According to Newton’s Third Law, if someone jumps off a skateboard, the skateboard will roll backwards because -

Answer:

With the cooler water at the bottom, this uneven temperature distribution creates convection currents that accelerate the cooling process. Even with more ground to cover to freeze, the temperature of the hotter water can drop at a faster rate than the cooler water.

Explanation:

Bronsted - Lowry base can accept a hydrogen ion and can produce hydronium.

Bases have the pH value in between the range of 7 to 14.

According to the Bronsted - Lowry theory of acid & base, those substance which produces H⁺ ion or proton in the aqueous medium are known as acids and those substance which accepts the H⁺ ion or proton in the aqueous medium are bases. Water is also behave as Bronsted - Lowry base as it accepts the H⁺ ion and forms hydronium ion H₃O⁺.

Hence, option (b) & (c) are correct, i.e. They can accept a hydrogen ion and produce hydronium.

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Answer:

Well first, a scientific claim is claims or statements after experimenting. Similar to other claims but they have evidence and data to support the claim.

So we would show demonstrations because we need support our scientific claim.

Answer:

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Explanation:

A force is an agent that causes a change in the shape or state of motion of an object.

Forces such as gravity, helps keep objects on earth's surface.

A force is a pull or push agent which causes a change in the shape or motion of a body.

Forces may or may not result in motion.

Forces can change the position, shape and movement of an object but not its color.

Types of forces include:

Friction is a force that slows or stops the motion of an object.

Magnetism is a force is that attracts objects mad of steel, nickel, or cobalt.

Gravity is a force that pulls objects to the centre of the earth.

Example of a pushing force is pushing a car.

Example of pulling force is closing a car door.

Due to the gravitational force acting on all bodies on the earth surface, we do not fall off the earth.

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Answer:

The transition elements have their valence electrons in two different sets of orbitals that are (n-1)d and ns. Thus, transition elements show variable valencies due to the involvement of penultimate d shell electrons.

Explanation:

Answer:

the solvent =water+coffee powder

the solute =sugar

Explanation:

Breaking up, crushing or grinding a sugar cube before adding it to water increases the sugar's surface area. The more surface area a solute has, the faster it will dissolve because more particles of the sugar can interact with the water. This means the finer the sugar particles meaning a larger surface area which leads to an increase in a faster reaction

it cannot be passed to the next generation meaning A chromosome will be eliminated

Answer: Each element is given its own chemical symbol, like H for hydrogen or O for oxygen. Chemical symbols are usually one or two letters long.

Explanation:Every chemical symbol starts with a capital letter, with the second letter written in lowercase. For example, Mg is the correct symbol for magnesium.

-2.5089 kJ is the amount of heat is released by the combustion of the naphthalene.

Released amount of heat is calculated by using the below formula:

Q = -mcΔT, where

m = mass of naphthalene = 0.25g

c = specific heat of calorimeter = 4.13 kJ/°C

ΔT = change in temperature = 26.43°C - 24°C = 2.43°C

Putting all these values in the above equation, we get

Q = - (0.25 × 4.13 × 2.43) = - 2.5089 kJ

Hence, - 2.5089 kJ heat is released.

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Answer:

It's A

Explanation:

I took the test. For A p e x

The formula unit of compound made up from Pb4+ and oxygen is PbO2.

The formula unit for a compound made from Pb⁴⁺ and oxygen is PbO₂. Therefore, option (1) is correct.

A formula unit represents the lowest whole number ratio of ions in an ionic compound. The formula mass of a substance is the sum of the atomic masses of the ions present in the formula unit of an ionic compound.

Formula unit is the empirical formula of any covalent or ionic solid compound which is used as an independent entity for stoichiometric calculations. Formula mass is also defined as the sum of atomic masses of constituent atoms in an ionic compound.

A molecule is made up of two or more elements that are covalently bonded. Also, the molecular mass gives the mass of a molecule relative to that of a carbon twelve atom which has a mass of twelve units.

As we know the valency of lead is 4 and the valency of oxygen is 2. To satisfy the valency of each other two oxygen combine with one lead (IV). Therefore, the formula unit of the compound is PbO₂.

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Answer: D. A chemical reaction releases thermal energy.

Explanation:  

Hope this helps! <3 :)

form calcium hydroxide and hydrogen gas

Ca + 2H₂O ⇒ Ca(OH)₂ +H₂

Answer:

When the water droplets in the cloud get too heavy they will fall. Which causes rain to fall. Gravity force pulling the droplets toward the Earth's surface.

It pulls precipitation down form could and pulls water downhill. Gravity pulls denser air and water downwards, forcing less dance air and water to move upwards.

Answer:

B. The forces holding atoms together are stronger in a liquid than in

a gas

I hope that this helps!

With a container at 1.30 atm and 224 K is heated to 815k, the new

the pressure of the gas is mathematically given as

P=4.7299atm

Question Parameter(s):

A sample of gas in a rigid container at 1.30 atm and 224 K is heated to 815

K.

Generally, the equation for the Ideal gas  is mathematically given as

P1/T1=P2/T2

Therefore

1.30/224=P2/815

P=4.7299

In conclusion,  new the pressure

P=4.7299atm

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Answer:

Solid

Explanation:

Gas and liquids cant have definite shape which should be crossed off after you read shape because gas goes everywhere and liquids are too runny

Reactant concentration, the physical state of the reactants, surface area, temperature, and the presence of a catalyst are the four factors to influence the rate of a homogeneous reaction.

The term rate of reaction is defined as the speed at which a chemical reaction takes place. It is also defined as proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit time.

Surface area, greater surface area, more collisions are available and then concentration, when increase the concentration then increase the likelihood of reactants colliding. Catalysts increase reaction without itself getting used up.

Thus, The factors to influence the rate of a homogeneous reaction are Reactant concentration, the physical state of the reactants, surface area, temperature, and the presence of a catalyst.

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Answer:

Blue

Explanation:

Blue would have the longest wave length because following ROY G BIV the wave length distance between the two decreases as you move from Red to Violet.

Answer:

The adjustable legs and the table of sand.

Note:The question is incomplete. The complete question is given below.

Using Models to Answer Questions About Systems

Armando’s class was looking at images of rivers formed by flowing water. Most of the rivers were wide and shallow, but one river was narrow and deep. Armando’s class thinks that this river is narrow and deep because:

Armando designed the model below to try to answer the question: Why is this river so narrow and deep?

Explanation:

The model designed by Armando will be helpful to answer the question because of the following features it possesses:

1. An adjustable leg- since one of the hypotheses put forward by the class to explain why the river was narrow and deep was that the hill that the water flowed down was very steep, the adjustable legs can be lowered or raised in order to make the slope shallower or steeper so that their hypothesis can be tested.

2. A table of sand- the table of sand serves as the streambed. By adjusting the size of the sand grains to be larger or smaller, the students will be able to to test their second hypothesis that the small size sand grains that the water flowed through was the reason for the river to be narrow and deep.

The results of their experiments will enable them to come to a conclusion.

Answer:

The direction of flight depends on the wind, but the altitude of the balloon can be controlled by changing the temperature of the air inside the envelope. the pilot controls the ascent of the balloon.

Explanation:

:)

London’s "killer fog" or The Great Smog of London was the extreme event of air pollution in London. Millions of coal fires and stagnant air were the prime reason for the event.

The Great Smog of London was one of the worst events of the air pollution that engulfed the city of England. The industrial air pollutants of the burning coal and high-pressure weather circumstances made the city covered in smog.

This event caused many deaths due to pneumonia and bronchitis in people.  The burning of the coal in the industrial plants of the city was the major reason for the smog.

Therefore, option B. millions of coal fires and stagnant air were the main reason for the great smog of London.

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Answer:

in 1983, Lake Mead had a recorded water level of 1,225 feet above sea level. The closest it's been to that level in modern times was in 2000. Explanation: