Explanation:
All the alkali metals react vigorously with cold water. In each reaction, hydrogen gas is given off and the metal hydroxide is produced. The speed and violence of the reaction increases as you go down the group. This shows that the reactivity of the alkali metals increases as you go down Group 1.
Lithium
When lithium is added to water, lithium floats. It fizzes steadily and becomes smaller, until it eventually disappears.
lithium + water → lithium hydroxide + hydrogen
2Li(s) + 2H2O(l) → 2LiOH(aq) + H2(g)
Sodium
When sodium is added to water, the sodium melts to form a ball that moves around on the surface. It fizzes rapidly, and the hydrogen produced may burn with an orange flame before the sodium disappears.
sodium + water → sodium hydroxide + hydrogen
2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)
Potassium
When potassium is added to water, the metal melts and floats. It moves around very quickly on the surface of the water. The hydrogen ignites instantly. The metal is also set on fire, with sparks and a lilac flame. There is sometimes a small explosion at the end of the reaction.
potassium + water → potassium hydroxide + hydrogen
2K(s) + 2H2O(l) → 2KOH(aq) + H2(g)
Strong alkalis
The hydroxides formed in all of these reactions dissolve in water to form alkaline solutions. These solutions turn universal indicator purple, showing they are strongly alkaline. Strong alkalis are corrosive. Care must be taken when they are used - goggles and gloves should be worn.
Directions: Use the passage and the diagram below to answer the question. What is the average speed, in meters per second, of the trip across the field? (Write answer with all decimals but no units.)
Answer:
1.25m/s
Explanation:
Average speed = distance / time elapsed
= 100/80
=1.25m/s
How do the lungs help maintain the body's pH
balance?
Answer:by removing carbon dioxide from the body
Explanation:
I just got it right
What causes the movement of deep ocean currents?
Give two ways that vegetable oil is different from fat
Answer:
In simple terms, fats are animal fats whereas oils are vegetable oils. The other difference is fats tend to be solids at room temperature; on the other hand, oils tend to be liquid at room temperature.
Explanation:
can y’all help me with this plzz, thank you (:
Most likely B.
Because the mass of Cart B is higher than Cart A, its speed must be less than cart A's speed after the reaction. Therefore, options C and D are not applicable. Because of the ratio of masses between the carts, it would be safe to assume that A is not the answer. Although, I would still give option A a <2% chance of being the correct answer.
How has technology changed farming?
At what point on a roller coaster is the kinetic energy increasing?
1.At the bottom of the hill.
2.As it is going down the hill.
3.As it is climbing the hill.
4.At the top of the hill.
the wrong answer to just get points = banned
I will give brainliest
Answer:
2
Explanation:
How could the Cell Theory
have been developed sooner?
FREE BRAINLIEST! if you can answer this correctly ill give you brainliest and answer some of the questions you have posted :) thank you very much!!! (22pts)
Answer:
Its..... friction and normal force, have a good day AheadAnswer:
yo mama
Explanation:
A set of pulleys is used to lift a bookcase. 3000 J of work was done in 60 seconds. How much power was used?
Answer:
50 Watts
Explanation:
Power = work / time = 3000J / 60 seconds
Which of the following cannot be used to describe a longitudinal wave?
A.velocity
B.frequency
C.wavelength
D.crest
Answer:
crest
hope It helped you!
The term which cannot be used to describe a longitudinal wave is crest. Crests are formed in transverse waves. Longitudinal waves are composed of rarefactions and compressions.
What are longitudinal waves ?Unlike electromagnetic waves, mechanical waves only travels through a medium and through vacuum. There are two types of mechanical waves namely, longitudinal waves and transverse waves.
In transverse waves, oscillation of particles is in a direction opposite to the wave propagation. In longitudinal waves, oscillation is along the wave propagation.
Transverse waves are composed of crests and troughs. Whereas, longitudinal waves are composed of regions of low pressure and regions of high pressures that are, rarefactions and compressions respectively.
Therefore, option D does not describes a longitudinal wave.
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Select all the correct answers.
Which chemical reaction involving water is a decomposition reaction (breaking up) and which is a synthesis (building up)
reaction? If you're not sure, take a guess.
Water breaking down into hydrogen and oxygen is a synthesis reaction.
Water breaking down into hydrogen and oxygen is a decomposition reaction.
Hydrogen and oxygen combining to form water is a synthesis reaction.
Hydrogen and oxygen combining to form water is a decomposition reaction.
Answer:
Water breaking down into hydrogen and oxygen is a decomposition reaction
Hydrogen and oxygen combining to form water is a synthesis reaction
Explanation:
A decomposition reaction is a chemical reaction that involves the breakdown of a chemical reactant entity into two or more simpler product fragments
Water H₂O undergoes a decomposition reaction by breaking down into hydrogen, H₂,, and oxygen, O₂, as follows;
2H₂O (l) → 2H₂ (g) + O₂ (g)
A synthesis reaction is a reaction that involves the chemical combination of two or more dissimilar molecules or atoms to produce a different compound or molecule
Water, H₂O, is formed by a synthesis reaction of hydrogen, H₂,, and oxygen, O₂, combining as follows;
2H₂ + O₂ → 2H₂O
Samples of different materials, A and B, have the same mass, but the sample of A is higher in density. Which statement could explain why this is so?
A. The particles that make up material A have more mass than the particles that make up material B
B. The particles that make up material B have more mass than the particles that make up material A.
C. The particles that make up material B are more closely packed together than the particles that make up material A.
D. The sample of material A has greater volume than the sample of material B.
It's A
Answer: B. The particles that make up material B are more closely packed together than apart because that make up material A!!!
Answer:
C. The particles that make up material B are more closely packed together than the particles that make up material
Explanation:
I took the test, good luck! :)
3 kids are pushing on a cart 2 are pushing north at 50 N each. The 3rd is pushing South at -90 N. The net force is _N?
Answer:
Explanation:
When two forces act in the same direction , they add up and when they act in opposite direction , they subtract .
2 forces each of 50 N act in same direction , so they will add up to give resultant force of 100 N . Now third force acts in opposite direction so 100 N and - 90 N will subtract to give total resultant force .
Resultant force = 100 - ( - 90 ) = 190 N
So net force or resultant force = 190 N .
Use the information and table to answer the following question.
Scientists use either a melting or freezing point apparatus to determine the melting points of the following unknown compounds
as part of their investigation. Based on the melting points, the scientists determine the bond type and record the results in the
table as shown.
Unknown
Compound
Compound 1
Compound 2
Compound 3
Compound 4
772°C
17°C
Melting
Point
960°C
-56°C
Which statement correctly identifies the ionic compounds and why?
A Compounds 1 and 3 are lonic. Because Ionic compounds are composed of oppositely charged ions that are attracted to one
another, they require more energy to melt than covalent bonds.
OB. Compounds 2 and 4 are lonic. Because lonic compounds are composed of oppositely charged lons that are attracted to one
another, they require more energy to melt than covalent bonds.
OC. Compounds 2 and 4 are lonic. Because covalent compounds are composed of oppositely charged lons that are attracted to one
another, they require more energy to melt than lonic bonds.
OD Compounds 1 and 3 are lonic. Because covalent compounds are composed of oppositely charged ions that are attracted to one
another, they require more energy to melt than ionic bonds.
Answer: The answer is A
Explanation: I took that test already
Compounds 1 and 3 are ionic. Because Ionic compounds are composed of oppositely charged ions that are attracted to one another, they require more energy to melt than covalent bonds. Hence, option A is correct.
What is melting point ?Melting point of a substance is the temperature at which it converts from solid to liquid state. Melting point depends on the bond strength, molecular mass, temperature and pressure.
As the bond strength increases, the more energy have to be applied to weaken the intermolecular forces in solid to convert to liquid form. Ionic bonds are the strongest bond type. Thus, ionic compounds have highest melting point.
Therefore, the compounds 1 and 3 having highest melting point are ionic compounds. Remaining two with lower melting point are covalent. Therefore, option A is correct.
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A force of 800. N is for to push a car 40. m. How much work is done?
Answer:
32,000J
Explanation:
Workdone=Force x distance
=800 x 40
=32,000J
Write two complete sentences for each question for a total of four complete sentences. What is the purpose of cellular respiration? How is cellular respiration similar to photosynthesis?
PLEASE HELP ME
Explanation:
The purpose of cellular respiration is the to provide energy for the body of an organism. In this process, food materials are broken down by complex metabolic actions usually with the availability of oxygen. Then, energy is liberated for use by an organism and the waste is expelled.
Cellular respiration and photosynthesis are both similar. In that they are ways by which organisms obtain nutrition. The food for plant is derived by the process of photosynthesis. Also, other organisms use this food for their own nourishment.
PLEASE HELP I HAVE BEEN STUCK ON THIS FOR A WHILE.
A long platform is holding your physics teacher in the air above some hungry alligators. Your physics teacher has a mass of 75 kg and is located 2 m from one end. The 10.0 m platform has a mass of 10.0 kg, and its center of gravity is located 4.0 m from the same end. The platform is being held up by two students, one at either end.
a. What force is required by each student to hold the platform up?
Answer:
See Below.
Explanation:
I can't transpose the diagram onto Brainly. I'll do my best to describe what is going on.
Draw a horizontal line one inch from the each border of the page.To show what each of A and B are supporting, use an up arrow. Label the Ends A and B. B is on the right side.Put the physics teacher about 1.5 inches from B. His force goes down. Label it as 75 * 9.8 NewtonsPut the platform mass about 2.5 inches from BLabel it as 10 * 9.8 NewtonsB is the balance pointNow put in the distances. The lines are horizontalStudent A: 10 metersCenter of mass: 4 meters to BMass of Physics: 2 meters.Now you are ready to develop the equation
Clockwise
There is only 1 force where B is the Balance point that is going clockwise
10 * Force A
The AntiClockwise Moments
Platform: 4*10kg * 9.8 = 392 N m
Physics T: 2 * 75 * 9.8 = 1470 N m
So the Anti Clockwise moments = the clockwise moments.
10 * Force A = 392 NM + 1470NM Divide by 10. Remember that is in meters
Force A = 1862 N M / 10 10 M = 186 N
Does that make some sort of sense? It should Student A is the furthest distance from where all the action is at B. Therefore he is carrying the lightest weight.
Now what is the total force?
(75 + 10 ) * 9.8 = 85 * 9.8 = 833
This is one of those strange things that won't make sense until it does. Read the next sentence carefully. B is carrying most of the weight. Remember Newtons measure weight.
Support of A = 186 N
Support of B = x
Total of A+B = 933
186 + x = 833
x = 933 - 186
x = 647
So the forces are
A supports 186
B supports 647
which of the following is not an example of force? A. magnetism B. Electric force C. energy D. friction
Answer:
Friction
Explanation:
How is conduction shown here:
Conduction Transfers Thermal Energy Through Direct Contact
Answer:
Conduction is the transfer of heat between substances that are in direct contact with each other. ... Conduction occurs when a substance is heated, particles will gain more energy, and vibrate more. These molecules then bump into nearby particles and transfer some of their energy to them.
Explanation:
What is the drawback to use period of pendulum as time standard
The time period of a simple pendulum depends upon its length and value of'g'at any place. The period of the pendulum of fixed length
Accurate forecasts require careful study of the location, size, movement, and characteristics of large _____.
fronts
air masses
isobars
precipitation
Answer: B air masses
What are 3 characteristics of creative or "Literary" Nonfiction
Answer:
Creative nonfiction should (1) include accurate and well-researched information, (2) hold the interest of the reader, and (3) potentially blur the realms of fact and fiction in a pleasing, literary style (while remaining grounded in fact).
I hope it's helpful!
PLEASE HELP ASAP!!!!!!!!!!!!!!!!!!
Answer:
The answer is A) byee!!
Explanation:
why do you think festival dances should be introduced to the younger generations of today
Answer:
Festival dances should be introduced to the younger generations of today because they teach them about different cultures. Festival dances are also a way to be active and have a fun time.
Explanation:
If a 2 kg ball is moving at 6 m/s to the right and then hits a wall and bounces back at - 4 m/s (left), what is the change in momentum (in kg*m/s)?
Answer:
The change in momentum (in kg*m/s) [tex]= 20[/tex]
Explanation:
The change in momentum is equal to
Final Momentum - Initial Momentum
As we know
Momentum is equal to the product of mass and velocity
M = m * v
Thus, change in momentum
[tex]m_2v_2 - m_1v_1[/tex]
here m1 = m2 = 2 Kg
Substituting the given values in above equation we get -
[tex]2 * 6 -( 2 *-4)\\12 + 8 = 20[/tex]kg m/s
50 POINTS!! BRAINLEST
Answer:2 one
Explanation:
Answer:
A webpage that is green has a title in red font to create emphasis. What color scheme is this?A webpage that is green has a title in red font to create emphasis. What color scheme is this?A webpage that is green has a title in red font to create emphasis. What color scheme is this?:
Blood vessels that have valves in them:
Answer:
veins
Explanation:
veins are the blood vessels which have valves to prevent backwardflow of blood .
plz mark my answer as brainlist plzzzz vote me also hope this will be helpful to you
All materials are made up of elements. Which of the following best describes elements? A. Mixtures combine in several different ways to make many kinds of elements. B. Elements are unable to combine in order to make different compounds. Elements combine in several different ways to make many kinds of compounds. > D. Compounds combine in several different ways to make a limited number of elements,
Answer:
a.
Explanation:
Answer:
I am pretty sure it is C!
Explanation:
According to www.open.edu,
Elements are substances that are made from one type of atom.
Compounds are substances made from atoms of different elements joined by chemical bonds.
A mixture is made by simply mixing together elements and compounds.
Atoms are the basic building blocks.
i think A is incorrect because, while the statement may be correct, it is talking about Mixtures, not elements themselves!
B is incorrect because elements ARE able to combine to form compounds!
D is incorrect because ELEMENTS combine to create compounds, i am pretty sure compounds don't combine to create elements.
If there are 20 volts across a 4 ohms resistor, what is the current?
a) 10 A b) 80 A
c) 20 A d) 5 A
If there are 20 volts across a 4 ohm resistor, then the current is 5A (20/4), which is present in option D, as the current can be measured by Ohm's law and more current means less resistance and less current means there is more resistance.
What is the significance of Ohm's law?It is significant for the understanding of the current and related fields, it can be used to predict the behavior of electrical circuits, it is helpful to design circuits, it gives knowledge of energy efficiency in electrical systems, and it helps in understanding the relationship between voltage, current, and resistance in a circuit.
Hence, if there are 20 volts across a 4 ohm resistor, then the current is 5A (20/4), which is present in option D, as the current can be measured by Ohm's law and more current means less resistance and less current means there is more resistance.
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