K) is 1s22s22p63s23p64s1
Principal energy level
Quantum number: n
1
2
3
4
5
6
Sublevels
availableQuantum number: l
1s
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f 5g
6s 6p 6d 6f 6g 6h
What is the name for the compound li2so4
Answer:
Explanation:
Lithium Sulphate
Answer:
Lithium sulfate is a white inorganic salt with the formula Li2SO4. It is the lithium salt of sulfuric acid.
Which of the following describes scientists?
О
A. People with only one perspective
B. People with similar personalities
C. People from different backgrounds
D. People with perfect understanding of science
A sample of gas occupies 1.2 L at 12.0oC. Assuming pressure remains the same, what would be the volume (in L) of this gas at 67oC?
A.
1.4
B.
1.0
C.
0.2
D.
5.0
E.
6.7
Answer:
e.
6.7
hope it help
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What is the solubility of salt at 60°C if 2 gm of the salt is left behind when 7 gm of its saturated solution at that temperature dried?
a) 20
b) 40
c) 60
d) 80
40
Explanation:
because its Saturated
Potassium impart purple colour but beryllium do not impart any colour to the flame.Why?
Answer:
The electrons in beryllium and magnesium are too strongly bound to get excited by flame. Hence, these elements do not impart any color.How can the percentage of air be determined
Answer:
The composition of air can be determined by an experiment which includes passing a known volume of air, measured at a known temperature and pressure, over sufficient amount heated copper granules/powder, and measuring the volume gas remaining after the gas cools down to the temperature at which the first measurement was taken
Oxygen reacts with copper according to the following chemical reaction
2Cu (s) + O₂ (g) → 2CuO (s)
Cupper does not react with the other constituents of air
Whereby the initial volume of air was 100 cm³, we have;
Percentage of oxygen in air = 100 - The final volume reading of the container initially holding the air
When done using am appropriate experimental setup, the percentage of gases remaining equals 79% to 80%, therefore, the percentage composition of oxygen in air is between 20 and 21 percent
Explanation:
can you solve this science question ⁉️
Answer:
chemical reaction between those a b c it's a reaction which occurs when heating
Chemistry!! Help me! And explain step by step!
1st part is ure answer --> 2M
Given mass -> 58 grams
mass of NaCl -> 58.44 approx -> 58 any
moles given-> 1 moles
[tex]Molarity = \frac{moles}{vol \: in \: lts} [/tex]
[tex]Molarity = \frac{1}{0.5} = \frac{10}{5} \\Molarity = 2M[/tex]
what is precipitating ???
anyone please tell me how to delete an I'd
Explanation:
Desposition of solid matter in a solution
what is the product of SO2+H2O.
Answer:
H2O + SO2 → H2SO3
Explanation:
H2O + SO2 → H2SO3
Answer:
l think this is the answer .
Mike is gathering equipment for a lab where he will measure the masses of various
chemicals. Which of the following is the most complete list of the equipment he will
need?
electric balance, graduated cylinder, test tube
graduated cylinder test tube, goggles
O graduated cylinder beaker, test tube
electric balance, goggles, beaker
Answer:
electric balance, goggles, beaker
Explanation:
I did it and got it right
A new stable element with an atomic number of 120 and an atomic mass of 246 is created in a particle accelerator. Enough of this element is created to determine that it combines with chlorine in a 1:2 ratio. Element 120 should be placed in the same group as _____ on the periodic table.
Answer:
Be,Mg,Ra etc
Explanation:
It should be palced in group 2A because as it reacts with chlorine in ratio of 1:2 . It's valancy is 2 and is metal as it react with non metal donating two electrons .
one more thing it fits there orderly
please answer this questions soon
i will mark him or her brillient
Answer:
1)Or
d.Sublimation
2)
b.iodine is the solute and alcohol is solvent
3)
a.compostion of solute
Answer:
1) a) centrifugation
OR
b) sublimation
2) a) iodine is the solute and alcohol is solvent
3) a) concentration of soLute
Which of the following is a scientific question you could ask about the game
of basketball?
A. Do you enjoy basketball more than volleyball?
B. Which team is this year's best?
C. Which player should be traded to another team?
D. Do teams that practice more win more games?
SUBMIT
The scientific question related to the game of basketball is option D: "Do teams that practice more win more games?"
This question is scientific because it explores a cause-and-effect relationship between practice and game outcomes. It can be investigated through empirical observation and data analysis.
To answer this question, researchers could collect data on the practice hours of different basketball teams and compare them to their corresponding game performance. Statistical analysis could be used to determine if there is a correlation between practice time and winning percentage or other performance metrics.
By examining a large sample of teams over an extended period, researchers could draw conclusions about the impact of practice on game outcomes. This scientific inquiry would contribute to the understanding of the factors that influence team success in basketball and could potentially inform training strategies and coaching techniques.
For more question on basketball
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Câu 9: 100 g dung dịch MgCl2 9.5 % tác dụng đủ với dung dịch KOH 5,6 % .được dung dịch A và chất rắn B. Lọc rắn B và nung đến khối lượng không đổi được chất C.
a) Viết pt .Tính khối lượng răn C
b) Tính nồng độ phân trăm của dung dịch A.
hiiiiiiiii
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Some species form social groups only with members of the same gender. For example, elephants form groups with
only females and their offspring. Once the male offspring reach a certain age, they leave the group and become
solitary.
Which is a benefit of this type of social group structure?
Explanation:
For example, elephants form groups with only females and their offspring. Once the male offspring reach a certain age, they leave the group and become solitary. Which is a benefit of this type of social group structure? A:Females do not have to compete for a mate.
Which type of monomer combines and forms nucleic acids?
A. Nucleotide
B. Nitrogenous base
C. Amino acid
D. Monosaccharide
Answer:
A. Nucleotide
Explanation:
Nucleotides are the monomers that make up nucleic acids, such as DNA and RNA.
3. What would be the freezing point for a 5.7 molal aqueous sucrose (C12H22O) solution? The freezing
point depression constant for water = 1.86°C/m. Show your work.
Answer:
- 10.6° C
Explanation:
Given that,
In the aqueous sucrose solution,
Molality of the solution (m) = 5.7
Freezing point constant (K) = 1.86
To find,
The freezing point of the solution = ?
Method:
To find its freezing point, we will first find out if the solute demonstrates an electrolyte or not.
In case it is not, the van't Hoff factor i.e. ration of particles' concentration denoted by (i) would be taken as 1. So,
ΔT(change in temperature) = i * m * K (putting the given values)
= 1 * 5.7 * 1.86
= 10.6° C
Thus, the freezing point equals to 0 - 10.6° C = -10.6° C.
A scientist claims that the water molecules that you drink today could be millions of years old. Use evidence from the water cycle to support the scientist’s claim.
Answer:
As water on the surface of lakes, oceans, and rivers warms up, it travels into the sky as very tiny droplets, or vapor. When the water vapor gets colder, it turns back to liquid to help form clouds.
When the liquid gets so heavy it can’t stay in the atmosphere anymore, it falls, or “precipitates,” as rain, snow, sleet, hail, or, my favorite, graupel. Once the precipitation reaches the ground or lands in lakes, oceans, and rivers, the cycle continues.
Explanation:
A scientist claims that the water molecules that you drink today could be millions of years old in the water cycle the new clouds athat re made cannot rain but the clouds which are old do rain.
What is the water cycle?The water cycle or cycle of water is the journey of each and every water molecule by which it is made up of as the clouds in the environment are made up of the evaporation process in the environment.
The vapors of evaporation condense in the environment to form the clouds and these clouds are only responsible for the rain but the old and heavy clouds can only do it.
Therefore, in the water cycle, the new clouds are made cannot rain but the clouds which are old do rain scientist claim that the water molecules that you drink today could be millions of years old.
Learn more about the water cycle, here;
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Suppose you had a valuable collection of small diamonds, which you kept safe from the thieves by mixing them with white sugar crystals. You store the mixture in a jar labeled 'sugar'. Now you want to sell the diamonds. Describe how you would separate all the diamonds from the sugar.
Answer:
Pour the sugar/diamond mixture into a container of water and stir until the sugar is dissolved completely. Then strain the mixture and wash the diamonds with water.
Answer:
Stir with a large enough volume of cold water to dissolve all the sugar. Filter to leave the diamonds on the filter paper. Wash on the filter paper with more water to remove any last traces of sugar solution. Allow to dry.
PLZ HELP ME WITH MY WORK
What is a compound?
A substance that is made from two different metals
B. A substance that cannot be broken into simpler substances
C. A substance that is made using a chemical reaction
D. A substance that can be separated by physical means
Answer:
C.
Explanation:
Answer A is incorrect because a compound doesn't have to be made with only metals.
Answer B is incorrect because that is actually the definition of a pure element.
Answer C is correct because to make a compound, there has to be a chemical reaction where bonds are formed and an entirely new substance is created.
Answer D is incorrect because compounds cannot be separated by physical means.
Hope this helps :D
A cactus needle is a structure made of different tissues that work together to protect the plant from animals that might want to eat it. What level of body organization does a cactus needle represent?
A. Cell
B. Organ
C. Cell system
D. Body system SUBMIT
which of the following will show tyndall effect ?
a. salt solution
b. copper sulphate solution
c. starch solution
d. chalk powder in water
Answer:
Starch solution
Explanation:
Colloidal solutions show tyndall effect and starch solution is a colloidal solution.
hii pls help me to balance the equation thanksss
Explanation:
2KCLO3 (s) = 2KCl (s) + 3O2 (g)
Uranium-235 and uranium-238 are different ________ of uranium
(Apx answers please)
Answer:
Isotopes
Explanation:
An isotope are the atoms of an element with similar chemical identity and number of protons but different atomic masses. This means that isotopes of an element differ from one another by their number of NEUTRONS.
For example, the uranium element possesses isotopes as follows: Uranium-235 and uranium-238. This two isotopes have the same chemical identity and number of protons/atomic no., which is 92. However, the atomic masses (235 and 238) are different.
Answer:
Isotopes
Explanation:
Convert the following moles to grams :)
1. 2.4 moles sulfur
2. 1.5 moles BeI2
3. 7.5 moles C6H12O6
Answer:
3
Explanation:
sky is high and I am good.
Do plants need soil to grow
Answer:
Not all plants do need soil to grow
Explanation:
Not all plants need soil to grow. Some just do better in soil compared to other growing mediums. What plants need are minerals and nutrients, such as nitrogen, potassium, and phosphorous. Soil is an effective way of delivering those nutrients cost-effectively. You can also use alternative delivery systems like hydroponics, aeroponics, and aquaponics to achieve the desired effect. However, these are only suitable for growing shallow-rooted plants. Plants with deep roots will always need soil, as will larger plants with spreading roots.
