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.
A 15.8 g sample contains 3.60 g F, 4.90 g H, and 7.30 g C. What is the percent composition of hydrogen in this sample?
Answer: 22.7848% F or 23%
Explanation: %F = 3.6g/15.8g • 100% = 22.7848% F
The percentage composition of hydrogen in the given sample is equal to 31%.
What is percentage composition?The percentage composition of a given compound can be described as the ratio of the quantity of each element to the total quantity of individual elements in the compound multiplied by 100. The quantity can be measured in terms of grams of the elements present in the sample.
The percent composition is expressed in its composition in terms of all the elements present. Thus, it helps in the chemical analysis of any given compound.
The percentage composition is expressed using the following formula,
Percentage composition of E = (E/T) × 100
Where E represents the total quantity of element E present in the compound and T represents the total quantity of all the elements present in the compound.
Given, the mass of the F, H, and C is 3.60g, 4,90 g, and 7.30 g respectively.
The total mass of the given sample = 15.8 g
The mass of the hydrogen in the sample = 4.90 g
The percent composition of H = (4.90/15.8) × 100 = 31 %
Therefore, the percent composition of hydrogen in this sample is 31%.
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Nitrogen dioxide gas is dark brown in color and remains in equilibrium with dinitrogen tetroxide gas, which is colorless.
2NO2(g) ⇌ N2O4(g)
When a light brown colored mixture of the two gases at equilibrium was moved from room temperature to a higher temperature, the mixture turned dark brown in color.
Which of the following conclusions about this equilibrium mixture is true?
This reaction is exothermic because the system shifted to the left on heating.
This reaction is exothermic because the system shifted to the right on heating.
This reaction is endothermic because the system shifted to the left on heating.
This reaction is endothermic because the system shifted to the right on heating.
Answer:
This reaction is exothermic because the system shifted to the left on heating.
Explanation:
2NO₂ (g) ⇌ N₂O₄(g)
Reactant => NO₂ (dark brown in color)
Product => N₂O₄ (colorless)
From the question given above, we were told that when the reaction at equilibrium was moved from room temperature to a higher temperature, the mixture turned dark brown in color.
This simply means that the reaction does not like heat. Hence the reaction is exothermic reaction.
Also, we can see that when the temperature was increased, the reaction turned dark brown in color indicating that the increase in the temperature favors the backward reaction (i.e the equilibrium shift to the left) as NO₂ which is the reactant is dark brown in color. This again indicates that the reaction is exothermic because an increase in the temperature of an exothermic reaction will shift the equilibrium position to the left.
Therefore, we can conclude that:
The reaction is exothermic because the system shifted to the left on heating.
The reaction is exothermic and the equilibrium position shifted to the left hand side.
An exothermic reaction is one in which heat is given out. Hence, the equilibrium position moves towards the left when the temperature is increased in an exothermic reaction.
Given the reaction, 2NO2(g) ⇌ N2O4(g) the appearance of a dark brown gas at high temperature implies that the reaction is exothermic and the equilibrium position shifted to the left hand side.
Learn more about exothermic reaction: https://brainly.com/question/15308590
A chemical bond formed when two atoms share two pairs of electrons is a ________ bond; it is best described as ________.
Answer:
A chemical bond formed when two atoms share two pairs of electrons is a double bond; it is best described as a covalent bond.
Explanation:
A chemical bond in which two pairs of electrons are shared has to be defined as covalent since ionic bonds don't involve electron sharing. They consist only of electrostatic attraction between ions.
Select from below all elements that follow the DUET rule (not the octet rule). (you can select multiple)
a) Li
b) Mg
c) O
d)He
e) H
f) Ne
The charge on a charged sphere is concentrated at (or on) its ________.
Central Core
Interior
Surface
I ANSWERED IT BUT SOMEONE SYAYS ITS COPY SO WHAT COULD I DO ;(
Answer:
The charge on a charged sphere is concentrated at (or on) its central core .hope it is helpful to you
why are metal containers not used for storing acids
Answer : Metal containers are not used for storing acid because most of the time acid reacts with almost every metal and produces salts or oxides which alters the acid characteristics making it useless .......
When a theory is disposed by further evidence, which of the following occurs
Answer:
it adds to scientific knowledge
Help ASAP only right answers only no spam don’t answer if you don’t know
Answer:
theory
Explanation:
if you assume something that you didn't see occuring it is called a theory
What is a precipitate?
1) A solid product of a chemical reaction that is in aqueous form.
2) A solid product of a chemical reaction that is not in aqueous form.
Freé point
[tex] \: \: \: \: \: \: [/tex]
Answer
Tq so much.
Pls follow me and Mark as brainliest Plsssssssss
Answer:
Thank you so much.
which among the following pairs are not isotopes?
Which is a constructive process? Rivers carrying sediment down stream, the rusting of a bridge, waves cutting back a beach front, volcanic eruption caused by plate tectonics
Answer:
volcanic eruption caused by plate tectonics.
Explanation:
Constructive process is one in which memories are influenced by some events. When a person tries to retrieve the memory he first click some event which is associated with that memory and then whole flash backs comes to his mind.
What is the wavelength of a wave that has a frequency of 6.1 x 109 Hz ? c = λυ where c = 2.998 x 108 m/s
a. 20.4 m
b. 2.04 m
c. 0.49 m
d. 0.049 m
Answer:
Wavelength = 0.049 m
Explanation:
Given that,
The frequency of a wave,[tex]f=6.1\times 10^9\ Hz[/tex]
We need to find the wavelength of the wave. We know that,
[tex]c=f\lambda\\\\\lambda=\dfrac{c}{f}\\\\\lambda=\dfrac{2.998 \times 10^8}{6.1\times 10^9}\\\\\lambda=0.049\ m[/tex]
So, the wavelength of the wave is 0.049 m.
Complete the following blanks on the basis of law of conservation of mass.
1) Na + O2 -----> 2NaO
8 g + 65 g ---> ______
2) 2H2 + O2 → 2H2O
24 g + ____ → 62 g
8g + 65g = 73g
24g + 38g = 62g
Answer:
1)Na + O2 = > 2NaO
8 g + 65 g = > 73g
2) 2H2 + O2 → 2H2O
24 g + 38g→ 62 g
Help asappppp quickly only right answers aloud
Answer:
Inference
Explanation:
A conclusion reached on the basis of evidence and reasoning is called an inference.
If 1000. mL of water freezes, which of the following is a reasonable approximation for the volume of the resulting ice?
Group of answer choices
1000. mL
961 mL
1040 mL
No answer text provided.
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Answer:
If 1000. mL of water freezes, which of the following is a reasonable approximation for the volume of the resulting ice?
Group of answer choices
1000. mL
961 mL
1040 mL
Explanation:
Ice is fewer denser than water.
The reason is the volume occupied by the same mass of ice with water is more than the volume occupied by water. Ice has more empty space within it.
Due to this reason, ice floats on water.
When 1000ml of water freezes to ice then its volume is greater than water.
Among the given options the correct answer is 1040 mL .
SI units is an improved version of MKS system.
Answer:
the S.I unit
Explanation:
is the best unite
a beam balance is called a first class lever why?
Answer:
A beam balance is an example of a first class lever.
Explanation:
A beam balance is an example of a first class lever. In a first class lever, the fulcrum is between the effort (force) and the load. The effort (force) moves over a large distance to move the load a smaller distance.
Other examples of first class lever are pliers, scissors, a crow bar, a claw hammer, a see-saw and a weighing balance etc.
which states of matter can flow from one place to another
Answer:
Liquid
Explanation:
Quite an easy question!
Answer:
Liquid
Explanation:
I was passing by lol
Which of the following make up an atom of gold? Select all that apply.
a
photons
b
electrons
c
neutrinos
d
protons
e
neutrons
Answer:
b, d, e
Explanation:
An atom is made up of electrons, protons and neutrons. Gold is an atom thus has the above particles.
A sample of substance "B" has a mass of 37.6g contained in a volume of
9.65mL. What is the density of substance "B"? (Report your answer with 3
s.f. E.G.: 6.00g/mL)
Answer:
3.90g/mL
Explanation:
To find the density of a substance, divide the mass by the volume.
So, 37.6 / 9.65 = 3.89637
then round to 3 significant figures
Good luck!
The southernmost point of india is _____
(a) indra point
( b) Gulf
( c) Amaravati
(d) jarawas
Answer:
(a) indra pointExplanation:
Indira point is the southern most point of India and is situated on great nicobar island in the nicobar island.
Answer:
Your Ans Is
(A) Indra point.
Help me please I need this quickly
9. melting point
10. balloons float because they are filled with hydrogen, a gas which is less dense than air.
11. specific gravity
12. element
13. mixture
14. sodium and chlorine
15. cutting of paper
16. condensation
17. 1 and 3
18. heat energy is released
In the experiment "Beer-Lambert’s Law and Spectrophotometry", you prepared a calibration plot similar to the one pictured below. What is the approximate concentration of a solution whose absorbance is 0.35?
Answer:
0.025M
Explanation:
As you must see in your graph, each concentration of the experiment has an absorbance. Following the Beer-Lambert's law that states "The absorbance of a solution is directely proportional to its concentration".
At 0.35 of absorbance, the plot has a concentration of:
0.025MHow many GRAMS of fluorine are present in 5.35×1022 molecules of boron trifluoride?
what is the [h+] if the ph of a solution is 11.13
pls help
Explanation:
[tex][{H}^{ + }] = {10}^{ - pH} [/tex]
[tex] = {10}^{ - 11.13} [/tex]
[tex] = {10}^{ (- 11 - 0.13)} [/tex]
[tex] = {10}^{ - 0.13} \times {10}^{ - 11} [/tex]
[tex] = 0.741 \times {10}^{ - 11} \frac{mol}{litre} [/tex]
HOPE IT HELPS YOUHydrogen fluoride, HF exist as liquid at room temperature. Explain this phenomenon based on the formation of hydrogen bonds.
Explanation:
The hydrogen fluoride molecule is highly polar, in the liquid and gaseous phases, HF prone to formation hydrogen bonds. ... These hydrogen bonds are strong, their energy is 41.5 kj/mol.Hydrogen fluoride can be a liquid or gas at room temperature; it has a boiling point of 19.5 ºC. It is corrosive, colourless and has a very strong odour.The gaseous compound formed when dry fluorine gas reacts with dry Hydrogen, gas is called hydrogen fluoride. Hydrogen fluoride gas on condensation forms liquid hydrogen fluoride which is also referred to as anhydrous hydrogen fluoride or anhydrous hydrofluoric acidhope it helps
stay safe healthy and happy..what is 10x412x3021x13123
calculate the gravitional force in between two object of mass 25kg and 20kg if distance between them is 5m?
Answer:
Explanation:The equation for this is F = -GmM/R^2 where the minus sign says the force is attractive m is 10 kg, M is 20 kg and R is 5 meters. If you crunch the numbers you get an answer of:
Choose the molecular compound among the substances listed below.
options:
XeCl4
NaF
MnCl2
CaO
Nothing listed can be classified as a molecular compound.
Answer: Among the listed substances [tex]XeCl_{4}[/tex] is the molecular compound.
Explanation:
A chemical compound formed by the chemical combination of two or more non-metals is called a molecular compound or covalent compound.
For example, Xe and Cl are non-metals. The compound formed by them is [tex]XeCl_{4}[/tex] which is a molecular compound.
A molecular compound is formed by sharing of atoms between the combining atoms.
Whereas NaF, [tex]MnCl_{2}[/tex] and CaO are all ionic compounds as they are formed by chemical combination of a metal and a non-metal.
Thus, we can conclude that among the listed substances [tex]XeCl_{4}[/tex] is the molecular compound.
