Answer:
If the star has smaller mass than the Sun, it can fuse hydrogen into helium for at least a trillion years. The larger a star, the shorter its life because it fuses hydrogen into helium much more quickly. A star whose mass is more than 20 Suns will run out of hydrogen in only a few hundred million years.
A student performed an experiment in which 10 mL of a strong acid was placed on a sample of limestone. Bubbles formed where the acid touched the limestone. After 20 minutes, the bubbling stopped and the surface of the limestone appeared unchanged. What is an observation that suggests a chemical reaction did in fact take place between the acid and the limestone?
a) The limestone appeared to be unchanged.
b) The acid had to be prepared beforehand.
c) Bubbles formed where the acid and limestone touched.
d) None of the above
Answer:
Answer is D, None of the above :)
Explanation:
Iodine shines like metals but is not metal what is its basis
Answer:
Iodine is a non-metal, but it is lustrous (lustrous is the property of metal) in nature.
Which of these affects the motion of an object
A. the position of nearby objects
B. the force acting on the object
C the object's length
D. the age of the object
Answer:
B
Explanation:
If an object is acted upon by another force this will cause it to change the direction and velocity of where it is going.
Use the drop-down menus to match the name and structure for the following cycloalkanes. A five-sided polygon. A square. A five-sided polygon with one line extending from a point. A 6-sided polygon with a line extending from one point to a C H 3.
Answer:
A five-sided polygon.- cyclopentane
A square.- cyclobutane
A five-sided polygon with one line extending from a point.- methylcyclopentane
A 6-sided polygon with a line extending from one point to a C H 3.- methlcyclohexane
Explanation:
The correct options are :
The 5 sided polygon is cyclopentane.The square is a cyclobutane.The 5 sided polygon extends from a point.- methyl cyclopentane.The six-sided polygon CH3 is methylcyclohexane.What are cycloalkanes?Cycloalkane is a cyclic hydrocarbon meaning that the carbon of the molecules is arranged in the form of a ring. These are also saturated and all of the carbon stems make up a ring.
These are monocyclic and made from hydrogen and carbon. One ring structure is named after cyclo. Cyclobutane is columns gases and is available in liquefied gas.
Find out more information about the cycloalkanes.
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It’s due in 3 minutes please help
Answer:
The Answer is gonna be Indroduction of non-native plant species
How can flame color identify an unknown metal?
How can a spectrum positively identify an element?
How can astronomers tell which elements a star contains without a sample of it?
Both propanoic acid and propanone are soluble in water. Please draw a diagram and explain which compound is more soluble.
Answer:
Explanation:
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Is anyone good at chemistry if so can someone help me please ?
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Question 15
We're given the [OH⁻] as 8.34 × 10⁻¹² M. Using the formula pOH = -log[OH⁻], the pOH of this solution would be -log(8.34 × 10⁻¹²) ≈ 11.08.
The pOH is, for lack of a better term, the "opposite" of pH: A pOH of 7 is neutral; a pOH less than 7 is basic; and a pOH greater than 7 is acidic.
This follows from the relation, pH + pOH = 14. In this case, with a pOH of 11.08, our pH would be 14 - 11.08 = 2.92, which is acidic (pH < 7).
Thus, the correct answer choice is B.
Joaquin's doctor tested Joaquin's reflexes by tapping his knee. The doctor
explained to Joaquin that the tapping sends a signal to his spinal cord. The
spinal cord then sends a signal to the muscle in Joaquin's thigh, and his leg
moves. Which of the following body systems is involved in this process?
A. Respiratory system
B. Nervous system
C. Skeletal system
D. Digestive system
Answer: Skeletal System
Explanation: Sense It's Sending up a signal up Joaquin's spinel cord It must be traveling threw his skeletal system
Answer:
its the nervous system because by tapping the knee, it will send a nerve down the neuron, through the mylein sheath and through the axon terminals to the receptors, which will recieve the nerve's signal and send it to the brain through the spinal cord in simple terms.
7. Which of the following is a proof that light travels in a straight line?
A. Formation of clouds
C. Formation of rainbows
B. Formation of colors
D. Formation of shadow
Answer:
formation of shadow is right
Answer:
correct answer is D
Explanation:
When you see a shadow, it is directly behind the object.
Which type of substances do you separate into ions when writing the complete ionic equation?
a. Aqueous
b. Liquid
c. Gas
d. Solid
Answer:
a. Aqueous
Explanation:
Took the test
A science teacher is planning a science lab in which students will identify conditions that do and do not speed up the time required for
sugar to dissolve in water. Which of the following conditions will NOT have an effect on the dissolving time?
B. stirring the water
D. magnetizing the sugar
E grinding the sugar
of heating the water
Answer: E
Explanation:
23. Forces accelerate objects. Newton's second law state that force equals ______times?
Answer:
F = ma, or force is equal to mass times acceleration.
I need help
Balance the chemical equation
Answer:
Iwill add 2 for Na and 2 for NaCl so the answer is "C"
3.
The color of the powdered form of a mineral is called
O fracture
O cleavage
O luster
O streak
Answer:
D. Streak.
Explanation:
A mineral, in simple terms, can be defined as a solid inorganic substance that occurs in a pure form with a specific crystal structure. A mineral is identified based on its physical properties which include luster, color, streak, crystal shape, etc.
The color of the powdered form of a mineral is called a streak. A streak is a useful property in distinguishing sulfide and oxide minerals. To check the color of a mineral, it is rubbed against the surface of a ceramic streak plate or a piece of unglazed ceramic. In its finely powdered form, a mineral is easy to identify.
Therefore, option D is correct.
When naming bases, you add ___ to the end
Answer:
hydroxide ion
Explanation:
because base produce hydroxide ion when dissolved in water
4. The following occurs when heat energy is removed: Gas --A-> Liquid-B--> Solid.
What would be the phase change for A and B respectively?
A. Condensation, freezing
C. Condensation, melting
B. Melting, evaporation
D. Sublimation, deposition
Answer: The phase change for A and B respectively is condensation, freezing.
Explanation:
A process in which gaseous state of a substance converts into liquid state is called condensation.
For example, conversion of steam into water.
A process in which liquid state of a substance converts into solid state is called freezing.
For example, conversion of liquid water into ice.
Thus, we can conclude that the phase change for A and B respectively is condensation and freezing.
Condensation and freezing would be the phase change for A and B respectively.
What is Freezing?This is the process in which a liquid becomes solid and is mostly caused by exposure to cool temperatures.
Gaseous substances also have the ability to become liquids through the process known as Condensation. This therefore makes option A the most appropriate choice.
Read more about States of matter here https://brainly.com/question/9402776
List 3 technologies that have made jobs easier.
Answer:
-security hardware
- artificial intelligence
wifi, internet, phones, voice assistants, drones.
would you rather eat pizza the rest of your life, or cake?
Answer:
cake
Explanation:
now here me out, no cake is specified so i can say i want a cake that has pizza on it, take off the pizza, and eat it, this goes with any other food without me having to eat the cake
if energy cannot be created then how did it exist in the first place???
Answer:
Different types of generators are used to create energy. Electrical energy is caused by moving electric charges called electrons. Electricity is a type of energy that comes from electrical energy. ... In power stations, turbines are turned using energy from sources such as heat, wind and moving water.
Explanation:
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In which way do buffalos protect themselves from predator animals such as lions
Answer: Both males and females have sharp, curved horns extending from the sides of their heads which are used to defend themselves against predators.
Explanation:
An electron confined in a one-dimensional box is observed, at different times, to have energies of 12 eV, 27 eV, and 48 eV. What is the length of the box? 45. | The nucleus of a typical atom
Answer:
[tex]l=3.5*10^{-10}m[/tex]
Explanation:
From the question we are told that:
1st Energy [tex]E_1=12eV=4(3eV)[/tex]
2nd Energy [tex]E_2=27eV=9(3eV)[/tex]
3rd Energy [tex]E_3=48eV=16(3eV)[/tex]
Generally the equation for Energy E for electron in one dimensional box at ground state [tex]E_0[/tex] is mathematically given by
[tex]E_0=\frac{h}{8ml^2}[/tex]
[tex]E_0=\frac{h}{8ml^2}[/tex]
Therefore Length a is mathematically given as
[tex]l=\sqrt{\frac{h^2}{8mE_0} }[/tex]
[tex]l=\sqrt{\frac{(6.625*10^{-34})^2}{8(9.1*19^{-31}{(3eV(1.6*10^{-19}))}}[/tex]
[tex]l=3.5*10^{-10}m[/tex]
Which do you use to qualify matter?
A. Thermometer
B. Five senses
C. Balance
D. Tape measure
Answer:
c balance
Explanation:
if you weigh something, you prove it's there.
2) A balloon was inflated to a volume of 5.0 liters at a temperature of
7.0°C. It landed in an oven and was heated to 147°C. What is its new
volume?
Answer:
6.12 L
Explanation:
Given that,
Initial volume, V₁ = 5 L
Initial temperature, T₁ = 7.0°C = 343 K
Final temperature, T₂ = 147°C = 420 K
We need to find its new volume. The relation between volume and temperature is given by :
[tex]\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}\\\\V_2=\dfrac{V_1T_2}{T_1}\\\\V_2=\dfrac{5\times 420}{343}\\\\V_2=6.12\ L[/tex]
So, the new volume is 6.12 L.
What is the force being applied to an object with a mass of 12 KG and an acceleration of 4M/S
Answer:
48 newtons
Explanation:
A rigid, insulated vessel is divided into two compartments connected by a valve. Initially, one compartment, occupying one-third of the total volume, contains air at 500oR, and the other is evacuated. The valve is opened and the air is allowed to fill the entire volume. Assuming the ideal gas model with variable specific heats. Determine: a. the final temperature of the air (in oR) b. the amount of specific entropy produced (in Btu/lbm oR)
Answer:
a) the final temperature of the air is 500° R
b) the amount of specific entropy produced is 0.0758 Btu/lb-°R
Explanation:
Given the data in the question;
Air at 500° R = [tex]T_i[/tex]
Using first law of thermodynamic;
δQ = dU + W
now, since the vessel is insulated, the transfer is zero, work done also is zero since there is also no external work done.
δQ = dU + W
0 = dU + 0
dU = 0
[tex]u_f[/tex] - [tex]u_i[/tex] = 0
[tex]u_f[/tex] = [tex]u_i[/tex]
hence, change in internal energy is 0
Now, since the ideal internal energy is a function of temperature, the temperature will also remain the same;
[tex]T_f = T_i[/tex]
F = 500° R
Therefore, the final temperature of the air is 500° R
b)
given that; initial volume is one-third of the total volume
V₁ = [tex]\frac{1}{3}[/tex]V₂
3V₁ = V₂
3 = V₂/V₁
Now, we take the value of gas constant R from air property table; gas constant R = 0.069 Btu/lb-R
so we calculate the entropy change;
Δs = [tex]c_v[/tex]In( [tex]\frac{T_2}{T_1}[/tex] ) + R.In( [tex]\frac{V_2}{V_1}[/tex] )
we substitute
Δs = [tex]c_v[/tex]In( [tex]\frac{500}{500}[/tex] ) + 0.069 × In( 3 )
Δs = 0 + [0.069 × In( 3 )]
Δs = 0 + [0.069 × 1.0986]
Δs = 0.0758 Btu/lb-°R
Therefore, the amount of specific entropy produced is 0.0758 Btu/lb-°R
Insulated vessels separate the environment of the outer and the inner system. The final temperature is 500 degrees R and 0.0758 Btu/lb- degree R is the entropy.
What is temperature?The temperature is the measure of the hot or the coldness of the system. The first law of the thermodynamics is used to measure the final temperature of the system:
[tex]\rm \Delta Q = \rm \Delta U + W[/tex]
The work done will be zero as the system is insulated and no external work is being done.
[tex]\begin{aligned} \rm 0 &= \rm \Delta U + 0\\\\\rm U_{f} - U_{i} &= 0\\\\\rm U_{f} &= \rm U_{i} \end{aligned}[/tex]
Hence, the change in the internal energy is zero. Thus, the final temperature will remain the same,
[tex]\rm T_{f} = \rm T_{i} = 500 ^{\circ} \rm R[/tex]
Now, as we know, the initial volume is one-third of the total volume then,
[tex]\begin{aligned} \rm V_{1} &= \rm \dfrac{1}{3} V_{2}\\\\\rm 3V_{1}&= \rm V_{2}\\\\3 &= \rm \dfrac{V_{1}}{V_{2}}\end{aligned}[/tex]
The change in entropy is calculated as:
[tex]\begin{aligned} \rm \Delta S &= \rm C_{v} ln ( \dfrac{T_{2}}{T_{1}}) + R \times ln ( \dfrac{V_{2}}{V_{1}}) \\\\&= 0 + [0.069 \times \rm ln( 3 )]\\\\& = 0.0758 \;\rm Btu/lb-^{\circ}R \end{aligned}[/tex]
Therefore, the entropy produced is 0.0758 Btu/lb- degree R.
Learn more about entropy here:
https://brainly.com/question/19538748
Name (3) ways an animal can use energy from food?
Answer:
The food chain begins with the sun: plants get their energy by photosynthesizing sunlight into energy, and then herbivores eat those plants to get their energy. Carnivores who then eat the herbivores are getting that sunlight passed along from sun to plant to herbivore to carnivore.
A coffee cup calorimeter will not be used to
directly measure the enthalpy of magnesium
combustion because
✓ the coffee cups could melt.
The calorimeter is made of coffee cups instead of
a beaker because coffee cups are
✓ better insulators
than beakers.
You will not measure the enthalpy of the reaction
of
✓ H2 and 02
in the coffee cup calorimeter because this reaction involves gases
Instead, you will use a well-known published
value.
These are the correct answers on edge 2021
Answer:
Ingles porfavor
Explanation:
The calorimeter is used to measure the heat of the system. The enthalpy of the combustion of magnesium cannot be measured by the calorimeter as it could melt the cup.
What is a coffee cup calorimeter?A coffee cup calorimeter is a styrofoam cup that contains partially filled water and is dipped with a thermometer. The reaction occurs in the water of the cup and hence differs from the bomb calorimeter.
The enthalpy of combustion is rigorous which can dissolve the polystyrene cup and hence is not used. They are better insulators than a beaker. The coffee cup calorimeter is not used to measure the enthalpy of hydrogen and oxygen as they involve gases that can escape the cup.
Learn more about coffee cup calorimeter here:
https://brainly.com/question/4390364
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how many moles are there in 2.20 x 10^23 molecules of Na2SO4
Answer:
Explanation:
450 grams of Na2SO4? 450 Na soullnol Na2SO4 16.02x1023 molec, Na₂SO4 = 119x1024. | 142.05g Na25041 Imol Naz