How do human population growth trends differ between developed nations and developing nations?
Answer:
Growing population
The worlds developing regions will see 1.2 billion people added, a 20.7% increase; while the population of developed countries will increase a mere 3.3% adding 41 million to the current 1.3 billion people.
A chemistry assignment has a student conduct a single replacement reaction by adding 7.5g of sodium metal to 20.0g of aluminum chloride. How much aluminum in moles would precipitate out as a result of the reaction
Answer: 0.109 mol
Explanation:
Balanced chemical equation:
3 Na(s) + AlCl3(aq) --> 3 NaCl(aq) + Al(s)
3 moles of sodium metal react with 1 mole of aluminum chloride to produce 3 moles of aluminum chloride and 1 mole of solid aluminum
Molar mass of Na = 22.99 g/mol
Mass(Na) = 7.5 g
Find number of moles of Na:
n = mass of Na/molar mass of Na
=(7.5 g)/(22.99 g/mol)
= 0.3262 mol
Molar mass of AlCl3,
MM = 1*MM(Al) + 3*MM(Cl)
= 1*26.98 + 3*35.45
= 133.33 g/mol
Mass(AlCl3) = 20.0 g
Find number of moles of AlCl3,
n = mass of AlCl3/molar mass of AlCl3
=(20 g)/(1.333*10^2 g/mol)
= 0.15 mol
Balanced chemical equation is:
3 Na + AlCl3 ---> Al + 3 NaCl
3 mol of Na reacts with 1 mol of AlCl3
for 0.3262 mol of Na, 0.1087 mol of AlCl3 is required
But we have 0.15 mol of AlCl3
So, Na is the limiting reagent and we will use it in our further calculations.
According to balanced equation:
mol of Al formed = (1/3) * moles of Na
= (1/3)*0.3262
= 0.1087 mol
Answer: 0.109 mol of aluminum will precipitate out as a result of the reaction
explain chemical equilibrium
Answer:
chemical equilibrium, condition in the course of a reversible chemical reaction in which no net change in the amounts of reactants and products occurs. A reversible chemical reaction is one in which the products, as soon as they formed, react to produce the original reactants.
Explanation:
chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system.
If 3.500 moles of water react completely according to the following equation, how much heat must be absorbed in kilojoules? 6CO2+6H2O→C6H12O6+6O2ΔH=2,803 kJ
The amount of heat absorbed in kilojoules when 3.5 moles of water react is 1635.08 KJ
Balanced equation6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ ΔH = 2803 KJ
From the balanced equation for above,
6 moles of water reacted to absorb 2803 KJ of heat
How to determine the heat absorbedFrom the balanced equation for above,
6 moles of water reacted to absorb 2803 KJ of heat
Therefore,
3.5 moles of water will react to absorb = (3.5 × 2803) / 6 = 1635.08 KJ of heat
Thus, 1635.08 KJ of heat were absorbed by the reaction.
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If 30 grams of KCl is dissolved at 10°C, how many additional grams would be needed to make the solution saturated at 60°C? * Captionless Image 45g 20g 15g 75g
If 30 grams of KCl is dissolved at 10°C, 14 g of KCl should be added to make a saturated solution at 60 °C.
What is a saturated solution?A saturated solution is a solution in which there is so much solute that if there was any more, it would not dissolve. Its concentration is the same as the solubility at that temperature.
Step 1. Calculate the mass of water.At 10 °C, the solubility is 31.2 g KCl/100 g H₂O.
30 g KCl × 100 g H₂O/31.2 g KCl = 96 g H₂O
Step 2. Calculate the mass of KCl required to prepare a saturated solution at 60 °C.At 60 °C, the solubility is 45.8 g KCl/100 g H₂O.
96 g H₂O × 45.8 g KCl/100 g H₂O = 44 g KCl
Step 3. Calculate the mass of KCl that must be added.44 g - 30 g = 14 g
If 30 grams of KCl is dissolved at 10°C, 14 g of KCl should be added to make a saturated solution at 60 °C.
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What happens when the temperature of a gas is increased?
O A. The boiling point will increase,
O B. The collisions between molecules will decrease,
O C. The volume will increase,
D. The pressure will decrease,
Which of the following microbial growth mediums would be used to sample for fungi bacterial growth in the sterile environment ? a) MacConkey agar b) Trypticase soy agar c) Tryptone glucose extract agar d) Bacteriological agar
The microbial growth medium that would be used to sample for Fungi bacterial growth in sterile environment is : ( B ) Trypticase soy agar
What is a growth medium ?A growth medium is a solid or liquid which is designed to support the growth of population such as microorganism through cell proliferation. A growth medium contains nutrients which support the growth of the microorganisms.
A growth medium which will support the growth of both fungi and bacteria growth is a Trypticase soy agar medium.
Hence we can conclude that The microbial growth medium that would be used to sample for Fungi bacterial growth in sterile environment is : Trypticase soy agar
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A solution consists of 35.00 g of CuSO4 dissolved in 250.0 mL of water. The molar mass of Cu is 63.55 g/mol the molar mass of S is 32.07 g/mol, and the molar mass of O is 16.00 g/mol. What is the molarity of the solution?
The molarity of a solution that contains 35.00 g of CuSO4 dissolved in 250.0 mL of water is 0.88M.
How to calculate molarity?The molarity of a solution can be calculated using the following formula:
Molarity = no of moles/volume
According to this question, a solution consists of 35.00 g of CuSO4 dissolved in 250.0 mL of water.
no.of moles of CuSO4 = 35g ÷ 159.6g/mol
no. of moles of CuSO4 = 0.22 moles
Therefore; molarity of CuSO4 solution is calculated as follows:
M = 0.22 ÷ 0.25
M = 0.88M
Therefore, the molarity of a solution that contains 35.00 g of CuSO4 dissolved in 250.0 mL of water is 0.88M.
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Calculate the pOH for a solution that has a hydroxide ion, (OH-) concentration of 5.02 X 10-4 M.
Calculate the pH.
Note: the answers should have three significant figures
Answer:
Explanation:
Calculate the pOH for a solution that has a hydroxide ion, (OH-) concentration of 5.02 X 10-4 M.
Calculate the pH.
Note: the answers should have three significant figures
______ contributes to the nitrogen cycle by removing nitrogen from the air and converting it into a form that is usable by plants.
plants
earthworms
fungi
bacteria
The complete statement is "Bacteria contribute to the nitrogen cycle by removing nitrogen from the air and converting it into a form that is usable by plants." This is further explained below.
What is Bacteria?Generally, Bacteria are mono-celled tiny creatures that can be beneficial. Bacteria are germs with a simpler cell structure than many other creatures.
In conclusion, Bacteria contribute to the nitrogen cycle by removing nitrogen from the air and converting it.
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Answer:bacteria
Explanation:
A solution consists of 35.00 g of CuSO4 dissolved in 250.0 mL of water. The molar mass of Cu is 63.55 g/mol the molar mass of S is 32.07 g/mol, and the molar mass of O is 16.00 g/mol. What is the molarity of the solution?
Answer:
0.87708moldm-3
Explanation:
[tex]molar \: mass \: of \: cuso4 = 63.55 + 32.07 + 4(16.00) \\ =159.62gmol {}^{ - 1} \\ mole(n) = \frac{mass}{molar \: mass } \\ n = \frac{35}{159.62} \\ n = 0.21927mol \\ molarity = \frac{n}{v} \\ molarity = \frac{0.21927}{0.25} \\ molarity = 0.87708moldm {}^{ - 3} [/tex]
Which bond links amino acids together?
glycosidic bond
hydrogen bond
phosphodiester bond
peptide bond
Answer:
Peptide Bonds
Explanation:
Peptide bonds are formed by a biochemical reaction that extracts a water molecule as it joins the amino group of one amino acid to the carboxyl group of a neighboring amino acid.
what are chemical reaction
Example:-
Burning of waxWe cannot pull back the reaction to get wax back .
Answer:
Explanation:
The permanent change in which a new substance is formed is called a chemical reaction.
For example:
i)Burning of wood
ii)Cooking rice
iii)Forming curd from milk
The burning of wood is a chemical reaction because it is a permanent change and it cannot be reversed. Once it is done, it is over it can't be done again. And in the case of example iii, the milk turns into curd by chemical reaction. A new substance i.e curd is formed from the milk.
Hope you understood!
buffer is prepared by adding 275 mL of .676M of HCl to 500 mL of .525M sodium acetate. What is the pH?
The pH of the buffer prepared by adding 275 mL of .676M of HCl to 500 mL of .525M sodium acetate is 6.45.
How to calculate pH?The pH of a buffer solution can be calculated by initially calculating the millimoles of both the conjugate base and acid.
Millimoles of hydrochloric acid = 275mL × 0.676M = 185.9millimolesMillimoles of sodium acetate = 500mL × 0.525M = 262.5millimolesFrom, Henderson Hasselbalch equation,
pH = pKa + log conjugate base/acid
pka of HCl = -6.3
-6.3 + log 262.5/185.9
6.3 + 0.15
pH = 6.45
Therefore, the pH of the buffer prepared by adding 275 mL of .676M of HCl to 500 mL of .525M sodium acetate is 6.45.
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How many R.P.'s is equivalent to 0.780 g of Na₂CO₂?
Answer:
pbo2+cl-=clo-+pb(oh)2
Explanation:
balance by ion electron
A reaction rate increases by a factor of 655 in the presence of a catalyst at 37°C. The activation energy of the original pathway is 106 kJ/mol. What is the activation energy of the new pathway, all other factors being equal? Group of answer choices 89.3 kJ/mol 16,600 kJ/mol 89.3 J/mol 16,600 J/mol
For a reaction rate that increases by a factor of 655 in the presence of a catalyst at 37°C, the activation energy of the new pathway is mathematically given as
Ea2=89.28JKoule/mol
What is the activation energy of the new pathway, all other factors being equal?Generally, the equation for the rate constant is mathematically given as
K=Ae^{Ea1/Rt}
Therefore
[tex]\frac{1}{655}=\frac{1}{8.31*3.10}(Ea2-105000)[/tex]
Ea2=89286.083Joule/mol
In conclusion, the activation energy
Ea2=89.28JKoule/mol
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How many grams does 5 helium atoms weigh?
Answer:
4.002602
Explanation:
the average that reflects the typical ratio of natural abundances of its isotopes.
The weight of 5 helium atoms in grams is 20.01301 grams.
What are atoms?Atoms are defined as the smallest unit into which matter can divided without the release of electrically charged particles.
It is also defined as a building block of matter and were discovered after big bang theory. It is a fundamental piece of matter.
The weight of 1 helium atom = 4.002602 g
So, the weight of 5 helium atom = 4.002602 x 5
= 20.01301 g
Thus, the weight of 5 helium atoms in grams is 20.01301 grams.
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Name the Covalent compound NH3O2
The name of the covalent compound NH3 O2 is dihydroxylamine.
Naming compoundsAccording to the task content;
It follows that the given covalent compound whose name is to be written is; NH3O2.On this note, the compound possesses 2 oxygen atoms, 3 Hydrogen atoms and 1 Nitrogen atom. Hence, the name of the covalent compound is Dihydroxylamine.
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If 0.380 mol of barium nitrate is allowed to react with an excess of phosphoric acid, how many moles of barium phosphate could be formed?
Ba (NO3)2+ H3PO4 → Ba3(PO4)2+ HNO3
If 0.380 mol of barium nitrate is allowed to react with an excess of phosphoric acid, 0.127 moles of barium phosphate could be formed.
How to calculate number of moles?The number of moles of a compound can be calculated stoichiometrically as follows:
Based on this question, the following chemical equation is given:
Ba (NO3)2+ H3PO4 → Ba3(PO4)2+ HNO3
The balanced equation is as follows:
3Ba(NO3)2 + 2H3PO4 → Ba3(PO4)2 + 6HNO3
3 moles of barium nitrate produces 1 mole of barium phosphate
Therefore, 0.380 moles of barium nitrate will produce 0.380/3 = 0.127moles of barium phosphate.
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write the formula for lead oxide.
Answer:
Lead(II) oxideExplanation:
Lead(II) oxide, also called lead monoxide, is the inorganic compound with the molecular formula PbO. PbO occurs in two polymorphs: litharge having a tetragonal crystal structure, and massicot having an orthorhombic crystal structure. Modern applications for PbO are mostly in lead-based industrial glass and industrial ceramics, including computer components. It is an amphoteric oxide.[3]IUPAC nameLead(II) oxideOther namesLead monoxideLithargeMassicotPlumbous oxideGalena PreparationPbO may be prepared by heating lead metal in air at approximately 600 °C (1,100 °F). At this temperature it is also the end product of oxidation of other oxides of lead in air:[4]Thermal decomposition of lead(II) nitrate or lead(II) carbonate also results in the formation of PbO:2 Pb(NO3)2 → 2 PbO + 4 NO2 + O2PbCO3 → PbO + CO2PbO is produced on a large scale as an intermediate product in refining raw lead ores into metallic lead. The usual lead ore is galena (lead(II) sulfide). At a temperature of around 1,000 °C (1,800 °F) the sulfide is converted to the oxide:[5]2 PbS + 3 O2 → 2 PbO + 2 SO2Metallic lead is obtained by reducing PbO with carbon monoxide at around 1,200 °C (2,200 °F):[6]PbO + CO → Pb + CO2pls brainlest meh
Which one of these are a physical property? Select all that apply. a. Luster (shininess) Conducts Electricity Reactivity with water d. Temperature b. 0 0
What is the volume of 0.960 moles of sulfur trioxide?
Answer:
76.86g
Explanation:
the molar mass of sulfur trioxide is about 80.06, so 80.06 grams per mol, 0.96*80.06=76.86g
Gives 2 reaction in which benzene ring is retained and 2 reaction in which benzene ring is not retained
Hey dear,
Benzene is a 6-C cyclic structure with alternate double bonds.
● Reactions -
1) Benzene to cyclohexane -
Benzene can be reduced to cyclohexane with
the help of Ni/H2. C6H6 + 3H2 --> C6H12
All 3 double bonds in ring are reduced here.
2) Benzene to benzoquinone - Benzene can be oxidized to benzoquinone with
the help of acidic K2Cr207. C6H6 +3[O] --> C6H4O2 + H2O
Only 1 double bond is lost in this reaction.
Hope this helps you.
According to Bohr's Model, which one is correct about a transition from n=2 to n=1 in a hydrogen atom?
When an electron moves from n = 2 to n = 1, it emits a photon of ultraviolet light.
What happen in transition from n= to n=1?During transition from n=2 to n=1 in a hydrogen atom, the electron emits energy in the form of photon. We know that when electron absorb energy, it moves from lower level to higher level and vice versa.
So we can conclude that when an electron moves from n = 2 to n = 1, it emits a photon of ultraviolet light.
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What is the most metallic character with low ionization energies
Answer:
Metals tend to lose electrons in chemical reactions, as indicated by their low ionization energies. Within a compound, metal atoms have relatively low attraction for electrons, as indicated by their low electronegativities.
Remove all the tape pieces from part A, and throw them in the trash. Next, follow these steps to compare pieces of sticky tape that have different charges:
Tear off two pieces of tape that are about 15 cm (6 inches) long. Similar to part A, fold under a half inch of each piece to make the strips easier to pull off.
Stick one of the pieces onto the tabletop. Smooth the tape down.
Stick the second piece of tape onto the tape piece you just placed. Do not cover the tab of the first piece of tape.
Grasp one tape tab in each hand. Carefully pull both pieces off the table and separate them. Turn the non-sticky sides of the tape toward each other.
What do you observe? If there’s an interaction, explain whether the tape pieces attract or repel each other. (ANSWER ASAP)
The interaction which will occur when the non sticky tape pieces are turned towards each other is attraction.
What is Attraction?This involves the coming together of objects as a result of a force. When non-sticky sides of the tape are brought towards each other attraction takes place due to the sticky content.
This however wears off after some time thereby making it the most appropriate choice.
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Explain how energy is conserved in combustion reactions.
Answer:
That’s because of the law of conservation of energy, which states that: Energy cannot be created or destroyed.
Explanation:
Energy may change form during a chemical reaction. For example, energy may change from chemical energy to heat energy when gas burns in a furnace. The exact amount of energy remains after the reaction as before.
Which statement describes a digital signal?
Answer:
digital signal
Answer:
Its made of numbers
Explanation:
did the assignment, hope this helps :]
what is the mass percentage of Li2CO3
Answer: its supposed to be 18.78%.
Explanation:
2. A body was discovered in the woods. The man has been missing for two days. The
average temperature the previous 48 hours was 50° fahrenheit. When the body was
discovered, it was at peak rigor.
The man has been missing for two days. The average temperature the previous 48 hours was 50° fahrenheit. 12-24 hours is the time. body was discovered.
Time is the ongoing progression of existence and things that happen in what seems to be an irrevocable order from the past, present, and forward into the future. It is a quantity that is a part of several measurements that are used to compare the length of events or the gaps between them.
To compare how long they last, to order events, and to measure how quickly things change in the real world or in our conscious experience. Along with the three spatial dimensions, time is frequently referred to as an a fourth dimension. A body was discovered in the woods. The man has been missing for two days. The average temperature the previous 48 hours was 50° fahrenheit. 12-24 hours, body was discovered.
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