A magnesium ribbon is cleaned to remove the protective layer of basic magnesium carbonate from its surface, so that it may readily combine with the oxygen in air (on heating).
Answer:
Magnesium gets covered with a layer of magnesium oxide when kept in air for a long time. This layer hinders the burning of magnesium. Hence, it is to be cleaned before burning.
PLEASE HELP
Which of the following correctly orders the types of radiation from the LONGEST wavelength to the SHORTEST wavelength?
A. Green Visible Light, Red Visible Light, Blue Visible Light, Ultraviolet
B. Microwave, Orange Visible Light, Ultraviolet, Violet Visible Light
C. Red Visible Light, Infrared, Microwaves, Radio waves
D. Microwave, Blue Visible Light, Ultraviolet, Gamma
Answer:
D. Microwave, Blue Visible Light, Ultraviolet, Gamma
Explanation:
colors longest to shortest are
red green blue violet
longest wavelength to shortest:
radio waves, microwaves, infrared, optical, ultraviolet, X-rays, and gamma-rays.
HELP ASAP Choose three sections of the electromagnetic spectrum. Rank them in order of energy. Give an example of how they are used for each.
Metals like potassium and sodium are kept in paroffin oil. Why?
Answer:
because they are high reactive to the air thats why we keep them in paroffin oil
The carbonyl carbon in a ketone is attacked primarily by the peroxy oxygen bonded to hydrogen as opposed to the peroxy oxygen bonded to carbon because:
Answer:
This is because peroxy oxygen bonded to hydrogen can easily undergo nucleophilic protonation with the carbonyl carbon to form an alcohol
Explanation:
A ketone is a functional group that contains a carbonyl group (carbon-oxygen double bond ( R1R2-C=O).
The carbonyl carbon doubly bonded to the oxygen is electron deficient as a result of difference in electronegativity between carbon and oxygen, hence is susceptible to nucleophilic attacks
R1R2 - C = O
where R1 and R2 are organic substituents.
The peroxy oxygen that is bonded to hydrogen (H -O-O-R) is the electron-rich centre and easily attacks electron-deficient centres like the carbonyl carbon in ketones to form an alcohol.
The bond between the hydrogen attached to the peroxy oxygen is broken and the resultant hydrogen ion undergoes protonation with the oxygen of the carbonyl group to form an alcohol
R1R2 - C = O + H - O-O - R =>
R1R2- CH - OH + R - O-O-R1
5.34x10 to the 27th power molecules of sulfur hexafluoride to moles of sulfur hexafluoride
Answer:
8.87 × 10³ moles.
Explanation:
To convert number of molecules of sulfur hexafluoride (SF6) to moles (n), we divide by Avogadro's number (6.02 × 10²³)
That is; n = N ÷ nA
According to the question, 5.34 x 10^27 molecules of SF6 was given in this question. Hence, the number of moles it contains is given as:
n = 5.34 x 10^27 ÷ 6.02 × 10²³
n = 5.34/6.02 × 10^ (27-23)
n = 0.887 × 10⁴
n = 8.87 × 10³ moles.
I’ll mark you as brainlister
please help. need this asap!!
Answer:
E.....Na2I.,.
Explanation:
Cuz sodium has a Vallency..1......lodide has Vallency 2
Diego is trying to lift a piano to the second floor of his house. Diego uses a pulley system and gives a big lift to the piano.The piano moves upward, then stops, and then it starts to fall to the ground. (The direction of the force of gravity is negative.) Which list best describes the forces on the piano in the proper order
Answer:
positive force → balanced force → negative force
Explanation:
np
Answer:
positive force → balanced force → negative force
Explanation:
:)))
Why is the charge on a charged sphere distributed uniformly over its surface?
-Similar charges seek to be the minimum distance possible from each other.
-Opposite charges seek to be the maximum distance possible from each other.
-Similar charges seek to be the maximum distance possible from each other.
-None of the above
Answer:
Similar charges seek to be the maximum distance possible from each other
Explanation:
On a charged sphere, there are like charges and these like charges are repelled by each other to the far ends of the sphere. Hence they are distributed uniformly in the sphere.
what is the formula of silver sulphate
Answer:
Ag2SO4
Explanation:
How many moles of carbon are in the sample?
Answer:
12.01 grams per mole
Explanation:
theres no sample or example so if theres grams of Carbon, convert it to moles using 12.01g/mol
The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction _____.
The most common carrier of communicable diseases are
a.cockroach
b.housefly
c.mosquito
d.spider
housefly
Explanation:
Because it one of the affective vector of disease carrier and it always roam towards wastes and dirty materials likely to get attracted . And it carries contagious disease from hospitals , infected patients , etc .
In an electrically neutral atom, the number of
protons equals the number of neutrons.
protons equals the number of electrons.
neutrons equals the number of electrons.
A. Protons equals the number of neutrons
B. Protons equal the number of electrons
C. Neutrons equals the number of electrons
Answer: B
Answer:
B
Explanation:
because protons have a +1 charge and electrons have a -1 charge, so if an atom is neutral it must have the same amount of protons and neutrons
different oil refineries in UAE
Answer:
Petroleum refinery capacity in the UAE 2009-2018
In 2018, the total production capacities of all refineries in the UAE were 1.13 metric barrels per day. Total total production capacity of the al-Ruwais refinery in the United Arab Emirates was approximately 817,000 metric barrels per day.
if sneezing is the response to smelling food is it conditioned or unconditioned
Answer:
i think its unconditioned response.hope it helpsstay safe healthy and happy.The bottle slides down the hill and is moving at a velocity of 14 meters/second the instant it hits the ground. The vertical height from where Jeff dropped the bottle is meters. Ignore friction, and use , PE = m × g × h, and g = 9.8 m/s2.
Answer:
10 m
Explanation:
From the question given above, the following data were obtained:
Velocity (v) = 14 m/s
Acceleration due to gravity (g) = 9.8 m/s²
Height (h) =?
Next, we shall determine the energy. This can be obtained as follow:
Velocity (v) = 14 m/s
Kinetic Energy (KE) =?
KE = ½mv²
KE = ½ × m × 14²
KE = ½ × m × 196
KE = m × 98
Finally, we shall determine the height. This can be obtained as follow:
Kinetic energy (KE) = m × 98
Acceleration due to gravity (g) = 9.8 m/s²
Height (h) =?
Since the object is falling from a particular height,
Potential energy (PE) = kinetic energy (KE)
PE = mgh
KE = m × 98
m × 9.8 × h = m × 98
Divide both side by m × 9.8
h = m × 98 / m × 9.8
h = 10 m
Thus, the bottle was dropped from a height of 10 m
convert 300g into kg
Answer:
0.3kg
Explanation:
in heating a kettle of water on an electric stove, 3.34×10^3 J of thermal energy was provided by the element of the stove. yet, the water in the kettle gained only 5.95×10^2 J of thermal energy. determine the percent efficiency of the electrical element in heating the kettle of water
Answer:
The percentage efficiency of the electrical element is approximately 82.186%
Explanation:
The given parameters are;
The thermal energy provided by the stove element, [tex]H_{supplied}[/tex] = 3.34 × 10³ J
The amount thermal energy gained by the kettle, [tex]H_{absorbed}[/tex] = 5.95 × 10² J
The percentage efficiency of the electrical element in heating the kettle of water, η%, is given as follows;
[tex]\eta \% = \dfrac{H_{supplied} - H_{absorbed} }{H_{supplied}} \times 100[/tex]
Therefore, we get;
[tex]\eta \% = \dfrac{3.34 \times 10^3 - 5.95 \times 10^2}{3.34 \times 10^3} \times 100 = \dfrac{549}{668} \times 100 \approx 82.186 \%[/tex]
The percentage efficiency of the electrical element, η% ≈ 82.186%.
describe the formation of ionic bonds in potassium chloride compound (5 marks)
Answer:
When the two atoms are in contact, potassium readily transfers its outer electron to chlorine which readily accepts it, resulting in both atoms achieving a state of eight outermost electrons. With this electron transfer, the ionic bond in KCl is formed.
Someone please do a True or false of all of these
Answer:
1. False
2. True
3. False
4. False
5. True
6. False
7. True
8. True
9. True
As Danny was pouring cereal for his breakfast, he noticed that the cereal box says that the cereal contains 5 milligrams of iron per serving. Danny decided to perform an experiment to test this claim. He found that the cereal contains 4.6 milligrams of iron per serving. Based on Danny's measurement, the value reported on the label is because .
The question is incomplete, the complete question is;
As Danny was pouring cereal for his breakfast, he noticed that the cereal box says that the cereal contains 5 milligrams of iron per serving. Danny decided to perform an experiment to test this claim. He found that the cereal contains 4.6 milligrams of iron per serving. Based on Danny's measurement, the value reported on the label is ( CORRECT OR INCCORECT) because A: (IT IS DIFFERENT FROM THE VALUE DANNY MEASURED) B: (IT IS REORTED TO THE NEAREST MILLIGRAM) C: (IT USES THE SAME UNITS THAT DANNY USED).
Answer:
CORRECT because IT IS REORTED TO THE NEAREST MILLIGRAM
Explanation:
In mathematics, values may be rounded up or down as required. In the case of this measurement of cereals by Danny, it is customary to measure the amount of iron per serving to the nearest milligram.
As such, even though Danny found out that the actual amount of iron per serving in the cereal is 4.6 milligrams, the value reported on the cereal box is still correct because it was reported to the nearest milligram hence the value had to be rounded up.
How does the alcohol enter the body? Describe the process. Where does most of the absorption take place?
Explanation: Once swallowed, a drink enters the stomach and small intestine, where small blood vessels carry it to the bloodstream. Approximately 20% of alcohol is absorbed through the stomach and most of the remaining 80% is absorbed through the small intestine.
Calculate the average atomic mass for element X.
(Please HELP)
Methane is approximately 23 times more powerful than carbon dioxide as a greenhouse gas. Which are significant sources of methane emissions
Answer:
anthropogenic sources like landfills, agricultural activities,coal mining and combustion and some sources are natural ones
Which of the following elements has three valence electrons? (2 points)
Li
C
Al
Mg
Answer:
Al
Explanation:
It has 3.
1. Which of the following species exhibit tetrahedral geometry?
a. CCl4 b. PCI5 c. NH3 d. CO2
2. Which statement correctly describes the Valence Shell Electron Pair Repulsion (VSEPR) Theory? The valence electron pairs are__________.
a. The valence electron pairs are given by the group number in the periodic table.
b. The valence electron pairs are the outermost electrons of the atom that areinvolved in the bonding.
c. The valence electron pairs repel one another and tend to stay as far apart aspossible.
d. The valence electron pairs are the lone pairs of the atom.
3. Which of the following statements about resonance is TRUE?
I. Resonance hybrids occur because a compound changes back and forth between two or more resonancestructures
II. Resonance structures differ in the arrangement of electrons but not in the arrangement of atoms.
III. Resonance hybrids contain delocalized electrons.
IV. Resonance structures for a given compound always contribute equally to the resonance hybrid.
V. Resonance structures occur when there are two or more valid Lewis structures for a given compound.
VI. Resonance hybrids are a composite of resonance structures.
a.I, II, V, VI
b. II, III, IV, VI
c. II, III, V, VI
d. II, IV, V, VI
4. How many resonance forms will nitrate ion (NO3) have?
a. - 1 b. 1 c. 2 d. 3
5. What is the first noble gas?
a. Xenon b. Radon c. Helium d. Krypton
6. What is the principle used for filling of atomic orbitals?
a. Azimithual Principle
b. Hund's Principle
c. Pauling's Exclusion Principle
d. Aufbau Principle
7. How many electrons can "m" shell accommodate?
a. 16 b. 17 c. 18 d. 19
8. What number of shells used for the accommodation of electrons in an atom? a. one b. two c. three d. four
9. What distribution does the electron configuration describe?
a. protons
b. neutrons
c. electrons
d. ions
10. How many total electrons can the "p" orbitals hold?
a. 3 b. 1 c. 7 d. 6
11. Who are the founding fathers of Quantum Mechanics?
a. Werner Karl Heisenberg
b. Isaac Newton
c. Erwin Schrodinger
d. a and c
12. There are _types of quantum numbers.
a. 2 b. 4 c. 5 d. 7
13. Which of the following elements can only form one bond in a Lewis structure? a. H b. O c. Al d. N
14. Which rule states that electron will go into empty orbitals of the same energy before entering into an orbital with an electron present?
a. Hand's rule
b. Hund's rule
c. Pauli Exclusion Principle
d. Aufbau Principle
15. What is the definition of diamagnetic atom?
a. An atom where all of the electrons are paired
b. An atom where some of the electrons are paired.
c. An atom where none of the electrons are paired.
d. An atom attracted to a magnetic field.
Answer:
a
Explanation:
Its because ammonium has thee hydrogen atoms
Na3N decomposes to form sodium and nitrogen gas at STP. If 13.7 L of nitrogen is produced
how many moles of Na3N was used? (22.4 L = 1 mole of any gas)
2Na3N --> 6Na + N2
Answer: 1.224 moles of [tex]Na_3N[/tex] were used.
Explanation:
We are given:
Volume of nitrogen gas produced = 13.7 L
At STP conditions:
22.4 L of volume is occupied by 1 mole of a gas
Applying unitary method:
13.7 L of nitrogen gas will be occupied by = [tex]\frac{1mol}{22.4L}\times 13.7L=0.612mol[/tex]
For the given chemical reaction:
[tex]2Na_3N\rightarrow 6Na+N_2[/tex]
By Stoichiometry of the reaction:
1 mole of nitrogen gas is produced by 2 mole of [tex]Na_3N[/tex]
So, 0.612 moles of nitrogen gas will be produced from = [tex]\frac{2}{1}\times 0.612=1.224mol[/tex] of [tex]Na_3N[/tex]
Hence, 1.224 moles of [tex]Na_3N[/tex] were used.
How many molecular of H2O and O2 are present in 8.5g of H2O2 ?
2H2O+O2--->2H2O2
8.5 gm H2O2=0.25 mole
hence H2O is also 0.25 mole i.e.4.5 gm
O2is 0.125 mole i.e.4 gm
Find the mass in grams of 15.00 moles of AICI:
Answer:
937.5g
Explanation:
No of moles = mass ÷ molar mass
According to this question, there are 15moles of the compound; AlCl
Molar mass of AlCl = 27 + 35.5
= 62.5g/mol
Using n = m/M.M
15 = m/62.5
m = 15 × 62.5
m = 937.5g
