Answer:
2 significant figures i.e. 2 and 7.
Explanation:
We need to find the number of significant figures in the given number i.e. [tex]2.7\cdot10^{-3}[/tex].
It has 2 significant figures i.e. 2 and 7.
It means the power of 10 doesn't count in the significant figures.
Hence, there are 2 significant figures.
When coal is burned to produce electricity, the electrical energy produced is less than the
potential energy in the coal. Which best explains this observation?
A. As coal is heated, some of the molecules move so fast that they are destroyed.
B. Some of the energy in coal is destroyed by the intense heat required to release its potential
energy
C. Some of the potential energy in coal is converted into forms of energy other than electricity.
D. The amount of potential energy in fuels is overestimated.
Answer: it should be c or b
Explanation:
The statement that best explains this observation is that some of the energy in coal is destroyed by the intense heat required to release its potential energy. The correct option is B.
What is electricity?Electricity is light energy that is produced when charged atoms move through a closed wire made up of a substance. The motion of the charged particle produces electricity.
Here, when coal is burned to produce electricity it is less than potential energy because in making energy some amount of energy is lost in the form of heat and is released. The amount of electrical energy generated from burning coal is less than the coal's potential energy.
Thus, the correct option is B. Some energy in coal is destroyed by the intense heat required to release its potential energy.
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CHEM help
i know how to report random answers btw
Answer:
ionic, they would make an ion
Explanation:
A scientists who studies how water moves around is called......
Answer:
A scientists who studies how water moves around is called "Hydrologist".
Which of following is true of liquids?
Group of answer choices
The particles move at a high rate of speed
The particles have a medium amount of kinetic energy and slide past one another.
The particles vibrate in place.
The particles have a fixed volume and shape
Answer:
The particles have a medium amount of kinetic energy and slide past one another
Explanation:
If particles move at a high rate of speed its gas, and if they vibrate in place and they have a fixed volume and shape its probably a solid. So a medium amount of kinetic enery is correct.
How many Na atoms are shown in the products?
Answer: 6.02214179×1023 atoms
Explanation: I think so
Explain the difference between a normal salt and an acid salt.
Answer:
The difference between normal salt and acid salt is that acid salt is basically made up of strong acid and also including a weak base. However normal salt is practically made up of strong base or even a weak acid and also a weak base. Acid salt or in a more logical term known as acidic salt ionises into a type of form of H + ions which is more than OH- ions, which is in a water solution. But even than normal salt ionises into a form of eqaul number of H+ ions and OH- ions in this so called water solution.
A friend tells you that's after a candle burn there is less matter than before the flame was lit is your friend correct explain why or why not
Answer:
See explanation
Explanation:
The law of conservation of matter states that "matter cannot be created or destroyed. In a physical change, substances can change form, but the total mass remains the same."(Virginia)
Hence, the quantity of matter present before and after the candle burn must remain the same in accordance with this law stated above.
Hence, my friend was not correct.
How many liters would 18.0 grams of water vapor occupy at 273 K and 1.00 atm?
Answer:
22.41 Liters
Explanation:
Using the general law equation;
PV= nRT
Where;
P = pressure (atm)
V = volume (L)
n = number of moles (mol)
R = gas law constant (0.0821 Latm/molK)
T = temperature (K)
According to the information provided in this question,
mass of water vapor = 18g
Molar mass of water (H2O) = 1(2) + 16 = 18g.
mole = mass/molar mass
- mole (n) = 18/18 = 1mol
V = ?
T = 273K
p = 1 atm
Using PV = nRT
V = nRT/P
V = 1 × 0.0821 × 273/1
V = 22.41 Liters
Thread-like structures that are found in the nucleus of a cell that contains all DNA.
A.) DNA
B.) Genes
C.) Chromosomes
D.) Nucleus
6. Besides hydrogen and the polyatomic ion ammonium, what type of element forms cations: metal, metalloid, non-metal?
Answer: Metals
Explanation:
When an atom accepts an electron negative charge is created on atom and is called as anion.
When atom loses an electron positive charge is created on atom and is called as cation.
The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Thus metals form cations.
Methanol, CH3OH, is the simplest of the alcohols. It is synthesized by the reaction of hydrogen and carbon monoxide. Write chemical reactions. If 500 mol of CO and 750 mol of H2 are present, which is the limiting reactant?
Answer:
The limiting reactant is H₂
Explanation:
The reaction of hydrogen (H₂) and carbon monoxide (CO) to produce methanol (CH₃OH) is the following:
2H₂(g) + CO(g) → CH₃OH(g)
From the balanced chemical equation, we can see that 1 mol of CO reacts wIth 2 moles of H₂. So, the stoichiometric ratio is:
2 mol H₂/1 mol CO = 2.0
We have 500 mol of CO and 750 mol of H₂, so we calculate the ratio to establish a comparison:
750 mol H₂/500 mol CO = 1.5
Since 2.0 > 1.5, we have fewer moles of H₂ than are needed to completely react with 500 moles of CO. In fact, we need 1000 moles of H₂ and we have 750 moles. So, the limiting reactant is H₂.
If the temperature of a chemical reaction was reduced, how could the reaction rate most likely be increased?
Group of answer choices
decrease the pressure acting on the system
add a chemical inhibitor
decrease the surface area of the reactants
increase the concentration of the reactants
Answer:
Increase the concentration of the reactants.
Explanation:
This question seems vague, but to put it simply, the reaction rate decreases with a decrease in temperature, so we need to find a way to increase the reaction rate again. When you lower temperature, the molecules are slower and collide less. So therefore, in other words, we need to find a way to increase the rate of collisions between molecules. When the temperature drops, if we increase the concentration of the reactants, we are able to increase the rate of collisions between molecules. As a result, reaction rate is increased once again.
If the temperature of a chemical change was reduced,the reaction rate could most likely be increased by increasing the concentration of the reactants.
What is a chemical change?Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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2 C2H6 + 7 026 H2O + 4 CO2
If 5.25 moles of ethane (C2H6) and 15.0 moles of oxygen are reacted,
which is the limiting reactant?
Answer:
Oxygen is limiting reactant
Explanation:
Based on the chemical reaction:
2C2H6 + 7O2 → 6H2O + 4CO2
2 mole of ethane reacts with 7 moles of oxygen
For a complete reaction of 5.25 moles of ethane are required:
5.25 moles Ethane * (7mol Oxygen / 2mol Ethane) = 18.38 moles of oxygen
As there are just 15.0 moles of oxygen
Oxygen is limiting reactanti’m not even sure if this is the right subject or like if this is even a question lol anyways
List at least 3 physical or chemical properties of the element Cobalt
Which statement compares you tractive forces that hold particles together
Answer:
The answer is Ionic and covalent binding produces compounds, while hydrogen bonding and Van der Waals forces join separate molecules together.
Consider the following equilibrium reaction having gaseous reactants and products.
4HCl + O2 ⇌ 2H2O + Cl2
Which of the following would result from increasing the concentration of H2O?(4 points)
A. The rate of the backward reaction increases.
B. The concentration of hydrochloric acid decreases.
C. The rate of forward reaction increases.
D. The concentration of chlorine increases.
Answer:
A. The rate of the backward reaction increases.
Explanation:
The stress caused by increasing the H2O concentration would shift the system to the left, producing more reactants to counter the stress of added H2O. This means the rate of the backward reaction would increase.
Answer:
A
Explanation:
just took the test
The valency of silver in silver sulphide (Ag₂S).
Answer:
Explanation:a
What is the oxidation number of nitrogen in pb (NO3)2
Answer:
The oxidation number of N in is +5
Explanation:
3. Why are amino acids important in living organisms?
Answer:
Explanation:
Their role is to compose proteins. Amino acids have many biologically important functions. They are also energy metabolites,many of them are essential nutrients. Amino acids can function as chemical messengers in communication between cells.
Answer:
well Aside from their role in composing proteins, amino acids have many biologically important functions. They are also energy metabolites, and many of them are essential nutrients. Amino acids can often function as chemical messengers in communication between cells.
Explanation:
this should be the answer
marking brainliest please help
Large sharks eat many other marine life animals. The sharks and the animals they eat are all part of which level of organization? (Select all that apply.)
dividual organisms
Answer:
the answer is ecosystem i believe.
Answer:
ecosystem
Explanation:
Can someone help pls! I’m very confused on this!!
What does it mean when a cell is multicellular?
options:
A.) Multicellular organisms are simple. They contain cytoplasm, ribosomes, DNA and a cell membrane
B.) Multicellular organisms are made of many cells and have specialized shapes that allow them to perform specific functions
C.) Multicellular organisms are made of one cell and have simple shapes that allow them to perform multiple functions
D.) Multicellular cells do not come from pre-existing cells.
Answer:
B.) Multicellular organisms are made of many cells and have specialized shapes that allow them to perform specific functions
Explanation:
Multicellular means that there is more than one cell.
Hope this helps!
What rule/principle states that electrons in the same sublevel (p, d, or f) are placed in individual orbitals, before they are paired up, to increase atomic stability?
Aufbau principle
Hund’s rule
Pauli exclusion principle
Answer:
Hunds Rule
Explanation:
The principle states that electrons in the same sublevel (p, d, or f) are placed in individual orbitals, before they are paired up, to increase atomic stability is Aufbau principle, therefore option (a) is correct.
What is Aufbau principle ?
Aufbau principle states that electrons are filled into atomic orbitals in the increasing order of orbital energy level.
According to the Aufbau principle, the available atomic orbitals with the lowest energy levels are occupied before those with higher energy levels.
The rule/principle states that electrons in the same sublevel (p, d, or f) are placed in individual orbitals, before they are paired up, to increase atomic stability is Aufbau principle, therefore option (a) is correct.
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OMG PLEASE HELPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP MEEEEEEEEEEEEEEEEEEEEEEEEEE
Living things respire to stay alive. In the mitochondria, sugar is combined with oxygen to produce energy, water and carbon dioxide. Write the equation of this chemical reaction
Answer:
C6H12O6 + 6O2 → 6CO2 + 6H2O
Explanation:
Cellular respiration occurs in the mitochondria of cells. It is a process in which sugar is combined with oxygen to produce energy, water and carbon dioxide. This is the major process by which energy is released in living organisms.
Aerobic respiration involves a series of chemical reactions. These reactions commence with sugar and oxygen then it produces carbon dioxide and water according to the reaction equation; C6H12O6 + 6O2 → 6CO2 + 6H2O.
Answer: The equation for this Chemical reaction is:
C6H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l) + heat (energy)
Explanation:
Mitochondria is the site of chemical energy conversions for cell activities. In the mitochondria, sugar (chemical energy) is combined with oxygen to produce energy, water and carbon dioxide. The equation for this reaction is already given above.
All living cells need energy for the metabolic processes essential for life. They get this energy from the chemical energy stored in food (sugar).
In this process, oxygen is necessary for the chemical energy in sugar to be converted to carbondioxide, water and release of heat energy. It is therefore an oxidative reaction.
Furthermore, energy is not released in one big step as shown in the above reaction, but in a series of small steps which are catalysed by enzymes. The energy that is released, bit by bit, is stored in adenosine triphosphate (ATP) molecules. The oxidation of glucose to release energy in this manner is known as CELLULAR RESPIRATION. It occurs also in the mitochondria of all living cells.
Which type of galaxy contains mostly new stars because it has lots
of dust and gas
Will mark brainly
AsAP
Bombardier beetles release a burst of hot chemical spray with a popping sound. The chemical is sprayed from a structure present under the belly of the beetles.
Which is the likely advantage of such a behavior?
It allows the beetles to attract mates.
It allows the beetles to move obstacles out of their paths.
It allows the beetles to escape from predators.
It allows the beetles to stay warm in cold conditions.
It allows the beetles to escape from predators
A force of 792 mN is applied to a substance with a mass of 295,000 mg.
Determine the acceleration of the particle.
Answer:
Acceleration = 2.68 m/s² (Approx.)
Explanation:
Given:
Force = 792 mN = 0.792 N
Mass = 295,000 mg = 0.295 kg
Find:
Acceleration
Computation:
Acceleration = Force / mass
Acceleration = 0.792 / 0.295
Acceleration = 2.68 m/s² (Approx.)
