Pls help i'll mark you the brainlest What force is needed to make ball fall on Earth if it has a mass of 13kg

Answer:

Explanation:

How many cm of a solution of 0.100 mol dm NaOH are required to completely  neutralize  25.0 cm of 0.250 mol dm H3PO4?.

a) Write a balanced equation for the reaction NaOH to neutralize (4 marks

?. ) 25.0 cm of 0.250 mol dm H3PO4

H3PO4 + 3NaOH----------> Na3PO4 +3 H2O

b) How many moles of H3PO4 need to be neutralized? (1 marks)

25.0 cm3 of 0.250 mol dm3 H3PO4: 1 liter has 0.25 moles. 100 ml has 0.025 moles 25 ml has o.025/4 molea or 0.00625 moles)

c How many moles of NaOH are needed to neutralize the H3PO4? (1 marks)

for every moles of H3PO4, WE NEED 3 MOLES OF NaOH.  FOR 0.00625 MOLES WE NEED 3X 0.00625 =0.01875 MOLES OF NaOH

d) How many cm3 of 0.100 mol /l NaOH contain the moles in question 5(©) above? (1 marks)

1 L CONTAINS 0.100 Moles

100 ml contains 0.010Moles

we need 187.5 ml since (187.5 X 0.100)/1000=0.01875

Answer:

Selenium

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Explanation:

if u ask which group

so it is halogen

or u ask which type of matter

then liquid

We have that  the time that will have elapsed when 25.00 grams remains is

T=72hours

From the question we are told

100.0 grams of an isotope with a half-life of 36.0 hours is present at time zero. How much time will have elapsed when 25.00 grams remains?

Generally the equation for the Half life  is mathematically given as

Where

[tex]X=\frac{25}{100}\\\\X=0.25\\\\Therefore\\\\\frac{1}{2}^n=0.25\\\\n=2 half lives[/tex]

Therefore

T=2*36

T=72 hours

Hence

 the time that will have elapsed when 25.00 grams remains is

T=72hours

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Answer:

2 atoms

Explanation:

Answer:

1

Explanation:

Any digit that is not 0 is always significant

Answer: Iron

Explanation: does not react with water, but hydrochloric acid will dissolve them, displacing the hydrogen from the HCl. Iron reacts with hydrogen chloride to produce iron chloride, FeCl2 — sometimes known as ferrous chloride.

To solve such this we must know the concept of chemical reaction. Iron is the metal, which dissolves in hydrochloric acid to produce hydrogen gas, but does not react with steam.

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

When metals react with acid the liberation of hydrogen gas take place.  Metal which is at top of reactivity series react with both acid and steam or liquid water. Iron is the only metals which dissolves in hydrochloric acid to produce hydrogen gas, but does not react with steam or liquid water.

Therefore, iron is the metal, which dissolves in hydrochloric acid to produce hydrogen gas, but does not react with steam.

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Answer:

20 g g/mL. 15.77

Explanation:

i think i answer it

Answer:

remain at rest

Explanation:

Answer:

Determine the mass of substance and it's molar mass. Divide the given mass by it's molar mass to get moles and multiply time

6.002*1023 molecules 1mole

Answer:

c. because all countries around the equator experiences heat

Answer:

0.51

Explanation:

i got it wrong multiple times just for this to be the answer.

listening to mitski while crying over this science goodluck

Answer:

I believe that it is a

Explanation:

I can't comment on you the other question for some reason. Do you have any other means of communication??

Answer:

A

Explanation:

Answer:

It's the first one I think "it absorbs the other greenhouse gases and becomes more potent

Nitrogen is one of the major elements that are cycled in nature. The major sink for nitrogen in nature is the atmosphere.

Biogeochemical cycles in nature show the diverse ways that elements move through the various spheres on earth.

Nitrogen is trapped from the atmosphere by nitrogen- fixing bacteria that live in the root noodles of leguminous plants which convert atmospheric nitrogen to nitrates. This nitrogen is transferred to living organisms when they eat those plants and become incorporated into biomass.

Decomposition returns this nitrogen in biomass to the soil. The action of denitrifying bacteria converts nitrates in soil back to atmospheric nitrogen. Also several anthropogenic sources release nitrogen into the atmosphere as NOx.

The atmosphere consists of 78% nitrogen hence it serves as the largest sink for nitrogen in nature.

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Answer:

Halogens are highly reactive

Answer:

law of independent assortment

Answer:

Elements of the periodic table are arranged in order of increasing atomic number. the periodic law states "when elements are arranged in increasing atomic number, there is a periodic repetition of their  chemical and physical properties."

Explanation:

Answer:

yeah think that’s correct

Explanation:

not exactly sure how to explain this, I just know that it’ll prolly just stay the same and not move to any high and low regions of the cell

Answer:

No. Two atoms of the same chemical element are typically not identical. Since the states of the electrons in an atom are what determine the nature of the chemical bonding that the atom experiences, two atoms of the same element can react differently if they are in different states.

Answer: No

Explanation: Two atoms of the same chemical element are typically not identical. First of all, there is a range of possible states that the electrons of an atom can occupy. Two atoms of the same element can be different if their electrons are in different states.

Answer:

exposure to the sun (heat and light) for long period of time and air (oxygen reacts with particles)

Answer:

a

Explanation:

The object with greater mass is having greater kinetic energy. Here, all the objects has the same velocity therefore, the bicycle is having least kinetic energy.

Kinetic energy is a form of energy generated by virtue of the motion of the object. The kinetic energy is related to the mass and velocity of the body by the expression below:

KE = 1/2 mv².

As per this equation, kinetic energy increases with an increase in mass or/ and velocity. The substance with greater mass is possessing the greater kinetic energy.

A dump truck has greater mass than a car and bicycle. Thus, at the same velocity for all, the greater kinetic energy is for the truck and the least kinetic energy is for the bicycle having the least mass here. Thus, option A is true.

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Answer:

A transition from one accepted theory to another or from one employed method to another.

Explanation: