Answer:
• Oxygen is an element
Answer:
We can call it an element.
What two things do astronomers need to know about a star in order to calculate its luminosity or absolute magnitude? A.color and size B.color and distance C.distance and brightness D.size and distance
(đ) is answer of question.
Explanation:
However, the brightness of a star depends on its composition and how far it is from the planet. Astronomers define star brightness in terms of apparent magnitude — how bright the star appears from Earth — and absolute magnitude — how bright the star appears at a standard distance of 32.6 light-years, or 10 parsecs.
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Astronomers measures the luminosity of stars by determining the magnitude of brightness and distance from earth.Thus option C is correct.
What is luminosity?Luminosity of a star is the total amount of energy radiated by them to a distance. The luminosity vary from star to star based on the distance to them.
Luminosity is basically measured in terms of brightness as observed from the earth. Stars will make a group in certain shapes and certain number called constellation. The overall brightness can be then higher for each constellation.
Astronomers define the brightness of stars by the apparent distance from the earth whereas the absolute magnitude is defined is terms of standard distance of 32.6 light years. Hence, the option C based on distance and brightness is correct.
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Using the periodic table, explain which pair of the following gases have the most similar properties and why. Nitrogen (N), Fluorine (F), Neon (Ne), Krypton (Kr), and Oxygen (O).
5. A football field is about 100 meters long. If it takes a person 20 seconds to run its length, how fast (what speed) were they running?
Answer:
Speed, v = 5 m/s
Explanation:
The length of the football field, l = 100 m
the person takes 20 seconds to run its length
v=
t
d
v=
20 s
100 m
v=5 m/s
When you rub an inflated balloonon your head on a dry day,it can make your hair stand up! what force is that?
When you rub an inflated balloon on your head and it makes your hair stand up, the force that makes the hair stand up is known as static electricity.
When the balloon is rubbed on the head, electrons from the hair atoms move into the balloon, thus making the balloon to be negatively charged and the hair positively charged due to loss of electrons.
Unlike charges attracts. Thus, when you try to pull the balloon away slowly, the positively charged hair and the negatively charged balloon will attract each other and this is usually what makes the hair stand up.
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Answer:
static electricity
Explanation:
this is because there is an imbalance between negative and positive charges
when you keep on rubbing, a negative charge is created which is carried by electrons.
when you pull the balloon away slowly, the opposite charges attract to each other which makes your hair attract to the balloon
what is the trend for atomic radii across the periods and down the group?
Answer:
So, in general, atomic radius decreases across a period and increases down a group. Across a period, effective nuclear charge increases as electron shielding remains constant.
Explanation:
Moving from left to right across a period, the atomic radius decreases. The nucleus of the atom gains protons moving from left to right, increasing the positive charge of the nucleus and increasing the attractive force of the nucleus upon the electrons.
Have a happy day! <3Miss Hawaii
what additional reaction product would result if naoh was used as a base in this reaction instead of k2co3?
Answer:
What reaction product would result if NaOH was used as a base in this reaction instead of K2CO3? If sodium hydroxide was used as the base of the reaction, then the reaction product formed would be an ethyl alcohol because it would undergo a hydrolysis reaction with addition of iodoethane
The entire carbonation reaction demonstrates how potassium carbonate (K2CO3) combines with water and carbon dioxide to create potassium bicarbonate (KHCO3) when exposed to combustion flue gases at low temperatures (40 to 80 °C) (Reaction 1)
What takes place when K2CO3 and water interact?In an extremely violent and exothermic reaction, potassium carbonate splits into potassium and carbonate ions when it interacts with water. When the ions interact, potassium oxide and carbonic acid are created.
K2CO3 come from : Potassium carbonate is a common ingredient in the manufacture of soap and glass. Additionally, it serves as a light drying agent. This substance is used as a buffering agent in numerous wine making procedures. Another usage for potassium carbonate is as a fire extinguisher.
K2CO3 created : Commercially, potassium carbonate is made by reacting potassium hydroxide with carbon dioxide:
2 KOH + CO2 = K2CO3 + H2.
K2CO332H2O sesquihydrate crystallizes from the solution ("potash hydrate").
The anhydrous salt is produced by heating this solid at 200 °C (392 °F).
It disintegrates into K2O+CO2 around 1200 C. (allreaction)
By converting carbonate into carbon dioxide and water, potassium carbonate can act as a base by forming potassium hydroxide.
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Someone pls help me I will make you you brain
Answer:It’s cyclone movement
Explanation:
which of the following atoms is most likely to bond with another atom?
Answer:
c. chlorine, with an outer electron shell filled with 7 of a possible 8 electrons
Explanation:
Hope this helps!
The structure in the option A has 7 electrons in the outer shell of its electronic configuration , is unstable and so is most likely to form bond with another atom.
What is electronic configuration ?Electrons are arranged in various shells around the nucleus , this arrangement is called electronic structure or configuration.
Each shell can occupy certain fixed number of electrons.
Beside Option A , all the other configurations show stable structures as the last shell has eight electrons and are stable according to the octet rule.
The structure in the option A has 7 electrons in the shell and so is most likely to form bond with another atom.
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How much effort force would you use to lift a 300 kg weight with a fixed pulley system?
Answer:
It would take 150 kg to lift the load
Explanation:
a bronsted lowry acid is defined as a substance that
Answer:
that donate H+ ion.
Explanation:
hope this helps :)
If a chemical reaction occurs in a flask, and the flask becomes colder, the reaction was exothermic. true or false
Answer:
false
Explanation:
hope this helps you
Answer:
False, if the flask becomes colder it's endothermic. I hope this helps! :)
Con que otras materias se relaciona la química
Answer:
Fisica, Astronomia, Biologia
Explanation:
con esta relacion entre ellas se puede explicar y comprender fénomenos de la naturaleza.
Give the number of the sample bottle that contains a substance that would be used in
each situation.
1.
Plumbing
5.
Computer chips
2.
Flavoring Food
6.
Edible Cooking Ingredient
3.
Crafts
7.
Edible Cooking Ingredient
For a headache
8.
Edible Cooking Ingredient
to o N O
4.
A horse runs 1 km in 15 s. What is the average speed
The average speed of the horse for the entire motion is 66.67 m/s.
The given parameters;
distance traveled by the horse, d = 1 km = 1,000 mtime of motion of the horse, t = 15 sThe average speed of the horse is calculated by dividing the total distance traveled by the horse by the time of motion.
The average speed of the horse is calculated as follows;
[tex]average\ speed = \frac{distance}{time} \\\\average\ speed = \frac{1000 \ m}{15 \ s} = 66.67 \ m/s[/tex]
Thus, the average speed of the horse for the entire motion is 66.67 m/s.
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What is the SI base unit of temperature?
Answer:
Kelvin
Explanation:
Help me out with this question , can someone give me the answer ?
:((
Answer:
I pretty usre they cause erosion wich makes fresh soil so B.
Explanation:
what is the amount of heat required to completely melt a 200
Someone pls help me I will make you brain
Answer:
a
Explanation:
i took test
Which element in the list is the most reactive?
C
Ba
S
Cs
Answer:
Cs
Explanation:
This element is the farthest right, and lowest meaning that the reactivity of it is very high.
1. valence electrons and electronegativity
2. Both reactivity and electronegativity decrease down a group.
3. Electronegativity decreases down a group, and reactivity increases down a group.
4. The number of valence electrons increases from left to right.
5. Cs
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How many cc of methane at not is required to react completely with 20cc of oxygen? Please helps meee!
Answer:22.4 L methane reacts with 44.8 L of oxygen to give 22.4 L of CO
2 and 44.8 L of water.
Explanation:
Someone pls help me I will make you brain
Answer:
A catalytic converter
Explanation:
Diesel filters are used to clean fuel not emissions, engine injection puts fuel directly into the engine and a transmission clutch changes the cars transmission.
Answer:
carbon monoxide and nitrogen oxide are needed to be properly maintained
isotopes Mg-24,Mg-25 and Mg-26 has natural abundance of 79.0%,10.0% and 11.0%. Calculate the relative atomic mass for isotopes Mg-24,Mg-25 and Mg-26.
Please help me with with this question....
when is it appropriate to form double or triple bonds in a lewis structure?
It is appropriate to form double or triple bonds in a Lewis structure when four or six electrons are shared.
A Lewis structure is a representation of a molecule using dots to show the valence electrons in the molecule. This dots are shown around the symbols of the elements.
However, in instances where four or six electrons are shared between bonding atoms, a double or triple bond is used. A double bond means that four electrons are shared. A triple bond means that six electrons are shared.
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Số amin bậc một có cùng công thức phân tử C3H9N là
A. 3. B. 1. C. 2. D. 4
Answer:
A.3
Three primary amines
Ba amin chính
Physics have been taking the Hippocratic Oath for more than 2,000 years. Among other things, to Serie doctors who take the oath promise to uphold doctor-patient confidentiality. Why do you think this is an ethical issue?
Answer:
Physicians and it is ethical because they promise to help
Explanation:
What is the wavelength of a radio wave that has a frequency of 9.40 X 10^8Hz?
3.1
Which of the following molecules contains only single bonds?
(A)CH3CH2COOH
(B) CH3COCH3
(C) HCN
(D)C2H6
(E) CO2
Answer:
D) C2H6
Explanation:
All the other molecules contain double (or triple) bonds except for C2H6.
which alkyl halide reacts fastest with trimethylamine in sn2 reaction?
Structure V reacts fastest with trimethylamine in SN2 reaction. Owing to less steric crowding in the transition state and ease of cleavage of the R - I bond
The question is incomplete, the complete question is shown in the image attache to this answer.
SN2 reaction is a type of nucleophilic reaction in which the nucleophile attacks the substrate from the reverse side. This is a synchronous reaction because the leaving group departs as the entering group attacks simultaneously in a hypervalent transition state.
SN2 reaction is favored by structure V owing to less steric crowding in the transition state and the easy of cleavage of the R - I bond. Hence, structure V reacts fastest with trimethylamine in SN2 reaction.
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3. What is the energy of a photon that has a frequency of 2.3 x 1014 Hz?
The energy of a photon that has a frequency of 2.3 x 10¹⁴ Hz is 1.524 × 10-¹⁹J
HOW TO CALCULATE ENERGY OF A PHOTON:
The energy of a photon can be calculated by using the formula as follows:E = hf
Where;
E = energy of photon (J)
h = Planck's constant (6.626 × 10-³⁴J)
f = frequency of photon (Hz)
According to this question, a photon has a frequency of frequency of 2.3 x 10¹⁴ Hz. The energy of the photon can be calculated as follows:E = 6.626 × 10-³⁴ × 2.3 × 10¹⁴
E = 15.24 × 10-³⁴+¹⁴
E = 15.24 × 10-²⁰J
E = 1.524 × 10-¹⁹J
Therefore, energy of a photon that has a frequency of 2.3 x 10¹⁴ Hz is 1.524 × 10-¹⁹JLearn more at: https://brainly.com/question/23180082?referrer=searchResults
Cho 200 g dung dịch NaCl 0,5M tác dụng hết với 400 ml AgNO3. Sau phản ứng thu được kết tủa và dung dịch không màu
a, Viết phương trình hóa học xảy ra?
b, Tính khối lương kết tủa tạo thành
c, Tính nồng độ mol của dung dịch AgNO3 đã tham gia phản ứng.
Answer:
Explanation:
a. NaCl+ AgNO3-----> NaNO3+ AgCl
b. Số mol của NaCl= 0,2*0,5= 0,1 (mol)
------> Số mol của kết tủa AgCl tạo thành= 0,1 mol (dựa vào phương trình hóa học)
-----> Khối lượng của kết tủa AgCl tạo thành= 0,1*143,5=14,35(g)
c. Số mol của AgNO3= số mol của NaCl= 0,1 (mol)
------> Nồng độ mol của dd AgNO3 đã tham gia phản ứng= [tex]\frac{0,1}{0,4}[/tex]=0,25(M)