The element having 8 valence electrons and 4 energy levels is krypton, (Kr) it is a noble gas included in 18th group.
What is krypton?Krypton is 36th element in periodic table with main shell electronic configuration, K= 2, L= 8, M= 18 and N= 8 where, K, L, M and N are energy levels.
Krypton is in the group noble gases also called inert gases. The group members of Kr are, Helium, argon and xenon. Thus krypton is the element with 4 energy levels and 8 valence electrons.
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2. What properties do all acids have?
3. Why should you never use taste as a method for testing an unknown substance?
4. What is used to detect the presence of acids?
10. What can you use to detect the presence of a base?
11. What are some common bases that we use every day?
12. How does an antacid help reduce heartburn?
13. What happens when acid and base are mixed
14. What is used to determine the pH of a substance?
15. Describe how the pH scale works. In other words, what is it actually measuring?
17. Why is pH important to our environment?
18. Describe how salt is formed.
Pls help!!!!!
TIMED CHEMISTRY PLZ HELP How many selenium atoms are in the chemical formula for the compound formed when selenium is combined with lead(II)?
Answer: Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal with properties that are intermediate between the elements above
Explanation:
Why should a hypothesis be testable?
A. It must be testable in order to be found true or false.
B. It must be testable for the outcome to be predictable.
C. It must be testable for other scientists to consider it reliable.
D. It must be testable if it is to become a scientific theory.
secondary alcohol (X) reacts with PCL5 to give alkyl halide (Y) which on dehydrohalogenation yield an alkene(Z).The alkene upon ozonolysis gives the mixture of ethanal and methanal.Identify X ,Y ,Z
Answer:
X = 2-propanol
Y = 2-chloropropane
Z = propene
Explanation:
Secondary alcohol is an alcohol in which the carbon that the functional group (OH group) is attached to is also attached to two alkyl group. Examples are 2-propanol and 2-butanol.
The secondary alcohol referred to in the question here is 2-propanol and it reacts with PCl₅ as seen below
H₃C-CH-CH₃ + PCl₅ ⇒ H₃C-CH-CH₃ + HCl + POCl₃
| |
OH Cl
The alkylhalide produced there is 2-chloropropane. Thus, we can see that X is 2-propanol and Y is 2-chloropropane.
When this 2-chloropropane undergoes dehydrohalogenation (removal of hydrogen and halogen) an alkene is formed. The reaction is seen below
H₃C-CH-CH₃ (-HCl) ⇒ H₃C-CH=CH₂
|
Cl
The alkene produced (as seen above) is propene.
Confirmation: When propene undergoes ozonolysis, the compounds produced are ethanal and methanal as seen in the equation below
O
/ \
H₃C-CH=CH₂ + O₃ ⇒ H₃C - CH CH₂ [-O] ⇒ CH + CH₂
|| || || ||
O O O O
The final products as seen above are methanal and ethanal
A student made 50g of sodium acetate , 20g of water and 15g of carbon dioxide by reacting baking soda with vinegar. How many total grams of baking soda and vinegar did the student react?
Answer:
Reacting of 5 cm3 of baking soda with 100 cm3 of vinegar should produce 0.083 moles of CO2 gas, 0.083 moles of sodium acetate, and leave 0.01 moles of sodium bicarbonate unreacted.
Explanation:
HELP!!!
i will mark brainliest
Answer:
Blank #1: noble gas
Blank #2: bonding
Blank #3: octet rule
Blank #4: share
Blank #5: filled
Blank #6: halogen
Please give me brianliest!!
Can someone help? Ill give brainliest!
Directions: count each side of the reaction. Circle yes or no if it follows the law of conservation of mass
Answer:
Yes, it becomes 2 of H20 which is water
3. Does the siren of a moving police car seem to change pitch to the
police officers inside the car? Why or why not?
Answer:
As the police car moves towards them, the pitch of the police car's siren goes up because the sound waves get closer together in front of the police car. When the police car moves away from the person, the pitch goes down because the waves spread out behind the police and that makes the frequency go down.
Explanation:
Substance A dissociates 100% in water to produce H3O+ ions while substance B dissociates 25% in water to produce OH- ions. What can be determined from this information?
A:Substance A is a strong acid and substance B is a weak base
B:Substance A is a weak acid and substance B is a strong base
C:Substance A is a strong base and substance B is a weak acid
D:Substance A is a weak base and substance B is a strong acid
Answer:
A:Substance A is a strong acid and substance B is a weak base
Explanation:
From this information, we can conclude that substance A is a strong acid and substance B is a weak base.
A strong acid is one that ionizes completely in solution. Most strong acids are usually concentrated. 100% dissociation is a complete ionization.
A weak base ionizes slightly in an aqueous solution. 25% dissociation is weak ionization.
Answer:
a
Explanation:
Please help!!!! This equation is balanced: CaCO3 - CaO + CO2
True
False
If all objects masses are the same, then the object with the least ___ is the densest?
Possible Answers:
A: Mass
B: Volume
C: Weight
D: Density
Answer:
its weight
Explanation:
mass is how much space it takes up the volume stays the same density is what happens after so its weight
a balloon initially has 0.40 liters and a temperature of 20°C what will the volume of the balloon be after it heats to 250°C
Answer:
0.7L
Explanation:
Given parameters:
Initial volume V₁ = 0.4L
Initial temperature T₁ = 20°C = 20 + 273 = 293K
Final temperature = 250°C = 250 + 273 = 523K
Unknown:
Final volume V₂ = ?
Solution:
To solve this problem, we apply Charles's law.
It states that "the volume of a fixed mass of a gas varies directly as the absolute temperature if the pressure is constant".
mathematically;
[tex]\frac{V_{1} }{T_{1} } = \frac{V_{2} }{T_{2} }[/tex]
V and T are temperature values
1 and 2 are initial and final states;
Insert the parameters and solve;
[tex]\frac{0.4}{293}[/tex] = [tex]\frac{V_{2} }{523}[/tex]
V₂ = [tex]\frac{523 x 0.4}{293}[/tex] = 0.7L
Three friends were kicking soccer balls at a neighborhood field. Three soccer balls were rolling across the field. The black soccer ball has less mass than the blue and orange balls, which have equal mass. All three soccer balls were kicked by one of the friends, but not all from the same direction. Use the information in the diagram to answer.
Which soccer ball(s) experienced the strongest force? How do you know?
A. All three soccer balls experienced the same force because they changed speed by the same amount.
B the orange soccer ball it has more mass and the fastest ending speed
c. the blue soccer ball it takes a stronger force to slow down a more massive object than to speed it up.
D the blue and orange soccer balls they have more mass than the black soccer ball changed speed by the same amount
Answer: d :The blue and orange soccer balls; they have more mass than the black soccer ball, but changed speed by the same amount.
Answer:
the answer is d
Explanation:
You are doing math homework and get frustrated and throw the 7 kg book with a force of 47
Newtons. How much acceleration will the book have when you throw it?
Answer:
The answer is 6.71 m/s²Explanation:
The acceleration of an object given it's mass and the force acting on it can be found by using the formula
[tex]a = \frac{f}{m} \\ [/tex]
f is the force
m is the mass
From the question we have
[tex]a = \frac{47}{7} \\ = 6.714285...[/tex]
We have the final answer as
6.71 m/s²Hope this helps you
What historical data from Tokyo could have helped in the development of tokyo's new flood protection system?
Answer: This historical data could have helped with the development of Tokyo’s new flood protection system:
historical frequency of flooding
amount of flooding during each storm
computer models forecasting the worst possible flooding
Explanation:
The frequency of flooding can help Tokyo measure when the next flood will be.
The amount of flooding can help Tokyo determine how much water will come during the flood.
And computer models forecasting the worst possible flood can help reach out to people and tell whether they need to evacuate or what they should plan for.
2. How can glass be a liquid if it's so hard?
Explanation:
Glass is not a liquid in the strictest sense of the word. But it is also not a standard solid. The chemistry of glass is complex and research is ongoing, but the current consensus is that glass is a phase of matter all its own, known as an "amorphous solid". Scientists refer to any amorphous solid as a "glass". Glass transitions are highly complex and cannot be treated in the same way as traditional phase transitions.
Answer:
It's a liquid state before its cooled.
help me solve. this is science. Which one is it
Answer:
d is the correct answer i think
Which of the following does not apply to water molecules?
Water molecules are polar
Water has cohesive properties
Water is less dense as a solid than a liquid
Water is not a very good solvent
Answer:
It is the last one.
Explanation:
Water molecules are polar, they have cohesive properties, and water is less dense when it is solid than when it is a liquid, that is why ice floats in liquid water. However, water is a very good solvent, it can dissolve many solids, including sugar, salt, and other hydrophilic substances.
I need help pretty bad can you answer all these questions
abiotic are non living things and biotic are living beings
Eukaryotic:these are developedand complete cells with well developed nucleus
PROKARYOTIC:these are primitive and incomplete cells without well developed nucleus difference between autotrophs and heterotrophs AUTOTROPHS :these are the organism which make their own food by photosynthesis
Heterotophs :these are the organism which depend on other organism for food
KINGDOMS:Monera
Protista
fungi
plantae
animalia
TAXONOMY IS the branch of biology that deals with the identification,nomenclature and classification of organismThe element with 5 electrons in its 3d sublevel is...?
Answer:
manganese, Mn
Explanation:
From the question, we have;
The number of electrons in the 3d sub level = 5
The kind of element = d-block element
On the periodic table, the elements with electrons in the 3d-sublevel in increasing order are;
Sc, 3d¹ 4s²
Ti 3d² 4s²
V 3d³ 4s²
Cr 3d⁵ 4s¹
Mn 3d⁵ 4s²
Fe 3d⁶ 4s²
Co 3d⁷ 4s²
Ni 3d⁸ 4s²
Cu 3d¹⁰ 4s¹
Zn 3d¹⁰ 4s²
The elements with 5 electrons in their 3d-sublevel are chromium Cr and manganese, Mn however the electronic configuration of chromium is given as 3d⁵ 4s¹ rather than 3d⁴ 4s² due to the minor difference in the gap of energy between the 3d and the 4s orbital as such the element that has the main characteristic of 5 electrons in its 3d sub level is manganese, Mn.
One isotope of oxygen differs from another isotope of oxygen in *
Each isotope of Oxygen has a different number of neutrons
Further explanationThe elements in nature have several types of isotopes
Atomic mass is the average atomic mass of all its isotopes
Isotopes are atoms has the same number of protons but has a different number of neutrons.
So Isotopes are elements that have the same Atomic Number (Proton)
Some of the isotopes of oxygen are:
[tex]\tt _8^{16}O,_8^{17}O,_8^{18}O[/tex]
Each isotope has 8 protons and 8 electrons but has a different number of neutrons
For O-16: number of neutrons = 16-8 = 8
For O-17: number of neutrons = 17-8 = 9
For O-18: number of neutrons = 18-8 = 10
Sodium hydrogen carbonate and citric acid
Word equation
Answer:
the right answer is:
Explanation:
How to Balance: NaHCO3 + HC2H3O2 = NaC2H3O2 + CO2 + H2O|
Answer:
NaHCO3 +C6H8O7
Explanation:
these are the formulas of sodium hydrogen carbonate and citric acid
Procedure: Step by step- what procedures should be followed while making the colors of the different fireworks (the shells and launch mechanisms will be made by the physics and design classes) the colors are: silver, white, gold and pink plz i need help
Answer:
It chemistry babe
Explanation:
If, in the reaction below, 49 grams of Fe3O4 produces a 78.25% yield of Fe. How many grams are produced?
Really need help on this please, I’ll give brainliest!!
4. Imagine you have a radioactive sample containing both Virtualium and decayed atoms of Virtualium. After analysis, you find it contains 10 atoms of Virtualium and 40 decayed atoms. How old is your sample? (Hint: You must use the half-life of Virtualium determined earlier in the activity.)
Answer:
25
Explanation:
at least three everyday things that exist or occur because of science.
Answer:
1.A POWER DRILL COULD SET YOUR HOUSE ON FIRE, IN THEORY.
2.STICKY NOTES COME OFF EASILY BECAUSE THEIR ADHESIVE IS UNEVEN. ...
3.GUM IS CHEWY BECAUSE IT'S MADE OF RUBBER. ...
4.OFFICE BUILDINGS ARE EVER-SO-SLIGHTLY TALLER AT NIGHT. ...
5.A LEGO BRICK CAN SUPPORT 770 POUNDS OF FORCE. ...
6.POLISHING SHOES IS LIKE FILLING IN A ROAD'S POTHOLES.
Explanation:
2 of 4
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10. The molar mass of CS2 is 76.14 g/mol. How many grams of CS2 are present in 10.00 mol?
Answer: C
Explanation:
There are 761.4 grams of CS2 in 10.00 mol.
To calculate the amount of grams present in a given amount of moles, the molar mass of the substance must be used, as follows:
[tex]m = MM \times mol[/tex]
In this way, just perform the following operation:
[tex]m = 76.14 \times 10[/tex]
[tex]m = 761.4 grams[/tex]
Thus, there are 761.4 grams of CS2 in 10 mol of the substance.
Learn more about mole calculation in: brainly.com/question/15693285
(Need Help ASAP) 23.5 grams of iron(III) oxide (Fe2O3) are reacted with excess carbon. What is the theoretical yield of iron metal?
2 Fe2O3 + 3 C --> 4 Fe + 3 CO2
The theoretical yield of iron metal : 16.418 g
Further explanationA reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.
Reaction
2 Fe₂O₃ + 3 C ⇒ 4 Fe + 3 CO₂
mol Fe₂O₃ (MW=159,69 g/mol) :
[tex]\tt \dfrac{23.5}{159.69}=0.147[/tex]
mol Fe₂O₃ : mol Fe = 2 : 4
mol Fe :
[tex]\tt \dfrac{4}{2}\times 0.147=0.294[/tex]
mass Fe(the theoretical yield) :
[tex]\tt 0.294\times 55.845~g/mol=16.418~g[/tex]
Answer:
The correct answer with signfigs is 16.4 for the first part
The second box is 88.4
Explanation:
Cream from milk can be separated by
process ......................................
Answer:
centrifugation
Explanation:
Someone tell me if I did the equation correctly or not.
Reaction between aqueous Washing soda and lemon juice=
3Na2Co3 + 2C6H8O7 = 2Na3(C6H3O7)+3CO2 (g) + 3H2O(l)
Sodium Carbonate commonly known as Sodium Carbonate is a inorganic compound which used in detergents and to soften the water. Its chemical formula is [tex]Na_{2}CO_{3_[/tex]. It is carbonate base
Lemon Juice:Lemon juice contain citric acid whose chemical formula is [tex]C_{6} H_{8} O_{7}[/tex]. Citric acid is a weak organic acid thus It is used for disinfectants and cleaning as well.
_____________________________________Reaction b/w Washing Soda and Citric AcidWhen Lemon Juice and Washing Soda react, the reaction is just an acid-base reaction and forms trisodium citrate and carbonic acid. The latter is then dissociated into Carbon Dioxide and Water. Carbon Dioxide escapes in the form of bubbles and Sodium Citrate(salt) and Water behind.
(citric acid)+ (sodium carbonate)= (trisodium citrate)+(water)+(carbon dioxide)
OR[tex]2C_{6}H_{8}O_{7} + 3Na_{2}CO_{3} ---> 2Na_{3}(C_{6} H_{3} O_{7})_{2} + 3H_{2}O + 3 CO_{2}[/tex]
_____________________________________Best Regards,'Borz'