Answer:
A gaping hole in the ozone layer over Antarctica was discovered in the mid 1980s. The international community agreed the Montreal Protocol in 1987, which banned most of the offending chemicals.
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Answer:it's either the first or second one
Explanation:
the layers of the earth
What do the three types of mixtures have in common?
(colloid, solution, suspension)
Answer:
A colloid is a heterogeneous mixture in which the dispersed particles are intermediate in size between those of a solution and a suspension. The particles are spread evenly throughout the dispersion medium, which can be a solid, liquid, or gas.
Explanation:
where are the oldest stars on the hr diagram????
Answer: The oldest stars are found on the top right on the HR diagram. Hope this helps!
The oldest stars on the Hertzsprung-Russell (HR) diagram are located in the lower-right region known as the main sequence turnoff, the stars in the universe can se seen and studied in several ways.
The main sequence turnoff represents the point where stars begin to leave the main sequence and enter different stages of evolution. The position of the turnoff depends on the age of the stellar population being observed. Older stellar populations, such as globular clusters or the halo stars of a galaxy, have turnoffs located at lower luminosities and cooler temperatures.
Learn more about the Hertzsprung-Russell (HR) diagram here
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Use the diagram below to answer the following questions.
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E TE
Figure B
In Figure B, which region contains the noble gas family of elements?
ОА
OD
ОС
OB
Noble gas located in the region D
Further explanationNoble gas are located in group 18 in the periodic table consisting of helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), have a stable electron configuration where the valence electrons are 8(full outer shell of electrons), so it is very hard to react because of its stability
If we look at the periodic system of the elements, the noble gases are on the far right, so that in Figure 8 it is located in area D
And the other region :
A : alkali elements(group 1),
B : alkaline earth elements(group 2)
C : halogen elements(group 17)
How many rings/energy levels would the Bohe model for an element
have if it had 12 electrons?
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how does the immune system uses feedback mechanisms?
Answer:The main job of the innate immune system is to fight harmful substances and germs that enter the body, for instance through the skin or digestive system. The adaptive (specific) immune system makes antibodies and uses them to specifically fight certain germs that the body has previously come into contact with.
Which element has the least density at STP?
Answer:
Helium, this noble gas has the least density at STP
Explanation:
Which answer choice correctly lists only elements?
A
Cl, Na, CH3, Ne
B
Mg, NO2, Mg, B
C
H2O, Li, N, I2
D
N2, O2, Al, Zn
Group of answer choices
A
Answer:
D
Explanation:
Nitrogen^2, Oxygen^2, Aluminum, Zinc
the others have combination
SOMEONE ANSWER?!!?!?!,!,EMERGENCY Can someone tell me the answer plz plz I’ll give you brainlist and points plz This is my final test No wrong answers
Answer: Should be A)
Explanation:
the size of planets effects the amount of gravitational force each planet has, like jupiter, it has the most gravity.
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Electron geometry of the central atom br in brf4+
Answer:
Octahedral
Explanation:
Recall that according to Valence Shell Electron Pair Repulsion Theory(VSEPR) the shape of a molecule is based on the number of electron pairs on the outermost shell of its central atom.
In BrF4^-, the bromine atom is surrounded by 6 electron pairs. Four bond pairs and two lone pairs. This means a total of six regions of electron density.
According to VSEPR Theory, BrF4^- has an octahedral electron geometry and its the molecular geometry will be square planar since it is of the type AX4E2.
An image of the BrF4^- is attached below.
What happens in this circuit if one of the light bulb burns out?
1. Both light bulbs will stop glowing
2. The other light bulb will stay on but get dimmer
3. the other light bulb will stay on and glow more brightly
4. the battery will lose its charge and stop working
Answer:
option 3
Explanation:
it is so because when both bulbs were there It took more electricity to charge both of them. now since only one is there it takes the power that is produced which made the other bulb glow and uses it for itself.
I'm sorry if u didn't understand
A science teacher asked students to calculate the density of a toy block. The mass of the block was 110 grams and the volume of the block was 8 cubic centimeters. What was the density of the toy block in cubic centimeters?
Answer:
13.75
Explanation:
Density is equal to mass divided by volume. 110/8 = 13.75
Write application of isotopes .
Answer:
In the chemical industry.
Isotopes are the atoms of the same element with same atomic no: and different mass numbers. ... ⇒As isotope of uranium is used as a fuel in nuclear reactor. ⇒An isotope of iodine is used in the treatment of goitre. ⇒An isotope of cobalt is used in the treatment of cancer.
(oh no)
What is the mass of silicon when there are 1.8 x 10^21 atoms of silicon?
Answer:
Mass = 0.084 g
Explanation:
Given data:
Mass of silicon = ?
Number of atoms of silicon = 1.8 × 10²¹ atom
Solution:
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
1.8 × 10²¹ atom × 1 mole / 6.022 × 10²³ atoms
0.299× 10⁻² mol
0.00299 mol
Mass of silicon:
Mass = number of moles × molar mass
Mass = 0.00299 mol × 28.1 g/mol
Mass = 0.084 g
1. Shankar and Sameer performed an experiment to differentiate primary, secondary and tertiary amines in a laboratory.Shankar correctly identified those 3 compounds but Sameer could only identify primary amine. a) What may be the reagent used by Sameer 1) Ammonical Silvernitrate solution 2) Chloroform & Caustic potash 3) Aqueous Copper Sulphate solution
Answer: 2) Chloroform & Caustic potash
Explanation:
The carbylamine reaction is a kind of chemical test which is done to detect primary amines in an unknown solution. It cannot detect secondary and tertiary amines.
The reaction involves the heating with up of the unknown solution with alcoholic potassium hydroxide or caustic potash and the chloroform.
In the presence of primary amine, the production of isocyanide results.
A force between an object and the surface it is moving over, is known as what?
power
O velocity
O force
O friction
Which process is caused by natural selection
Answer:
Four general conditions necessary for natural selection to occur are: More organisms are born than can survive. Organisms vary in their characteristics, even within a species. Variation is inherited.
Answer:
Natural selection can lead to speciation, where one species gives rise to a new and distinctly different species. It is one of the processes that drives evolution and helps to explain the diversity of life on Earth.
Explanation:
do all-stars mak energy through fusions
Where does the chemical energy of food start?
Answer:
Chemical energy in foodChemical energy in foodAs the bonds between the atoms in food loosen or break, a chemical reaction takes place, and new compounds are created. The energy produced from this reaction keeps us warm, helps us move, and allows us to grow. Different foods store different amounts of energyExplanation:
plz mark as brainilist
Answer:
BELOW !!
Explanation:
Chemical energy in food
As the bonds between the atoms in food loosen or break, a chemical reaction takes place, and new compounds are created. The energy produced from this reaction keeps us warm, helps us move, and allows us to grow. Different foods store different amounts of energy.
What are the flocculation basins?
Answer:
Flocculation is the operation in which the coagulated water must be gently mixed at a propeller speed of 15 to 20 rpm to promote the growth of the floc. ... The flocculation basin often has a number of compartments with decreasing mixing speeds as the water advances through the basin.
In diamond, each carbon atom is covalently bonded to four other carbons in a
a. Polyhedron
b. Hexagon
c. Pentagon
d. Tetrahedron
Answer:
Tetrahedron
Explanation:
Each carbon atom in a diamond is covalently bonded to four other carbons in a tetrahedron. These tetrahedrons together form a three-dimensional network of six-membered carbon rings in the chair conformation, allowing for zero bond-angle strain.
If the producers of the ecosystem below make 14,000 units of energy. How much energy would be available to the very top trophic level?
Answer:
1.4
Explanation took test
list three things that rely on the Sun as the major source of energy
Answer:
Three things that rely on the sun for energy is coal,oil, and natural gases
Explanation:
We use engery too cook our food that's an example of how gases are used.
We run our cars .Cars use oil.
And we use electricity for lights. You need coal for the electricity
Answer:
*Sun sends oxygen so all living kind (humans, plants, animals etc.) can live
*The sun sends heat to the earth so it wouldnt freeze
*We can use the sun as to create solar energy
Explanation: I hope this helps <3
“True or False”
Unsaturated solution contains the maximum amount of solute dissolved by a given amount of solvent
ANSWER- True
EPLANATION
what's the molar mass of Li3p
Answer:
51.79g Li₃P.
Explanation:
Li has a molar mass of 6.94 g (since there are 3, you multiply it 3 times) and P has a molar mass of 30.97 g. 6.94(3) + 30.97 = 51.79g.
Which one of the following is not an agent of chemical weathering?
proprionic acid
carbon dioxide
acid rain
Answer:
its proprionic acid which do not cause any hazardous effect on environment it only effect internal body of human if it is ingested.
Explanation:
What would happen if a proton, an electron, and 2 neutrons were removed from Lithium (7)
Answer:
This would give us Helium 4.
Explanation:
Lithium7 has 3 protons, 4 neutrons and 3 electrons.
Removing 1 Proton 1 electron and 2 neutrons would form an element with
2 protons 2 electrons and 2 neutrons.
This is Helium 4.
Which of the following best describes spectator ions? A. that do not participate in the reaction B. lons made when compounds dissolve in water C. that are made of a single element D. Ions that combine to form a precipitate
Answer: A. that do not participate in the reaction
Answer:
a
Explanation:
a p e x :)
Do sulphates react with acids
no it cannot I hope I helped
Answer:
Can not
Explanation:
Because both are salts of sodium and hydroxide