Changes in the total amount of thermal energy provide evidence that chemical reactions have taken place. A chemical reaction in which energy has been absorbed is known as a(n):
Select one:
physical reaction.
endothermic reaction.
reversible reaction.
exothermic reaction.
Answer:
B. endothermic reaction
Explanation:
4) How many liters are needed for a 5.1 Molar solution containing 2.3 moles of NaCl?
moles =
Molarity =
Liters =
PLZZZ HELP ME WITH THIS
Answer:
1) The mole ratio of KClO₃ to 3O₂ is 2:3
The reciprocal of the mole ratio of KClO₃ to 3O₂ is 3:2
2) The mole ratio of K to NaNO₃ is 1:1
The reciprocal of the mole ratio of K to NaNO₃ is 1:1
Explanation:
The mole ratio (also known as mole-mole ratio) of two compounds involved in a chemical reaction, is the ratio of the number of moles of the compounds in the reaction which can be obtained from the coefficients of the compounds in the balanced chemical reaction
The mole ratio of compound A to compound B = A:B = A/B
1)The given chemical reaction can be expressed as follows;
2KClO₃ → 2KCl + 3O₂
Therefore;
[tex]The \ mole \ ratio \ of \ KClO_3 \ to \ O_2 = \dfrac{2 \ moles \ of \ KClO_3}{3 \ moles \ of \ O_2} = \dfrac{2}{3} = 2:3[/tex]
[tex]The \ reciprocal \ of \ the \ mole \ ratio \ of \ KClO_3 \ to \ O_2 = \dfrac{3 \ moles \ of \ O_2}{2 \ moles \ of \ KClO_3} = \dfrac{3}{2} = 3:2[/tex]
2) In the reaction NaNO₃ + K → Na + KNO₃
The mole ratio of K to NaNO₃ = 1:1
Therefore;
The reciprocal of the mole ratio of K to NaNO₃ = 1:1
helpp
simplify the meaning of these
circuit
electric current
voltage difference
ohms law
resistance
Answer:
circuit
electric current
voltage difference
ohms law
resistance
Explanation:
Circuit - a roughly circular line, route, or movement that starts and finishes at the same place.
Electric current - A net unidirectional movement of electrons, or other charge carriers, caused by a potential difference
Voltage difference - A potential difference of one Volt is equal to one Joule of energy being used by one Coulomb of charge when it flows between two points in a circuit.
Ohms law -a law stating that electric current is proportional to voltage and inversely proportional to resistance.
Resistance - The refusal to accept or comply with something; the attempt to prevent something by action or argument.
The measured pOH of a solution is 5.5. What is the hydrogen ion, [H+ ],
concentration?
First, calculate pH using the pOH:
14 - pOH = pH --> pH = 14 - 5.5 = 9.5
[H+] = 10^-pH = 10^-9.5 = 3.2 x 10^-10 M ≈ 3 x 10^-10 M (The answer should technically only be one sig fig, since the pOH is given to only one decimal place).
A star's mass determines the A.length of its lifecycle b.location of the star c.galaxy it belongs to. D.shape of the star
Answer:
A.length of its lifecycle
Explanation:
A star will go through evolutionary stages depending on their initial mass. These stages are determined by the internal structure of the star and how it produces energy. Therefore, scientists may use the HR diagram to determine the length of the stars lifecycle depending upon its initial mass.
Which is not a property of a gas? * exert pressure high density High compressibility readily soluble
Explanation:
A gas is state of matter in which there is large intermolecular distance and hence, a weaker molecular force of attraction in comparison to solids and liquids. therefore, it impart certain properties to gases which are uncommon in solids and liquids
Properties of a gas includes:
Exert pressure on the container
Highly compressible
Low density
and readily soluble in other mediums
Hence, high density is not a property of a gas.
Height
O
Genetic
O Environmental
O Both
Answer:
its both because your hight can change if u do exercises
Hope it helped.
when Henry mosléy came up with he's own atomic number?
I WILL MARK AS BR*NLIST IF YOU CORRECT ANSWER
Answer:
1911 is when he made it
Explanation:
Moseley's law provided a reasonably complete experimental set of data that supported the (new from 1911) conception by Ernest Rutherford and Antonius van den Broek of the atom, with a positively charged nucleus surrounded by negatively charged electrons in which the atomic number is understood to be the exact physical number of positive charges (later discovered and called protons) in the central atomic nuclei of the elements.
Which one of the following compounds is insoluble in water?
a) Na2CO3
b) K2SO4
c) Fe(NO3)3
d) ZnS
Answer:
The answer is Na2CO3.Option a
Ahhhh someone help me with this
Answer:
3.6g
Explanation:
2 moles of water gives 1 mole of oxygen
2(h2o)=1(o2)
2(molar mass of h2o)=1(molar mass of oxygen molecule)
2(18)=1(16×2)
36=32
3.6=x
cross multiply
3.6×32=36× x
115.2=36x
x=115.2÷36
x=3.6g
What happens during high tide?
a.The tidal range is at its minimum in a location.
b.The tidal range is at its maximum in a location.
c.The water level in the ocean rises to above average water level.
D.The water level in the ocean drops to below average water level.
Answer: c
Explanation:
How do you find how many electrons are in a atom?
Answer:
To determine how many total electrons there are, add the amount of charge to the atomic number. In this case, there are fewer protons than electrons. For example, N 3- has a -3 charge which means it has 3 more electrons than a neutral nitrogen atom. Nitrogen’s atomic number is 7, therefore this ion has 10 electrons.
HOPE IT HELPS
HAVE A NICE DAY
Explanation:
What is the scientific method? *
a. A series of steps used by scientists to investigate an hypothesis
b. A series of steps used to determine which chemicals are good for use
c. A series of steps used to tell how life began on earth
d. A series of steps used to by scientists to find about technology
help please see attached file
Answer:
balanced equation of glucose
6CO2 + 6H2O----------C6H12O6 + 6O2
in the presence of sun light.
Need help on this question asap please
Answer:
The correct answer is - 14.
Explanation:
In the given molecular formula of the aluminum sulphite which is Al2(SO3)3, this molecular formula there different type of elements are bonded together to form this compound each element has a specific number of atoms present. This compound has three elements that are aluminum, sulfur, and oxygen and the atoms are present are:
Al = 2 atoms represented by subscript
S = 3 atoms represented as whole subscripts of sulfite
O = 9 atoms 3 inside bracket and 3 outside of bracket that multiplies.
Thus, total number of atoms are 2+3+9 = 14
The image shows the mouth of a Tasmanian devil. The Tasmanian devil has four distinctive long teeth near the front of its mouth. Based on their shape, what are these teeth mostly like used for?
A.
holding and tearing meat
B.
crunching and crushing bone
C.
grinding up plant material
D.
rooting in soil for worms
Answer:
same as the answer of her
Explanation:
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Balance the following equation
C₂H₆O + O₂ → CO₂ + H₂O
Answer:
C2H6O + 3O2 - > 2CO2 + 3H20
2.00g of Copper wire was added to 50.0 mL of a 0.050M solution of Silver Nitrate. The reaction
produced solid silver and aqueous copper II Nitrate. The silver precipitate was collected and
dried. It was determined that the mass of the silver precipitate was 0.24 g. Use this information
to determine the theoretical yield, limiting reactant, and percent yield.
Answer:
See explanation
Explanation:
Now, the equation of the reaction is;
Cu(s) + 2AgNO3(aq) --------> Cu(NO3)3 (aq) + 2Ag(s)
Number of moles of silver precipitate = 0.24/108 g/mol= 0.0022 moles
Number of moles of AgNO3 = 50/1000 * 0.050 = 0.0025 Moles
If 2 moles of AgNO3 yields 2 moles of Ag
Then 0.0025 moles of AgNO3 yields 0.0025 * 2/2 = 0.0025 moles of Ag
Number of moles of Cu = 2.00g/63.5 g/mol = 0.03 moles
If 1 mole of Cu yields 2 moles of Ag
0.03 moles of Cu yields 0.03 moles * 2/1 = 0.06 moles of Ag
Hence AgNO3 is the limiting reactant
Theoretical yield of Ag = 0.0025 moles of Ag * 108 = 0.27 g
Actual yield of Ag = 0.24 g
Percent yield = actual yield/theoretical yield * 100
Percent yield = 0.24/0.27 * 100
Percent yield = 88.8%
give an example of how an organism can use surface tension?
Answer:Insects, such as water striders, and spiders, such as fisher spiders, can glide or scamper across the surface of water. These critters are small enough that their weight can be supported almost entirely by surface tension, the relatively weak forces that hold water molecules together.
Explanation:
Answer:
Examples of surface tension Water striders are able to walk on top of water due to a combination of several factors. Water striders use the high surface tension of water and long, hydrophobic legs to help them stay above water. Water striders use this surface tension to their advantage through their highly adapted legs and distributed weight.
Explanation:
pls mark brainliest
If 3.91 moles of H2 were used, how many moles of NH3 would be made?
HELP PLEASE ASAP
N + H2 → NH3
balance the equation
2N + 3H2 → 2NH3
3H2 → 2NH3
3 : 2
3.91 ÷ 3 = 1.303 mol
1.3 × 2 = 2.606 mol
Which traits does the common garter snake have that might be adaptive for the environment where it lives?
Answer:
As the garter snake can be found almost in any kind of habitat, what makes them be able to survive in any environment include:
1. They hibernate to increase their chances of survival in unfavorable weather conditions.
2. They can blend with the background of any environment especially grass to escape being eaten.
3. They produce an odor that is usually unpleasant especially when about to be attacked.
Explanation:
The garter snakes are distinguished by the three stripes running the length of their body and can often be found in forests, places that are even close to water bodies, and almost any place, even in holes.
Answer:
Because it'll live in the desert!
Explanation:
It probably won't survive on time!
Do you
think that the Nitrogen cycle has a negative or positive
impact on the environment?
Answer:
Nitrogen, the most abundant element in our atmosphere, is crucial to life. Nitrogen is found in soils and plants, in the water we drink, and in the air, we breathe. It is also essential to life: a key building block of DNA, which determines our genetics, is essential to plant growth, and therefore necessary for the food we grow. But as with everything, balance is key: too little nitrogen and plants cannot thrive, leading to low crop yields; but too much nitrogen can be toxic to plants, and can also harm our environment. Plants that do not have enough nitrogen become yellowish and do not grow well and can have smaller flowers and fruits. Farmers can add nitrogen fertilizer to produce better crops, but too much can hurt plants and animals, and pollute our aquatic systems. Understanding the Nitrogen Cycle—how nitrogen moves from the atmosphere to earth, through soils, and back to the atmosphere in an endless Cycle—can help us grow healthy crops and protect our environment.
Explanation:
When calcium chloride is added to a sample of water, the boiling point will _________. A. increase B. decrease C. not change D. first decrease, then increase
Answer:
C
Explanation:
If you add salt to water, its boiling point increases.
When calcium chloride is added to a sample of water, the boiling point will increase. Option A is correct.
What is boiling point?The boiling point of the liquid is the temperature at which the vapor pressure of a given liquid equals the external pressure or atmospheric pressure surrounding the given liquid.
The calcium chloride is added to a sample of water it releases the some amount heat and become exothermic and the boiling point will increase due to the reaction of water and calcium chloride.
Therefore, when calcium chloride is added to a sample of water, the boiling point will increase. Option A is correct.
Learn more about boiling point, here:
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Volcanic eruptions can be very dangerous for nearby human and animal populations. One danger is that lava and ash may bury habitats. What is another danger during a volcanic eruption?
A.
Lava or hot debris may start fires.
B.
Lava flows may cause tsunamis.
C.
Volcanic eruptions always cause flooding.
D.
Volcanic eruptions always cause high winds.
Answer:
B. Lava flows may cause tsunamis.
2. A chef fills a 100 ml container with a 83.5 g of cooking oil.
What is the density of the oil?
Density (ρ) = 835 kilogram/cubic meter
Steps:
ρ =
m
V
=
83.5 gram
100 milliliter
= 0.835 gram/milliliter
= 835 kilogram/cubic meter
1, 2, or 3...help please
Answer:
molecular so number 3. ...
How many spirals does a DNA molecule have?
Answer:
two
Explanation:
2
Answer:
two
Explanation:
nucleic acids are made up of chains of many repeating units called nucleotides. the dna molecule consists of two such chains that spiral around an imaginary axis to form a double helix (spiral.)
hope this helps :)
have a nice day !!
The temperature of a sample of gas in a steel tank at 60.0 kPa is increased from -105.0°C to 26.0
*C. What is the final pressure inside the tank?*
(
Answer:
106.785 kPa, I believe this is correct!
Explanation:
21. The formation of an ionic bond involves the a transfer of electrons. b. transfer of neutrons. c. transfer of protons. d. sharing of electrons.
Answer:
I think its C but if its not try A then
Explanation: