Answer:
Water is one of the most precious resources the earth provides to mankind. Its use in modern age is manifold. We drink water to satisfy our thirst. We use it for domestic needs, irrigation, industrial use, transportation, power production and waste disposal. Water is universal solvent.
Thanks to our nature; it is very rich in water. About three-fourth of the earth's surface is covered with water. But only a small portion of total water resources is actually available for human use. Majority, about 97.3% is present in oceans and is salty in nature.
The fresh water constitutes only 2.7%. Out of this, inland" surface waters i.e. lakes, rivers, and ponds account for hardly 0.02%. This relatively negligible portion of the earth's water is crucially important to all form of terrestrial and freshwater aquatic life. We get water mainly from three sources;
1 Rain water.
2 Surface water
3 Ground water
Pedro adds 1.25 moles of helium to a balloon that already contained 4.51 moles of helium creating a balloon with a volume of 8.97 liters. What was the volume of the balloon before the addition of the extra gas
Answer:
don't know what u mean by that
Explanation:
so help me
list the symbols for the noble gases
Answer:here:
Explanation:helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og).
How many grams of nacl are present in 350 ml of a 0. 277 m solution of sodium chloride? a 1. 66 g b 16. 2 g c none of these d 97. 0 g e 5. 67 g
A NaCl solution of 350 mL volume and a concentration of 0.277 M will contain 5.67 grams of the salt.
Mole calculationRecall that:
Mole = molarity x volume.
Also:
Mass = mole x molar mass
Hence;
Mole of 350 mL, 0.277 NaCl = 0.350 x 0.277 = 0.097 moles
Mass of 0.097 moles NaCl = 0.097 x 58.44 = 5.67 grams
Thus, a 350 mL, 0.277 M NaCl solution will contain 5.67 grams of the salt.
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When a stone is dipped in a glass containing some water, the level of water rises but when a
spoon of sugar is added to it and stirred, the water level does not rise? why?
Explanation:
It's so because we know that stone is insoluble, ain't it, so it takes space in water & the water level rises.
But, when a spoon of sugar is added to water, it is soluble & hence mixes with water, so it doesn't rise.
I Hope this helps! (ㆁωㆁ)
The pressure inside of the chem-101 laboratory is 751 mm Hg. Calculate the pressure in units of atmospheres? (760 mm Hg = 1.00 atm)
751/760 x 1 atm = 0.988 atm
A chemist wants to extract copper metal from copper chloride solution. The chemist places 0.50 grams of aluminum foil in a solution containing 0.75 grams of copper (II) chloride. A single replacement reaction takes place. Which statement explains the maximum amount of copper that the chemist can extract using this reaction?
Unbalanced equation: CuCl2 + Al → AlCl3 + Cu
A. Approximately 0.36 grams, because copper (II) chloride acts as a limiting reactant
B. Approximately 1.8 grams, because copper (II) chloride acts as a limiting reactant
C. Approximately 0.36 grams, because aluminum acts as a limiting reactant
D. Approximately 1.8 grams, because aluminum acts as a limiting reactant
Approximately 0.36 grams of Cu are produced because copper (II) chloride acts as a limiting reactant.
What is an Equation ?A representation of a chemical reaction using symbols of the elements to indicate the amount of substance, usually in moles, of each reactant and product.
Based on the balanced equation of reaction and the reacting masses, approximately 0.36 grams of Cu are produced because copper (II) chloride acts as a limiting reactant.
The amount of copper produced is determined from the balanced equation of the reaction.
The equation of the reaction is given below:
3 CuCl₂ + 2 Al → 2 AlCl₃ + 3 Cu
molar mass of CuCl₂ = 132 g/mol
molar mass of Al = 27.0 g
molar mass of Cu = 64.0 g
moles of aluminium in 0.50 g = 0.50 / 27 = 0.018 moles
moles of CuCl₂ in 0.75 g = 0.75/132 = 0.00568 moles
Therefore, CuCl₂ is the limiting reactant
3 moles of CuCl₂ produces 3 moles of Cu
0.00568 moles of CuCl₂ will produce 0.00568 moles of Cu
Mass of 0.005 moles of Cu = 0.00568 * 64 = 0.36 g of Cu
Therefore, approximately 0.36 grams of Cu are produced because copper (II) chloride acts as a limiting reactant.
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Based on your observations, do you think any of the samples are the same substance?
Yes
Yes
No
No
Explain your answer below.
How many moles of hydrogen are required to react with 2 moles of oxygen?
Answer:
4 moles of H2
Explanation:
From the equation, twice as many
2 moles of O2 requires 4 moles of H2
1mol of Oxygen requires 2 moles of Hydrogen
Moles of oxygen=2Moles of Hydrogen
2(2)4molesDuring photosynthesis and cellular respiration plus carry out processes that involve both light and energy and chemical energy. Sort each tile into the correct column.
-Used to directly power cell growth
-Used to directly power photosynthesis
-Released through cellular respiration
-Captured by chloroplyll
Chemical energy power cell growth, solar radiation power photosynthesis and is captured by chlorophyll, and carbon dioxide is released through cellular respiration.
Photosynthesis and RespirationDuring photosynthesis, solar radiation is captured by chlorophyll in green plants, and this is used to fix inorganic carbon dioxide and water to produce plant food in the form of carbohydrates.
During respiration, the carbohydrates synthesized via photosynthesis are broken down chemically to extract the energy locked in them. Carbon dioxide is produced as a by-product.
The energy extracted by respiration is used to power metabolic processes in plants.
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What else is produced during the replacement reaction of silver nitrate and potassium sulfate? 2agno3 k2so4 ag2so4 ________ kno3 2kno3 k2 2agno3
When silver nitrate reacts with potassium sulfate, the products would be silver sulfate and potassium nitrate.
Products from reactionsThe reaction between silver nitrate and potassium sulfate is a double replacement reaction that is represented by the following equation:
[tex]2 AgNO_3 + K_2SO_4 --- > Ag_2SO_4 + 2 KNO_3[/tex]
Thus, the products are silver sulfate ([tex]Ag_2SO_4[/tex]) and potassium nitrate ([tex]KNO_3[/tex]).
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Answer:
A
Explanation:
when a 16.9 g sample of NaOH dissolves in 70.0 g of water in a calorimeter, the temperature rises from 22.4°C to 86.6°C. calculate ΔH for the process
NaOH(s) → Na(aq) + OH(aq) ΔH = ?
ΔH for the process is -252.3 cal/mol or -1056 j/mol.
What is Enthalpy of Solution ?A solid salt compound dissociates in liquid water to form an aqueous solution of its constituent ions.
This is a chemical reaction, with the required heat change at constant pressure termed the enthalpy of solution.
If this value is positive, then the final prepared solution will have a lower temperature than the starting pure solvent.
Conversely, a negative enthalpy value results in a solution temperature that is higher than the starting solvent temperature.
It is given that
NaOH (s) → Na (aq) + OH (aq)
mass of NaOH is 16.9 g
mass of water = 70 g
ΔT = 86.6-22.4 °C = 64.2 °C
q = m × Cg × ΔT
q = amount of energy released or absorbed
m = mass
Cg = specific heat capacity
ΔT = change in temperature
n = m ÷ M
n = moles of solute
m = mass of solute
M = molar mass of solute
ΔHsoln = q ÷ n
ΔHsoln = molar enthalpy (heat) of solution
q = amount of energy (heat) released or absorbed
n = moles of solute
Cg= 1 cal/gm/°C
Now substituting the values in the equation
q = m × Cg × ΔT
q = 16.9 * 1 * 64.2
q = 1085 cal
n = m ÷ M
M= 70/18=3.9
n=16.9/3.9
n=4.3
ΔH = q ÷ n
ΔH =1085 /4.3
ΔH= -252.3 cal/mol or -1056 j/mol
Therefore ΔH for the process
NaOH(s) → Na(aq) + OH(aq)
is -252.3 cal/mol or -1056 j/mol
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Which answer choice best explains why atoms of carbon-14 (c-14) are unstable? atoms of c-14 have too many negatively charged electrons and too few positively charged protons. atoms of c-14 have too many positively charged protons and too few negatively charged electrons. there are 2 more protons than neutrons in the nucleus. there are 2 more neutrons than protons in the nucleus.
The best choice that explains why atoms of carbon-14 (c-14) are unstable is there are 2 more protons than neutrons in the nucleus
What is a stable atom?An atom is said to be stable if the number of neutrons in the nucleus is greater than number of protons in the nucleus, because the the neutrons increases the nuclear force which keeps the atom stable.
Thus, the best choice that explains why atoms of carbon-14 (c-14) are unstable is there are 2 more protons than neutrons in the nucleus.
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Answer:
D. there are 2 more neutrons than protons in the nucleus.
Explanation:
How many moles is 3.48 g of carbon?
[tex]\text{No. of moles } = \dfrac{\text{Mass of substance(C)} }{\text{Molar mass of substance(C)}}\\\\\\~~~~~~~~~~~~~~~~~~~=\dfrac{3.48}{12}~ \text{mol}\\\\\\~~~~~~~~~~~~~~~~~~~=0.29~ \text{mol}[/tex]
1
How many atoms of carbon would be present in a molecule of CCl4?
A
5
B
1
С
2
D 4
Answer:
There are 5! goodluck,
Explanation:
Some greenhouse gases, such as fluorocarbons (CFCs, HFCs, PFCs, etc.), are human-made. Others, such as water, methane, and carbon dioxide, are naturally produced. Which type of greenhouse gas (human-made or natural) is more difficult to control and eliminate? Which types are easier? In three to five sentences, provide evidence for your argument.(4 points)
The natural types of greenhouse gases are more difficult to control and eliminate while the human-made type are easier.
What are greenhouse gases?Greenhouse gases are specific type of gases that have the ability to trap and release heat in their bonds.
Greenhouse gases are the cause of global warming, which is the gradual increase in temperature of the Earth's atmosphere.
However, greenhouse gases can either occur naturally or be synthesized artificially. The naturally-occuring greenhouse gases like CO2 are more difficult to control because they are not produced by humans.
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Which model states that an acid is a substance that contains hydrogen and ionizes to produce hydrogen ions?.
Answer:
The Arrhenius model
Explanation:
The Arrhenius state that an acid is a substance that contains hydrogen and ionizes to produce hydrogen ions in aqueous solution.
The following flow of energy takes place in one ecosystem: alga → insect → larva flatworm → fish.
Which trophic level has the most energy to pass on to the next?
A) insect larva
B) fish
C) flatworm
D) alga
Answer: D. Alga
Explanation:
!! How much has CO2 in the atmosphere increased since the Industrial Revolution? In the 10,000 years before the Industrial Revolution in 1751, carbon dioxide levels rose less than 1 percent. Since then, they've risen by
Answer:
Im pretty sure its B) 43
Explanation:
How many molecules are in 368 g of potassium hydroxide (KOH)?
Answer: 6.559055381954511
Explanation:
1. How many formula units are contained in 270.2 g of zinc nitrate, Zn(NO3)2?
50 POINTS
Zinc nitrate has 1 molecule of zinc (Zn), 2 molecules of nitrogen (N) and 6 molecules of oxygen (O).
Calculate the molecular mass of zinc nitrate by adding the molecular weights for all molecules in the compound.
Here are the molecular weights for each element:
Zn=65.38 g/mol
N=14.01 g/mol
O=16.00 g/mol
The molecular weight of zinc nitrate is then: 1*(65.38)+2*(14.01)+6*(16.00)=189.40 g/mol.
Using a conversion formula to calculate moles of zinc nitrate:
163.97gZn(NO
3
)
2
∗
189.40gZn(NO
3
)
2
1molZn(NO
3
)
2
=0.866molZn(NO
3
)
2
There are 0.866 moles of zinc nitrate.
Note: These numbers may vary slightly due to the source of the molecular weight data and the number of decimal places used.
How many moles of hydrogen gas would be required to produce 25 moles of H2O?
Answer:
There would be 25 moles
Explanation:
This is the equation for water (synthesis):
2H₂ + O₂ → 2H₂O
Since there are 25 moles of water, the moles of hydrogen gas will have 25 moles.
How many atoms of oxygen are in 2. 50 moles of so2?
The number of atoms of oxygen are present in 2.50 moles of sulfur dioxide is 30.110 × 10²³.
What is Avogadro's number?Avogadro's number is define as the number of atoms present in one mole of any substance and it is equal to 6.022 × 10²³.
In the 1 mole of SO₂ 2 moles of oxygen are present. So that in 2 moles of SO₂, 2(2.5) = 5 moles of oxygen is present.
No. of atoms of oxygen in 5 moles of oxygen will be calculated as:
No. of atoms = 5 mole × 6.022 × 10²³atoms per mole = 30.110 × 10²³atoms
Hence number of atoms of oxygen is 30.110 × 10²³.
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A mixture of helium, nitrogen and oxygen has a total pressure of 821 mmHg. The partial pressure of helium is 105 mmHg, and the partial pressure of nitrogen is 312 mmHg. What is the partial pressure (in mmHg) of oxygen in the mixture?
Answer:
Total partial pressure, Pt = 821 mm Hg
Partial pressure of Helium, P1 = 105 mm Hg
Partial pressure of Nitrogen, P2 = 312 mm Hg
Partial pressure of Oxygen, P3 = ? mm Hg
According to Dalton's law of Partial pressures,
Pt = P1 + P2 + P3
So, P3 = 404 mm Hg
how many moles of sodium sulfate will be formed if you start with 2.00 moles of sodium
Answer:
The molecular weight of sodium sulfate is 142.1 g/mol. To calculate the mass of sodium sulfate, substitute the values in the formula. Therefore, the mass of sodium sulfate formed when we start with 200.0 grams of sodium hydroxide and you have excess sulphuric acid is 355.25g.
What is created by the fusion of three helium nuclei?
- nitrogen
- iron
- oxygen
- carbon
- hydrogen
Answer:
carbon nuclei...........
What occurs as energy is transferred through the radiative zone of the sun? check all that apply. gamma rays are produced. photons are absorbed and reemitted. energy is transferred through the large-scale movement of material. photons are scattered in many directions. energy is released into the photosphere.
Answers:
1) Photons are absorbed by hot gas atoms.
2) Energy is transferred through large-scale movement of material.
3) Energy is released into the photosphere.
The Sun interior is divided into three regions: the inner core, the radiative zone and the convection zone.
The inner core is the central region of the Sun and all solar energy is produced in the core by nuclear fusion.
Radiative zone is around the inner core and in this area energy is transported by radiation.
The convection zone is the outer-most layer of the interior and in this area energy is transported by convection.
The isotope tritium has a half-life of 12. 3 y. Assume we have 11 kg of the substance. How much tritium will be left after 51 y? answer in units of kg
Half-life is a time in which the concentration of the substance gets reduced to 50% of the initial concentration. The number of tritium that will be left after 51 years is 0.624 kg.
What is an isotope?Isotopes are chemical substances that have the same atomic number but different atomic mass because they have a different number of neutrons in the nuclei.
The half-life of the isotope, tritium is 12.3 years. Assuming we have 11 kg of substance and a number of years 51 years.
[tex]11 \times 2 ^{\frac{-51}{12.3}} = 0.6239 \;\rm kg[/tex]
Therefore, the number of tritium that will be left after 51 years is 0.624 kg.
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How many total atoms are in one molecule of cobalt hydroxide?
Answer: Hello! I'm Jungkook. Here is your answer.....
1 Atom.
Explanation:
Hope this helps! Anneyong/Bye!
xoxoKookie
What is the ph of a solution that is 0. 50 m in hcooh (aq)? pka = 3. 75 for hcooh (aq)?
The pH of a solution that is 0.50 M in HCOOH is 2.045.
How do we calculate the pH?pH of the solution will be calculated by taking the negative logarithm of the concentration of H⁺ ion.
Given chemical reaction will be:
HCOOH(aq) ⇄ H⁺(aq) + HCOO⁻(aq)
Initial: 0.50 0 0
Equilibrium: 0.50-x x x
Given that, pKa = 3.75
Ka = [tex]10^{-pKa}[/tex]
Ka = [tex]10^{-3.75}[/tex] = 0.000178
Ka for the above equation will be written as:
Ka = [H⁺][HCOO⁻]/[HCOOH]
Ka = (x)² / (0.50-x)
x is negligible as compared to 0.5, so the equation becomes
0.000178 = (x)² / 0.50
x² = (0.000178)(0.5) = 0.000089
x = 0.009
[H⁺] = 0.009M
pH will be calculated as:
pH = -log(0.009) = -(-2.045) = 2.045
Hence pH of the solution is 2.045.
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Please help!!!
what is the name of pb(no3)2? explain how you determined the bond type and the steps you used to determine the naming convention for the compound.
The cation part is named first in an ionic compound and the anionic part is named with the suffix of ate, id etc. The name of the ionic compound Pb (NO₃)₂ is lead nitrate.
What are ionic compounds?Ionic compounds are formed between metals and nonmetals. Metals are electron rich and can easily lose electrons to form positively charged ions called cations.
Non-metals with electron-deficiency will gain electron from the metals and acquires a negative charge to form anions. The electrostatic force of this negative clouds and positive cloud from the cation is called ionic bonding.
For ionic compounds, the cation or metals are named first. Pb is a metal with two valence electrons and NO₃ group has a negative charge. Thus, Pb donates its two electrons each to each nitrate groups and the anionic part nitrate is named last.
Therefore, the compound name is lead nitrate.
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