Answer:
Examples of physical change include changes in the size or shape of matter. Changes of state, for example, from solid to liquid or from liquid to gas, are also physical changes. Some of the processes that cause physical changes include cutting, bending, dissolving, freezing, boiling, and melting.
Explanation:
I hope this helps
The molar mass of water (H2O) is 18. 0 g/mol. A sample of water has a mass of 18. 0 g. How many moles of water are contained in this sample? 1. 00 18. 0 36. 0 324.
1 mole of water is contained in a sample of water that has a mass of 18.0 g.
HOW TO CALCULATE NUMBER OF MOLES:
The number of moles of a substance can be calculated by dividing the mass of that substance by its molar mass.
no. of moles = mass ÷ molar mass
According to this question, a sample of water has a mass of 18.0g. The number of moles is calculated as follows:
no. of moles of H2O = 18.0g ÷ 18g/mol
no. of moles of H2O = 1mol
Therefore, 1 mole of water is contained in a sample of water that has a mass of 18.0 g.
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Distance traveled over a period of time is?
Answer:
AVERAGE speed is the total distance traveled divided by the elapsed time.Michael was sitting at his desk one morning. He noticed a small spot of light on the wall
which moved with his arm. What could be causing this spot of light on the wall?
O a) light from the window being refracted
by his watch band
b) light from the window reflecting off the
face of his watch
O c) light from the window being absorbed
by the wall
d) light from his watch refracting on the
wall
Answer:
Light from the window reflecting off the face of his watch <33
a chemical reaction in which bonds are broken is usually associated with
the release of energy
the atomic number is the same as the number of which subatomic particle?
the photo has the question; please help asap ! i’m giving brainliest—i also have more chemistry, honestly i’m about to post a whole bunch of questions
Answer:
The process is to divide the molecules by Avogadro's number (6.02 x 10^23) to get the moles. And since it's specified at STP (standard temperature and pressure) we know that the molar volume would be 22.4L. So we can just multiply the moles by the molar volume in order to get the volume of H2S.
(2.18 x 10^24) / (6.02 x 10^23) = 3.62 moles (rounded)
Now just multiply the moles by the molar volume of STP, 22.4.
3.62 x 22.4 = 81 Liters (rounded) of H2S
Silicone is a type of synthetic compound made of silicon, oxygen, and other elements. There are many different kinds of silicone. One kind is a liquid and is commonly used as a lubricant to reduce friction between moving parts. Unlike petroleum-based lubricants, silicone is nontoxic. However, silicone is more expensive than petroleum-based lubricants.
Which of the following would silicone lubricants most likely be used for?
Explanation:
Liquid-based lubricant
Answer:
study island : food service equipment
Explanation:
Minerals are _______ substances with a fixed crystal structure and a unique chemical composition. Processing ore sometimes involves _______ or grinding minerals. Prehistoric people used _______ for knives and arrowheads. The average American house contains about _______ pounds of minerals. Early _______ used rocks as simple tools as early as 2. 6 million years ago.
Minerals are solid substances with a fixed crystal structure and a unique chemical composition. Processing ore sometimes involves crushing or grinding minerals. Prehistoric people used flints for knives and arrowheads. The average American house contains about 250,000 pounds of minerals. Early Human culture used rocks as simple tools as early as 2. 6 million years ago.
What are minerals?Minerals are solid substances and are characterized by a fixed crystal structure and a unique chemical composition.
Early hominids used rocks as simple tools before the advent of modern civilization where other materials were used.
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Answer:
1. naturally occurring
2. crushing
3. flint
4. 250,000
5. hominids
When a magnesium is heated, it burns in air with a dazzling white flame to form a white powder .What it called?
Balanced Equation –
[tex]\purple{\bf{2Mg + O_2 = 2MgO}}[/tex]
Physical states –
Magnesium → Mg ( In Solid State) Oxygen → [tex]\sf{O_2}[/tex] ( Gaseous State) Magnesium Oxide → MgO ( In Solid State Or White powder)_______________________________________
It is magnesium Oxide MgO2
Find the volume of hydrogen gas that reacts with 200 cm of nitrogen gas
measured at the same temperature and pressure.
N2 + 3H2(g) 2NH3(g)
Answer:
15 L
Explanation:
The important thing to remember about reactions that involve gases kept under the same conditions for pressure and temperature is that the mole ratios that exist between the gases are equivalent to volume ratios.
This can be proven using the ideal gas law equation for two gases kept at a temperature
T
and a pressure
P
.
P
⋅
V
1
=
n
1
⋅
R
⋅
T
→
the ideal gas law equation for the first gas
P
⋅
V
2
=
n
2
⋅
R
⋅
T
→
the ideal gas law equation for the second gas
Divided these two equations to get
P
⋅
V
1
P
⋅
V
2
=
n
1
⋅
R
⋅
T
n
2
⋅
R
⋅
T
This means that you have
n
1
n
2
=
V
1
V
2
→
the mole ratio is equivalent to the volume ratio
In your case, the balanced chemical equation looks like this
N
2(g]
+
3
H
2(g]
→
2
NH
3(g]
The problem tells you that this reaction takes place at constant temperature and pressure. You don't need to know the exact values, you just need to know that they are constant for all three chemical species.
You can thus say that since you have a
1
:
3
mole ratio between nitrogen gas and oxygen gas, you will also have a
1
:
3
the volume ratio between these two gases
n
N
2
n
H
2
=
V
N
2
V
H
2
=
1
3
The volume of hydrogen gas needed to react with that much nitrogen gas will thus be
5.0
L N
2
⋅
3
L H
2
1
L N
2
=
15 L H
2
Which statement does not identify a characteristic of antibodies?
A They are produced by the body in response to the presence
of foreign substances.
B They may be produced in response to an antigen.
© They are nonspecific, acting against any foreign substance in
the body.
D They may be produced by white blood cells.
Answer:
they are produced by the body in response to the presence of foreign substance
(b) at 400k both compounds are gases. at this temperature, which compound, ch4(g) or ccl4(g), behaves more like an ideal gas? justify your answer, including reasoning about both molecules.
CH4 has more ideal gas behavior than CCl4 due to its higher intermolecular interaction.
We must note that ideal gases have minimal interaction with each other. Hence, in deciding which gas has ideal gas behavior, we have to consider the gas that has the least degree of intermolecular interaction.
However, the both gases contain nonpolar molecules but CCl4 has a greater molecular mass and has more intermolecular interaction than CH4 hence CH4 has greater ideal gas behavior than CCl4.
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the expression of potential energy , i.e., P.E.=mgh , where the terms used have their usual meaning
Gravitational Potential energy:
The Gravitational potential energy of
an object at a point above the ground
is defined as the work done in raising
it from the ground to that point against
gravity.
Consider an object of mass "m" is raised
to heighth from the ground.
A force is required to do this. the
minimum force required to raise the
object is equal to the weight of the
object[mg]
The object gains energy equal to the
work done on it. Let the work done on
the object against gravity be "w"
WorkDone=W= Force x displacement
=mgxh
..W=mgh
since the workdone on the object is
equal to "mgh" an energy equal to "mgh"
units is gained by object.This is the
potential energy of object at height "h"
.. P.E=mgh
Question 1 of 11 The graph shows the change in temperature of a sample of water in a closed system as thermal energy is added over time. 150°C 100°C TELE Temperature (°C) 50°C 0°C -50°C 10 20 30 40 Time (min) 50 60 What happens in the water during changes of state? A. Its particles move at a lower speed B. Its particles maintain a constant speed. c. Its temperature varies constantly D. Its temperature increases slowly
Answer:
B. Its particles maintain a constant speed
Explanation:
Just did it :D
The graph shows the change in temperature of a sample of water in a closed system as thermal energy is added over time. 150°C 100°C Temperature (°C) 50°C 0°C -50°C 10 20 30 40 Time (min) 50 60 during changes of state water particles maintain a constant speed. Therefore, option B is correct.
What is thermal energy ?The term thermal energy is defined as the energy contained within a system that is responsible for its temperature.It is formed when the atoms and molecules in a substance vibrate faster due to a increase in temperature.
The examples of thermal energy sources are fossil fuels like natural gas, coal and oil, and solar heat, heat pump electric heat, and geothermal heat.
Thus, during changes of state water particles maintain a constant speed, option B is correct.
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which acids are found In lemon and milk
Answer:
lemon- citric acid
milk- lactic acid
Answer:
lemon=citric and malic acids.
milk=Lactic Acid
Explanation:
15 POINTS AND BRAINLIEST
Martin hooked up the following circuit. He noticed that the light did not turn on. How could he fix the circuit to make it work?
A. Martin needs to have one wire coming from one side of the battery to the light bulb and one wire coming from the other side to the switch. To make a closed circuit, he can use a wire to connect the switch to the light bulb.
B. Martin needs to connect one wire from the switch to the battery and one wire from the battery to the light bulb. When he does this, it will be a closed circuit that allows electricity to flow.
C. Martin needs to turn the battery around. When he does this, it will become a closed circuit allowing electricity to flow through the circuit in a loop.
D. The switch is in the open position. If Martin lifts the switch, it will close the circuit and electricity will flow from the battery to the light bulb in a loop.
Question 17(Multiple Choice Worth 2 points)
(07.01 MC)
Answer: maybe D sorry if it's wrong
Explanation:
Which pair of elements are in the same period?Hg & PbLi & NaB & ClO & As
Answer:
Hg Pb are in one, Li and B and O are in one, and NaCl are in one, As is alone
Explanation:
Periods are horizontal
Hope this helps!
a) how many moles of o2 are needed to burn 1.50 mol of c8h18?
Answer:
Moles of oxygen needed to burn given amount of octane is 16.875 moles.
Explanation:
Why are the three atoms are isotopes of magnesium
Answer:
Magnesium is a naturally ubiquitous; (appearing & found evrywhere) element and has three naturally occurring stable isotopes, 24Mg, 25Mg and 26Mg, with relative abundance of 78.99%, 10.00% and 11.01%, respectively.
However, they differ only because a 24Mg atom has 12 neutrons in its nucleus, a 25Mg atom has 13 neutrons, and a 26Mg has 14 neutrons.
Explanation:
how many molecules of atp are produced as a result of glycolysis
Answer:
2 ATP molecules are produced
Answer:
2 ATP molecules of ATP are produced
why does water boil at a lower temperature at higher altitudes
A teacher places a cup of coffee onto an electronic balance at the front of the science laboratory. The teacher then adds three large teaspoons of sugar to the coffee. The volume of the coffee does not appear to increase. What happens to the mass displayed on the front of the balance?
Answer:
it will be same as before
Answer:
The mass on the balance stays the same
Explanation:
.
how does the number of valence electrons change as you move to the right across the periodic table?
Answer:
The number of valence electrons goes up by one each time you move
The condition of acidosis can also cause ____________ because the higher H concentration diffuses to the ICF, pushing K towards the ECF.
Answer:
Hyperkalemia
Explanation:
The condition of acidosis can also cause Hyperkalemia because the higher H concentration diffuses to the ICF, pushing K towards the ECF.
Which term describes a change that occurs with no new substances being formed?
A. Energy change
B. Bond change
C. Physical change
D. Chemical change
C. physical change
Explanation:
That's the answer
noble gases are used in many situations where a safe and constant environment must be maintained. for example, helium is used to provide a protective atmosphere for making fiber optics and semiconductors. argon is used to fill incandescent and flourescent light bulbs to prevent oxygen from corroding the hot filament. why are noble gases used in these situations?
Answer:
Noble gases have a complete valence electron shell making them stable and nonreactive.
Explanation:
Examine the model of the different states of matter. Select ALL of the statements that accurately describe the particles in differing states. A) Gases contain less particles. B) Gases have the greatest kinetic energy. C) Energy is removed in the change from a liquid to a gas. D) Energy is added to change from a solid to a liquid state. E) In a solid, particles are so closely packed that they can only vibrate in place.
The statements which accurately describe the particles in differing states include:
Gases have the greatest kinetic energy.Energy is added to change from a solid to a liquid state. In a solid, particles are so closely packed that they can only vibrate in place.Gases have the greatest kinetic energy which explains why its particles
move very rapidly and randomly when compared to other states of matter.
Conversion from solid to liquid or liquid to gas requires more energy being
added.
The particles in solids are tightly packed with very restricted movements
which is why they are able to vibrate at a place.
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is it NaCO3 or Na2CO3?
Which statement describes one feature of Rutherford model of the atom
[tex] \huge{ \color{magenta}{ \fcolorbox{magenta}{black}{ \huge{ \color{white}{ \fcolorbox{aqua}{black}{♡Answer♡ }}}}}}[/tex]
The Rutherford model shows that an atom is mostly empty space, with electrons orbiting a fixed, positively charged nucleus in set, predictable paths.
what activity occurs in the process of photosynthesis
Answer:
Photosynthesis is the process in which light energy is converted into chemical energy in the form of sugars. In a process powered by light energy, glucose (and other sugars) molecules are created from water and carbon dioxide, while oxygen is released as a by-product.Explanation:
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