Ice melts to form water. And water freezes to form ice. Choose the TRUE statement about these changes.
A. Both melting and freezing are physical changes.
B. Both melting and freezing are chemical changes.
C. Melting is a physical change while freezing is a chemical change.
D. Melting is a chemical change while freezing is a physical change.
Answer:
A. Both freezing and melting are physical changes.
Explanation:
Even if you were to freeze water, the molecules are still water molecules, and vise versa with melting it.
Answer: Option A) Both melting and freezing are physical changes.
Explanation:
A physical change is one which is easily reversible and in which no new substances are formed.
Hence, since ice melts to form water (melting), and water freezes to form ice back (freezing), both melting and freezing are easily reversible and do not form new products.
Thus, both melting and freezing are physical changes.
If you visited a virtual Newton’s Cradle website or played with the real device, you might have noticed that after a few swings, the balls slow down. The height they reach gets shorter and shorter until they finally stop moving. If energy is transformed from one type to the other and transferred between the different balls in the device, why does the motion in Newton’s Cradle finally stop? (Hint: Think about something you decided to ignore earlier in the reading.)
Final answer:
The motion in Newton's Cradle stops due to friction and air resistance, which convert the system's kinetic and potential energy into thermal energy, eventually causing the balls to stop swinging.
Explanation:
The motion of Newton's Cradle ultimately stops because of the effects of friction and air resistance, which are forms of dissipative forces. These forces act to gradually convert the kinetic energy and potential energy of the swinging balls into thermal energy, which is dissipated into the environment. While kinetic energy is transferred from one ball to the next in the cradle, a small amount of energy is lost with each collision and swing due to these forces, ultimately causing the balls to come to a rest.
In the idealized physics examples, such as a perfectly elastic collision where no kinetic energy is lost, the motion would continue indefinitely. However, in the real world, due to non-conservative forces like friction and air resistance, kinetic energy is not perfectly conserved in collisions and is instead transformed into other forms of energy, such as heat. This gradual loss of energy to the surroundings is why the height the balls reach in Newton's Cradle decreases over time, and they eventually stop moving.
Even though the neighborhood shown by the green star was not next to any of these fires, how was the neighborhood affected by them?
A)
The heat generated by these fires made the temperatures in the surrounding areas increase.
B)
The smoke produced by these fires were carried by strong winds and made the air hard to breathe.
C)
The chemicals that were released by these fires cleared out the air and improved overall visibility.
D)
The air around the neighborhood was cooled due to the fire sucking the heat out of the surrounding air.
Answer:
B
Explanation:
B is the only possible answer that makes much sence, smoke is very toxic and it makes it hard to breath and is bad for your lungs
This chart shows the experimental design of four students who are all observing what kind of bird seed birds tend to eat
more often
Student 1 Student 2 Student 3 Student 4
- Performed the - Repeated the - Repeated the - Repeated the
experiment experiment 5 experiment 2 experiment 5
once
times
times
mes
- Used the same - Used the same - Used the same - Used the same
area. same time area, different area, different area. same time
of day, and time of day, and time of day, and of day, and
same amount of different amount different amount same amount of
seeds
of seeds of seeds
seeds
Which student is the most likely to have reproducible results?
Student 1
Student 2
Student 3
Student 4
Answer:
student 2 i took the quiz
Explanation:
4. A simple sugar's properties result from
a. Its ratio of amylose to amylopectin
b. How atoms are arranged in its molecules
C. The type of plant that produced it
d. The degree of crystallization
Answer:
b. how atoms are arranged in it's molecules
What temperature would 3.54 moles of xenon gas need to reach to exert a pressure of 1.57 atm at a volume of 34.6 l
Answer:
186.9Kelvin
Explanation:
The ideal gas law equation is PV = n R T
where
P is the pressure of the gas
V is the volume it occupies
n is the number of moles of gas present in the sample
R is the universal gas constant, equal to 0.0821 atm L /mol K
T is the absolute temperature of the gas
Ensure units of the volume, pressure, and temperature of the gas correspond to R ( the universal gas constant, equal to 0.0821 atm L /mol K )
n = 3.54moles
P= 1.57
V= 34.6
T=?
PV = n R T
PV/nR = T
1.57 x 34.6/3.54 x 0.0821
54.322/0.290634= 186.908620464= T
186.9Kelvin ( approximately to 1 decimal place)
Which best describes nuclear fusion?
A. It produces heavier elements.
B. It creates abundant radioactive material.
C. It causes the collision of alpha particles.
D. It transforms energy into mass.
Answer:
The answer is C. It causes the collision of alpha particles.
Explanation:
Nuclear fusion is a process that produces heavier elements by combining lighter elements.
Explanation:Nuclear fusion is a process in which two or more atomic nuclei come together to form a single, more massive nucleus, releasing a large amount of energy in the process. The answer to the question is It produces heavier elements. During nuclear fusion, lighter elements combine to form heavier elements. This process is responsible for the energy emitted by the sun and other stars. It does not create abundant radioactive material as nuclear fusion reactions do not produce long-lived radioactive waste like nuclear fission reactions. It does not cause the collision of alpha particles, as alpha particles are involved in nuclear decay processes. It also does not transform energy into mass, as mass is directly involved in nuclear reactions.
Hence the answer is Option A.
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What is the molality of a solution containing 0.25 g
of dichlorobenzene (C6H4Cl2) dissolved in 10.0 g of
cyclohexane (C6H12)?
Answer : The molality of solution is, 0.170 mole/kg
Explanation : Given,
Mass of dichlorobenzene = 0.25 g
Mass of cyclohexane = 10.0 g
Molar mass of dichlorobenzene = 147.01 g/mole
Formula used :
[tex]\text{Molality}=\frac{\text{Mass of dichlorobenzene}\times 1000}{\text{Molar mass of dichlorobenzene}\times \text{Mass of cyclohexane (in g)}}[/tex]
[tex]\text{Molality}=\frac{0.25g\times 1000}{147.01g/mole\times 10.0g}=0.170mole/kg[/tex]
Therefore, the molality of solution is, 0.170 mole/kg
Which of the following is a chemical change?
A.)Butter melts
B.)Metal rusts.
C.)Water boils.
D.)Things dissolve.
Answer:
B.) Metal Rusts.
Thank You ☺️ ☺️.
☆ ★ Make It Brainlist Answer Please.....If a student needs to make exactly 2.5 liters of
a 1.25 M solution of acetic acid from the 12.0
M stock solution in the chemistry closet, what
must the student do?
If a substance has a half life of 45 days, how much of the original substance would be left after 90 days?
After 90 days, two half-lives of a substance with a 45-day half-life will have passed, resulting in one-fourth or 25% of the original amount remaining.
If a substance has a half-life of 45 days, after 90 days, there would have been two half-lives that passed. During each half-life, half of the remaining substance decays. So after the first 45 days, you would be left with one-half of the initial amount, and after another 45 days (which totals 90 days), you would be left with half of that amount. This means after 90 days, one-fourth of the original substance would be left.
To calculate this, you can use the equation for exponential decay:
Final amount = Initial amount × [tex]1/2^{number of half lives}[/tex]
In this case, the number of half-lives is 90 days divided by the half-life of the substance, which is 45 days:
Number of half-lives = 90 days / 45 days per half-life = 2 half-lives
Therefore, the remaining amount of the substance would be:
Final amount = Initial amount ×(1/2)² = Initial amount ×1/4
This results in the correct answer that after 90 days, you'd have 25% or one-fourth of the original amount of the substance remaining.
3.25 * 10 ^ 24 molecules of dinitrogen pentoxide would be how many moles?
Answer: 5.4 moles
Explanation:
Dinitrogen pentoxide has a chemical formula of N2O5
Now, based on Avogadro's law:
1 mole of any substance has 6.02 x 10^23 atoms
So, 1 mole of N2O5 = 6.02 x 10^23 molecules
Z moles of N2O5 = 3.25 x 10 ^ 24 molecules
To get the value of Z, cross multiply:
(3.25 x 10^24 molecules x 1mole) = (6.02 x 10^23 molecules x Z moles)
3.25 x 10^24 = (6.02 x 10^23 x Z)
Z = (3.25 x 10^24) ➗ (6.02 x 10^23)
Z = 5.4 moles
Thus, there are 5.4 moles of Dinitrogen pentoxide.
Answer:
5.39
full answer: 5.396878114
Explanation:
divide 3.25*10^24 over 6.022*10^23(which is a mole of anything in particles)
what ions represent an acid? What ions represent a base?
Explanation:
acid - An acid is a substance or compound that releases hydrogen ions (H+) when in solution. ...
A base is a substance that releases hydroxyl ions (OH-) when in solution. ...
Figure 2.4. ...
pH is a unit of measurement of the concentration of hydrogen ions (H+) and hydroxyl ions (OH-) in an aqueous (water) solution
base - H 3O + is called a hydronium ion, and it makes things acidic. OH - is called a hydroxyl ion and it makes things basic.
If the temperature of a gas changes, but the number of moles and volume remain constant, which of the following values must also change?
Density
Pressure
Number of atoms
Mass
If the temperature of a gas changes, but the number of moles and volume remain constant, Pressure also changed. Therefore, option B is correct.
What do you mean by pressure ?The amount of force exerted per area is defined as pressure. To generate a large amount of pressure, you can use either a large force or a force applied over a small area.
Pressure is a situation that can have serious consequences if you don't perform well; thus, performing under pressure. It appears to be a life-or-death situation: your reputation, a relationship, your success, or your safety are all at stake. Your inability to distinguish between stress and pressure can be detrimental.
Pressure changes when the temperature of a gas changes but the number of moles and volume remain constant.
Thus, option B is correct.
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Sample Response: Jade's error occurs in the top-right square of the Punnett square. In this square, she identifies the phenotype as freckles, but to have freckles, the offspring must have at least one dominant allele. The offspring in this box are ff. Because there is no dominant allele present, the offspring will not have freckles.
What did you include in your response? Check all that apply.
Jade’s error occurs in the top-right square of the Punnett square.
Jade identifies the phenotype as freckles.
To have freckles, the offspring must have at least one dominant allele.
The offspring in this box are ff.
There is no dominant allele present, so the offspring will not have freckles.
Answer:
all of them
Explanation:
Answer:
1,2,3,4,5
Explanation:
plz brainlest me
A 25 g sample of water releases 2913 J as it cools from 50.0°C. Calculate the final temperature of the water. (Water’s specific heat capacity is 4.184 J/g°C) (round answer to 2-3 sig figs)
Answer:
The final temperature is 22.2°C
Explanation:
Step 1:
Data obtained from the question. This includes the following:
Mass (M) = 25g
Heat (Q) = 2913 J
Initial temperature (T1) = 50.0°C
Final temperature (T2) =?
Specific heat capacity (C) = 4.184J/g°C
Step 2:
Determination of the final temperature.
The final temperature can be obtained as follow:
Q = MC(T1 – T2).. Since we are cooling
2913 = 25 x 4.184 (50 – T2)
2913 = 104.6 (50 – T2)
Divide both side by 104.6
50 – T2 = 2913/104.6
50 – T2 = 27.8
Collect like terms
T2 = 50 – 27.8
T2 = 22.2°C
The final temperature is 22.2°C
Oceanic crust is
-
made mostly of granite
made mostly of limestone and salt
thinner than continental crust
thicker than continental crust
Answer:
It is thinner than the continental crust.
Explanation:
The oceanic crust is largely made up of basalt, a dense type of rock that forms from solidified lava, and it is thinner than the continental crust that is mainly composed of granite.
Explanation:The oceanic crust is primarily composed of a type of rock known as basalt. This is a dark, dense igneous rock that forms due to the cooling and solidifying of lava. In contrast to the granitic composition of the continental crust, the oceanic crust's basaltic composition is denser but thinner than the continental crust. Hence, the oceanic crust is not made mostly of granite, limestone or salt, but rather, it is predominantly basalt and it is not thicker but thinner than continental crust.
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The reaction 2NO (g) → N2 (g) + O2 (g) has a ΔH =−180.5 kJ .
How much heat will be required to produce 44.8 L of NO by the reverse reaction?
180.5 kJ
301 kJ
322.3 kJ
644 kJ
Answer: the answer is 180.5 i am 100% i just did the test
The heat that should be required to produce 44.8 L of NO by the reverse reaction is 180.5 J.
What is heat?The heat energy should be converted from one body to the another due to which there should be the difference in the temperature. In the case when two bodies should be at the different temperature so here the energy should be transferred i.e. the heat should be flows i.e from the hotter body to the colder.
hence, The heat that should be required to produce 44.8 L of NO by the reverse reaction is 180.5 J.
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If a dolphin is producing a vocalization with a frequency of 35 Hz, traveling at 1470 m/s, what is the wavelength of the sound?
Answer:
42
Explanation:
Divide the distance by the time.
If a dolphin is producing a vocalization with a frequency of 35 Hz, traveling at 1470 m/s, then wavelength of sound is 42m.
How do we calculate wavelength?Wavelength of sound will be calculated by using the below formula as:
λ = υ / f, where
υ = velocity or speed of sound = 1470 m/s
f = frequency of wavelength = 35 Hz
On putting values we get
λ = 1470 / 35 = 42m
Hence resultant wavelength of sound is 42m.
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If the pressure changes from 1 atm to 3 atm, what does the volume of 30 L change to
Answer: 10L
Explanation:
Given that:
Initial pressure P1 = 1 atm
New pressure P2 = 3 atm
Initial volume V2 = 30 L
New volume V2 = ?
Since pressure and volume are involved, apply the formula for Boyle's law
P1V1 = P2V2
1 atm x 30L = 3 atm x V2
30 atm L = 3 atm x V2
V2 = (30 atm L / 3 atm)
V2 = 10L
Thus, volume changed to 10 liters
According to the chart, which substance has the lowest OH' concentration?
A)
urine
lemon juice
tomato juice
D)
black coffee
Answer:
lemon juice
Explanation:OH is in bases and lemon juice is an acid
What is the chemical name for the compound If5
Answer:
Iodine pentafluoride
Explanation:
Answer:
Iodine pentafluoride
What net ionic equation describes the reaction that occurs when AI2(SO4)3(aq)andNa3PO4(aq)are mixed together?
Answer: chemical reaction
Explanation:
Al3+(aq)+PO4^3-(aq)+3SO4^2-(aq0 --> 3AlPO4(s)+3Na+(aq)
PLEASE HELP!CHEMISTRY QUESTION
On Venus the atmospheric pressure is 2700 mmHg and nitrogen gas makes up 3.0 % of the atmosphere. What is the partial pressure of nitrogen on Venus? mmHG
Answer: The partial pressure of nitrogen on Venus is 81 mmHg
Explanation:
To calculate the partial pressure of the gas, we use the equation given by Raoult's law, which is:
[tex]p_{A}=p_T\times \chi_{A}[/tex]
where,
[tex]p_A[/tex] = partial pressure of nitrogen gas = ?
[tex]p_T[/tex] = total pressure = 2700 mmHg
[tex]\chi_A[/tex] = mole fraction of nitrogen gas = 3.0 % = 0.03
Putting values in above equation, we get:
[tex]p_{N_2}=2700mmHg\times 0.03\\\\p_{N_2}=81mmHg[/tex]
Hence, the partial pressure of nitrogen on Venus is 81 mmHg
Question 1 (1 point)
HOW MANY moles of Neon would be contained in 4.0 L of neon gas at 560 kPa and 127 C?
Answer:
0.674 mol
Explanation:
Step 1:
Data obtained from the question.
Volume (V) = 4 L
Pressure (P) = 560 kPa
Temperature (T) = 127°C
Number of mole (n) =?
Step 2:
Conversion to appropriate unit.
For pressure:
101.325 KPa = 1 atm
Therefore, 560 kPa = 560/101.325 = 5.53 atm
For temperature:
Temperature (Kelvin) = temperature (celsius) + 273
temperature (celsius) = 127°C
Temperature (Kelvin) = 127°C + 273 = 400K
Step 3:
Determination of the number of mole of Neon.
The number of mole of Neon can be obtained by using the ideal gas equation as follow:
Volume (V) = 4 L
Pressure (P) = 5.53 atm
Temperature (T) = 400K
Gas constant (R) = 0.082atm.L/Kmol
Number of mole (n) =?
PV = nRT
5.53 x 4 = n x 0.082 x 400
Divide both side by 0.082 x 400
n = (5.53 x 4) /(0.082 x 400)
n = 0.674 mol
The number of mole of Neon is 0.674 mol
To find the number of moles of Neon in 4.0 L of neon gas at 560 kPa and 127 °C, the ideal gas law is used, and approximately 0.674 moles of Neon are found.
The student has asked how many moles of Neon would be contained in 4.0 L of neon gas at 560 kPa and 127 °C. To answer this question, we will use the ideal gas law, which can be stated as PV = nRT where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature in Kelvin.
First, convert the temperature from Celsius to Kelvin:
T(K) = 127 °C + 273.15 = 400.15 KConvert pressure from kPa to atm:
P(atm) = 560 kPa / 101.325 kPa/atm = 5.528 atmThe ideal gas constant, R, is 0.0821 L·atm/mol·K.
Now, rearrange the ideal gas equation to solve for n (moles):
n = PV / (RT)Plugging the values in, we get:
n = (5.528 atm × 4.0 L) / (0.0821 L·atm/mol·K × 400.15 K)n ≈ 0.672 moles of NeonTherefore, there are approximately 0.674 moles of Neon in 4.0 L of neon gas under the given conditions.
How many grams of CaBr2 would be needed to create 450. mL of a 2.00 M
solution? Round off your answer to the nearest gram. Record your answer in the
grid below.
Answer:
Mass of CaBr₂ = 179.9 g
Explanation:
Given data:
Volume of CaBr₂ solution = 450.0 mL (450/1000 = 0.45 L)
Molarity of solution = 2.00 M
Mass of CaBr₂ = ?
Solution:
Formula:
Molarity = number of moles / volume of solution in L
Now we will put the values.
2.00 M = number of moles / 0.45 L
Number of moles = 2 M × 0.45 L
Number of moles = 0.9 mol ( M = mol/L)
Mass of CaBr₂:
Mass of CaBr₂ = number of moles × molar mass
Mass of CaBr₂ = 0.9 mol × 199.89 g/mol
Mass of CaBr₂ = 179.9 g
To prepare 450 mL of a 2.00 M CaBr2 solution, one would need 180 grams of CaBr2, calculated using the molarity formula and the molar mass of CaBr2.
Explanation:To calculate the amount of CaBr2 needed to make a 2.00 M solution, we can use the formula: mass = molarity × volume × molar mass. The student wants a volume of 450 mL (0.450 L) of a 2.00 M CaBr2 solution. First, we need to find the molar mass of CaBr2 by adding the atomic masses of one calcium (Ca) atom and two bromine (Br) atoms. The atomic mass of Ca is approximately 40.08 g/mol, and the atomic mass of Br is approximately 79.90 g/mol. So, the molar mass of CaBr2 is 40.08 g/mol + (2 × 79.90 g/mol) = 199.88 g/mol.
Using the formula we have: mass = 2.00 M × 0.450 L × 199.88 g/mol = 179.892 g. Rounding off, we need 180 grams of CaBr2 to create 450 mL of a 2.00 M solution.
1. What is a physical change?
(10 Points)
O
A. A new substance is formed.
O
B. A substance is altered in size, shape or form.
O
C. Something has to break.
O
D. Something has to be folded.
What aboaieloben
Answer B
Explanation:
A Physical change is a change in one or more physical properties of matter without any change in chemical properties. For example physical change include changes in the size shape of matter.
How many grams of oxygen gas are there in a 2.3L tank at 7.5 atm and 24° C?
Answer:
22.656 grams of oxygen gas are there in a 2.3L tank at 7.5 atm and 24° C
Explanation:
An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law:
P * V = n * R * T
where R is the molar constant of the gases and n the number of moles.
In this case you know:
P= 7.5 atmV= 2.3 Ln= ?R= 0.082 [tex]\frac{atm*L}{mol*K}[/tex]T= 24 °C= 297 °K (being 0°C=273°K)Replacing:
[tex]7.5 atm* 2.3 L=n*0.082 \frac{atm*L}{mol*K} *297K[/tex]
Solving:
[tex]n=\frac{7.5 atm* 2.3 L}{0.082 \frac{atm*L}{mol*K} *297K}[/tex]
n=0.708 moles
Knowing that oxygen gas is a diatomic gas of molecular form O₂ and its mass is 32 g / mole, you can apply the following rule of three: if 1 mole contains 32 grams, 0.708 moles, how much mass will it have?
[tex]mass=\frac{0.708 moles*32 grams}{1mole}[/tex]
mass= 22.656 grams
22.656 grams of oxygen gas are there in a 2.3L tank at 7.5 atm and 24° C
Answer:
The mass of oxygen gas is 22.66 grams
Explanation:
Step 1: Data given
Volume of tank = 2.3 L
Pressure = 7.5 atm
Temperature = 24.0°C = 273 +24 = 297 K
Step 2: Calculate moles oxygen gas
p*V = n*R*T
⇒with p = the pressure of the oxygen gas = 7.5 atm
⇒with V = the volume of the tank : 2.3 L
⇒with n = the moles of oxygen gas = TO BE DETERMINED
⇒with R = the gas constant = 0.08206L*atm/mol*K
⇒with T = the temperature = 297 K
n = (p*V- / (R*T)
n = (7.5 atm * 2.3L) / (0.08206 L*atm/mol*L * 297K)
n = 0.708 moles
Step 3: Calculate mass of oxygen gas
Mass O2 = moles O2 = molar mass O2
Moles O2 = 0.708 moles * 32.0 g/mol
Moles O2 = 22.66 grams
The mass of oxygen gas is 22.66 grams
According to the law of conservation of momentum, which statement is true
about a system that has no external forces acting on it?
O
A. An increase in momentum before a collision must equal an
increase in momentum after the collision.
O
B. The sum of the momentums of all objects in the system is always
zero.
C. The total momentum of all objects in the system does not change.
D. The momentum of each object in the system remains the same
before and after a collision.
Answer:
D. The momentum of each object in the system remains the same
before and after a collision.
Explanation:
The law of conservation of momentum states that the momentum in a closed system does not change unless there is an outside force influencing the closed system.
Which term identifies a factor that will shift a chemical equilibrium?
Answer:
Temperature
Explanation:
Temperature is identified as a factor which will result in a shift in the chemical equilibrium.
What is Chemical equilibrium?This is defined as the point in which the concentrations of reactants and products remain constant with time.
Temperature could result in shifting the equilibrium to the left or right depending on factors such as nature of reactant etc.
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