Answer:
1) The percentage of oxygen in dry air is _______
C. 21
2) The composition of the Earth’s earliest atmosphere was different to that of the present atmosphere. Which of these gases was present in large amounts in the Earth’s earliest atmosphere?
B. CARBON DIOXIDE
Hope it helps
have a nice day
Answer: The percentage of oxygen in dry air is . 21
Explanation: Ammonia gases was present in large amounts in the easth7s earliest atmosphere
Hope it will help you
(d) (i) How can the water molecules from the iceberg end up as water in the lake?
Explanation:
If the iceberg is near the lake and the water molecules melt, then the molecules will slide down. The iceberg could be melting for many reasons - it can be purposely destroyed, the sun could be melting it, or it might naturally fall in. So, this is the answer to your question. Hope it helps!
if drop a watermelon from the top of one of the tower dorms at CSU, and it takes 3.34 seconds to hit the ground, calculate how tall the building is in meters and then convert into feet.
Answer:
179.5 feet
Explanation:
54.718 m converted to 179.5 feet.
radical example ....
The structure shown is an example of what kind of molecule?
A) Ether
B) Alkene
C) Polymer
D) Monomer
Answer:
i think its C polymer hope it helps
 Help ASAP only right answers only no spam don’t answer if you don’t know
i know the answer is a theory
Which best describes a swimming pool?
A.
It is a solute.
• B.
It IS
solvent.
C.
It is solution.
D.
It is a reactant.
•
E.
It is a product.
Answer:
Swimming pool is an example of solution
Explanation:
It has water (solvent) and dissolve ion (solute)
Answer:
it is a solution
Explanation:
the combining of (water and Cl and other pool chemicals) make it a solution.
How many ATOMS of boron are present in 3.61 grams of boron trifluoride ?
Answer:
To determine the number of atoms of Boron that are present within 3.61 grams of Boron Trifluoride, it would be best to convert the grams to moles of the compound and then after that use the Avogadro's number to determine the number of molecules and then use the 1 to 3 ratio to determine the total number of Boron atoms.
WHAT IS PHOTOSYNTHESIS??
Answer:
the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product.
Answer:
the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product.
what is the application of chemistry
Answer:
Chemistry plays an important and useful role towards the development and growth of a number of industries. This includes industries like glass, cement, paper, textile, leather, dye etc. We also see huge applications of chemistry in industries like paints, pigments, petroleum, sugar, plastics, Pharmaceuticals.
Please a little help in this I will really appreciate it
Answer:
b is your answer...........
If a reaction occurs, what will be the products of the unbalanced reaction below?
Cu(s) + Ni(NO3)2(aq)
The Activity Series of Elements
A.
CuNi(NO3)4(s)
B.
Ni(s) + Cu(NO3)2(aq)
C.
No reaction will occur.
D.
CuNi(s) + NO2(g)
Cu(s) + Ni(NO3)2(aq) ⇒Ni(s) + Cu(NO3)2(aq)
The answer is option B.
What is electrochemical series?
Electrochemical or hobby series when the electrodes (metals and non-metals) in touch with their ions are organized on the idea of the values of their preferred discount potentials or standard oxidation potentials, the resulting series is called the electrochemical.
The electrochemical series is built up by means of arranging various redox equilibria so as of their fashionable electrode potentials (redox potentials). The maximum poor E° values are placed at the pinnacle of the electrochemical series, and the maximum wonderful at the lowest.
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every action produces an equal and opposite -- ---------- when one object exterts a force on another object,the second object pushes back with the same amount of---------
someone knows the answer
A gas is put into a cosed container.
The container and the gas inside it are heated.
What will happen to the pressure inside the container?
Answer:
When gases in containers are heated, their molecules increase in average speed. This means that they exert a greater force when they collide with the container walls, and also collide with the walls more frequently. The gas is therefore under greater pressure when its temperature is higher.
A 20.0 mL solution of NaOH is neutralized with 24.1 mL of 0.200 M HBr. What is the concentration of the original NaOH solution
Answer:
0.241 M
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
HBr + NaOH —> NaBr + H₂O
From the balanced equation above,
The mole ratio of acid, HBr (nₐ) = 1
The mole ratio of base, NaOH (n₆) = 1
Finally, we shall determine the concentration of the NaOH solution. This can be obtained as follow:
Volume of base, NaOH (V₆) = 20 mL
Volume of acid, HBr (Vₐ) = 24.1 mL
Concentration of acid, HBr (Cₐ) = 0.2 M
Concentration of base, NaOH (C₆) =?
CₐVₐ / C₆V₆ = nₐ/n₆
0.2 × 24.1 / C₆ × 20 = 1/1
4.82 / C₆ × 20 = 1
Cross multiply
C₆ × 20 = 4.82
Divide both side by 20
C₆ = 4.82 / 20
C₆ = 0.241 M
Therefore, the concentration of the NaOH solution is 0.241 M
How many bonds can a carbon atom form?
O A. 1
B. 2
C. 4
O D. 3
Which redox reaction would most likely occur if silver and zinc metal were added to a solution that contained silver and zinc ions?
Answer:
D. Zn²⁺ + 2Ag → Zn + 2Ag⁺
Explanation:
On the reduction potential chart, we have that silver ion Ag⁺ is a stronger oxidizing agent than, zinc, Zn, which is a reducing reducing agent the compared to silver
Therefore, the redox reaction that will occur is that the zinc, Zn, will be oxidized to Zn²⁺ ion, while the silver, Ag²⁺ ion will be reduced to silver deposits Ag, therefore, the zinc will displace the silver in the solution containing silver and zinc ions because zinc is higher than silver in the reactivity series
The reduction potential Zn → Zn²⁺ + 2e⁻ = +0.76
The reduction potential for Ag⁺ + e⁻ → Ag = +0.8
Therefore, given that redox reactions are reversible, we get the following likely redux reaction;
Zn(s) + 2Ag⁺(aq) ⇄ 2Ag(s) + Zn²⁺(aq)
Therefore, from the given options;
Zn²⁺(aq) + 2Ag(s) → Zn(s) + 2Ag⁺(aq) is the reaction most likely to occur.
How many grams of ammonia can be produced from reacting a 450 L sample of nitrogen gas at a temperature of 450 K and a pressure of 300 atm?
Answer: The mass of ammonia is 124457.96 g which can be produced from reacting a 450 L sample of nitrogen gas at a temperature of 450 K and a pressure of 300 atm.
Explanation:
Given: Volume = 450 L
Temperature = 450 K
Pressure = 300 atm
The reaction equation is as follows.
[tex]N_{2} + 3H_{2} \rightarrow 2NH_{3}[/tex]
Here, 1 mole of nitrogen reacts to give 2 moles of ammonia.
From the given data, moles of nitrogen are calculated as follows.
PV = nRT
where,
P = pressure
V = volume
n = no. of moles
R = gas constant = 0.0821 L atm/mol K
T = temperature
Substitute the values into the above formula as follows.
[tex]PV = nRT\\300 atm \times 450 L = n \times 0.0821 L atm/mol K \times 450 K\\n = \frac{300 atm \times 450 L}{0.0821 L atm/mol K \times 450 K}\\= \frac{135000}{36.945}\\= 3654.08 mol[/tex]
For 3654.08 moles of nitrogen, the moles of ammonia produced is as follows.
[tex]2 \times 3654.08 mol\\= 7308.16 mol[/tex]
Therefore, mass of ammonia (molar mass = 17.03 g/mol) is calculated as follows.
[tex]Moles = \frac{mass}{molarmass}\\7308.16 mol = \frac{mass}{17.03 g/mol}\\mass = 124457.96 g[/tex]
Thus, we can conclude that the mass of ammonia is 124457.96 g which can be produced from reacting a 450 L sample of nitrogen gas at a temperature of 450 K and a pressure of 300 atm.
True or false, Henry Moseley discovered through X-Ray crystallography the number of neutrons that were present
in the nucleus of atoms of every element.
Answer:
Im pretty sure its true
Explanation:
Answer:
answer is true .
Explanation:
this may help you
Select the structure that corresponds
to the name:
decanoic acid
COOH
A.
B. CH3(CH2)7COOH
C. both
Answer:
b
Explanation:
Molecular formula of Decanoic Acid is C₁₀H₂₀O₂ therefore Option A is the right answer.
What is Decanoic Acid ?Decanoic Acid is a C10 , straight chain , saturated fatty acid . Its general formula is C₁₀H₂₀O₂ .
In the first option we can see a straight chain , saturated fatty acid and the molecular formula is also same as decanoic acid .
In second option the molecular formula is C₉H₁₈O₂ which is not same as Decanoic Acid.
Hence option A is the right answer.
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please provide is matter about us pure all NCERT questions and answers
Answer:
I hope that's what u were lookong for :))
Explanation:
help sdfghrthfbfdve aahhhhhhhh
how many distinct monochlorinated products can result when methylcyclohexane is subjected to free radical chlorination under UV light
Answer:
How many distinct monochlorinated products can result when methylcyclohexane is subjected to free radical chlorination under UV light.
Explanation:
Consider 1-methylcyclohexane:
Its structure is shown below:
It has primary [tex]1^o[/tex], secondary [tex]2^o[/tex]and tertiary [tex]3^o[/tex] carbons as shown in the image.
So, the following mono chlorinated product will be formed.
Oxygen is a diatomic element.why give reason.
Answer:
Diatomic molecules contain two atoms that are chemically bonded. If the two atoms are identical, as in, for example, the oxygen molecule (O2), they compose a homonuclear diatomic molecule, while if the atoms are different, as in the carbon monoxide molecule (CO), they make up…
Explanation:
yei hoo arko aaxaina ...
Balance the equation of. _C + _O2 -- _CO
Explanation:
2C +O2 = 2CO
this will be the answer
The combination of ions most likely to produce a precipitate is Group of answer choices Mg2 and C2H3O2-. Fe3 and OH-. Li and PO43-. Pb2 and NO3-. NH4 and SO42-.
Answer:
The combination of ions most likely to produce a precipitate is a group of answer choices:
lead nitrate soluble in water
Mg2+ and C2H3O2-.
Fe3+ and OH-.
Li+ and PO43-.
Pb2+ and NO3-.
NH4+ and SO42-.
Explanation:
Among the given options,
magnesium acetate, lithium phosphate, lead nitrate, ammonium sulfate are soluble in water.
The only one which is insoluble in water is [tex]Fe^3+[/tex] and [tex]OH^-[/tex] combination.
[tex]Fe(OH)_3[/tex] is insoluble in water. It forms a precipitate.
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.
_______organisma consist of only one cell and _________ organisms consist of many cells
Answer:
Unicellular organisms consist of only one cell and multicellular organisms consist of many cell.
Explanation:
Living things made up of a cell are called unicellular beings. They are very small and simple. In other words, unicellular organisms are those that are formed only by a single cell in which all the vital functions necessary for life are produced. For this reason, they are mostly microscopic organisms. Examples of unicellular organisms are viruses or bacteria.
Multicellular organisms are made up of a large number of cells. They present, therefore, a greater complexity than unicellular organisms in terms of the functions they develop. All current multicellular organisms come from a single cell, that is, they begin their life being unicellular. That is, they are formed from a zygote. Some examples of multicellular organisms are mammals, fungi, and mosses.
So, unicellular organisms consist of only one cell and multicellular organisms consist of many cell.
Which statement is not true about the periodic table?
A. Elements in the same family have the same number of protons.
B. An element of the table is represented by a box with a symbol in it.
C. Elements in the same period of the periodic table have the same
number of electron shells.
D. It is organized by atomic number.
Elements in the same family have the same number of protons. This statement is not true about the periodic table. Therefore, option A is correct.
What is periodic table ?The chemical elements are arranged in rows and columns in the periodic table, sometimes referred to as the periodic table of the elements. It is frequently used in physics, chemistry, and other sciences and is frequently regarded as a symbol of chemistry.
The table can be used by scientists to anticipate chemical reactions, study trends in the periodic properties of certain elements, and speculate on the properties of yet-to-be-discovered elements. The elements are arranged in the contemporary periodic table according to their atomic numbers and periodic characteristics.
The periodic table has changed to represent more than 150 years of chemical and physics research and development.
Thus, option A is correct.
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Cotton plant is mainly harvested at flowering stage true false
All light waves can be described in terms of their speed, frequency, and_____
