Science pls help me having trouble on the third one

Answer:

3. 95%

Explanation:

Invertebrates make up over 95 percent of the Earth's animal species. For many years, invertebrates have been kept as pets, displayed in aquariums and zoos, used for research, and consumed.

Answer:

95% i took the test

Explanation:

Answer:

Determine the final temperature when a 25.0 g piece of iron at 85.0 °C is placed into 75.0 grams of water at 20.0 °C.

First some discussion, then the solution. Forgive me if the points seem obvious:

a) The colder water will warm up (heat energy "flows" in to it). The warmer metal will cool down (heat energy "flows" out of it).

b) The whole mixture will wind up at the SAME temperature. This is very, very important.

c) The energy which "flowed" out (of the warmer water) equals the energy which "flowed" in (to the colder water)

Explanation:

Answer:

How is an environment able to support different varieties of organisms? ... It provides all the necessary conditions, such as temperature, space, water and food resources, oxygen and carbon dioxide, that suit the needs of the organisms. Examples of habitat include forests, mountains, bodies of water, and even puddles.

Explanation:

Answer:

32 degrees

Explanation:

Answer: It’s Lower

What can you say about the pH of a carbonic acid solution compared to that of a sulfuric acid soloution with the same contention: Strong acids dissociate fully in water to produce the maximum number of [tex]H^{+}[/tex]ions. The pH levels of strong acids are smaller than those of low acids, which is why the reactions rates for strong acids are greater than the reactions of weak acids with products like metals, metal carbonates, etc. Meaning The pH Level is lower.

Answer:

C. Atoms are arranged during chemical reactions

Explanation:

All matter is made of atoms and atoms are indivisible and indestructible. compounds are formed by a combination of two or more different kinds of atoms.

Answer:

D

Explanation:

Atoms make up all matter on earth, basically atoms make up everything, even air.

They mimicked the flight of birds.

Answer:

B.

Explanation:

Just took the test

Answer:

That leaves us with: 1s2 2s2 2p6 And that is the electron configuration for F- , the Fluoride ion.

Explanation:

plz give brainliest

Answer:

Cat

Explanation:

Bcuz I said so that it's a cat

Explanation:

i think the answer is....b

The diagram that represents single replacement reaction is:

b.

This reaction is also known as displacement reaction. It is a reaction in which one element is substituted for another element in a compound. When a replacement reaction occurs, a new aqueous compound and a different pure element will be generated as products. For example:

[tex]2HCl(aq)+Zn(s)--->ZnCl_2(aq)+H_2(g)[/tex]

Thus, option b is correct.

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Answer:

i dont know

Explanation:

Answer:

Cu2+(aq) + 2OH-(aq) => Cu(OH)2(s)

Explanation:

Use of aqueous sodium hydroxide is a precipitation reaction to test for anions or cations. Aqueous sodium hydroxide in a precipitate test forms a insoluble precipitates along with some colors characteristics.

Aqueous sodium hydroxide (NaOH) when mixed with copper(II) (Cu2+) forms a blue precipitate. The formula is as follows:

Cu2+(aq) + 2OH-(aq) => Cu(OH)2(s)

Answer:

Answer: If the atom loses 2 electrons, the net charge on the atom will be 2+

If the atom gains 4 electrons, the net charge on the atom will be 4-

Explanation:

An atom is smallest unit of a matter or substance.It consist of three subatomic particles : electrons, protons, neutrons.

Protons are positively charged, neutrons are neutral and both are located in nucleus where mass of an atom is concentrated.

Electrons are negatively charged and are located outside the nucleus where they orbit in different energy levels around the nucleus.

In an atom, when electrons are lost, the atom gains a positive charge and forms cation. In an atom, when electrons are gained, the atom occupies a negative charge and forms anion.

Thus an atom with 9 electrons and 9 protons will be electrically neutral.

On losing 2 electrons, there will be 7 electrons and 9 protons will have 2+ charge.On gaining 4 electrons, there will be 13 electrons and 9 protons will have 4- charge.

Answer:

The metals are to the left of the line (except for hydrogen, which is a nonmetal), the nonmetals are to the right of the line, and the elements immediately adjacent to the line are the metalloids.

Answer:

Birds evolved from a group of meat-eating dinosaurs called theropods. That's the same group that Tyrannosaurus rex belonged to, although birds evolved from small theropods, not huge ones like T. rex.

Answer:

we haven't done anything to study the roots of the bird yet

Answer:

Crystals that grow more slowly, tend to be larger. For crystals that were grown by slow cooling of the solvent: it usually improves the quality and size of the crystals, if the solution is slowly warmed up until alomst all crystals are dissolved again and than cooled dwon a second time very slowly.

Explanation:

rystallization or crystallisation is the process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal. Some of the ways by which crystals form are precipitating from a solution, freezing, or more rarely deposition directly from a gas.

Answer:

We use radio waves for communicating or a for television and radio. We use Heat waves to heat things. We uses heat waves everyday for heat up food in the microwave and drying clothing when using the dryer or when drying our hair with a hairdryer. Infrared light is used by electrical heaters, cookers for cooking food, and by infrared cameras which detect people in the dark.

Hopefully, it helps :) Give me brainiest please!

Answer:

B

Explanation:

IM A CHEMISTRY WIZZZZ

:)

I hope u get full marks on your paper/test/quiz or whatever!

There is a 20 percent chance so stay positive!

Answer:

D

Explanation: ultraviolet rays are harmful to humans

Answer:

2HNO3 + Mg(OH)2 --> 2H2O + Mg(NO3)2

593.2 grams Mg(NO3)2

Explanation:

First, balance the equation

The first thing I notice is that there are 2 nitrates on the reactant side so I would put a 2 in front of HNO3. Now the problem is that there are 4 hydrogens on the reactants side, so add a 2 to H2O.

Next is stoichiometry

We are looking for Mg(NO3)2 so use the balanced equation to create a mole ratio and then convert to grams.

8 mol HNO3 * 1 mol Mg(NO3)2/2 mol HNO3 * 148.3 g Mg(NO3)2/1 mol Mg(NO3)2 = 593.2 grams Mg(NO3)2

593.2 grams of Magnesium Nitrate [[tex]Mg(NO_3)_2[/tex]] are produced.  

Balancing the equation we get:

[tex]2HNO_3 + Mg(OH)_2 = 2H_2O + Mg(NO_3)_2[/tex]

Here we can see that [tex]2HNO_3[/tex]  produces [tex]1Mg(NO_3)_2[/tex]

It implies that to make 1 mole of [tex]Mg(NO_3)_2[/tex] we need 2 moles of [tex]2HNO_3[/tex]

Therefore in 8 moles of  [tex]2HNO_3[/tex] , 4 moles of [tex]Mg(NO_3)_2[/tex]will be produces.

Now, 1 mole of [tex]Mg(NO_3)_2[/tex] = 148.3 g

       4 moles of [tex]Mg(NO_3)_2[/tex] = 4 × 148.3 g = 593.2 g of magnesium nitrate will be produced.

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Answer:

Initially there is 100 g of potassium nitrate in solution, at 50 °C the solubility is 84 g/100g (original data or graph), so 16 g will have crystallised out

Explanation:

Answer:

1st group-alkali metals

7th group-halogen group

8th group- noble gas group

Answer:

4. Group 1 in periodic table is called alkali metals.

5. Group 7 in periodic table is called halogens.

6. Group 8 or 0 in periodic table is called noble gases.

Answer:

the different things that we have and animals are.:

Answer:

Explanation:

mass of 1mole of brick =  mass of 1 brick x avagadro number

= 4 kg x 6.022 x 10^23 bricks  = 2.4 x 10^24 kg

No. of moles of bricks have a mass equal to the mass of the earth

= mass of earth / mass of 1 mole of brick

= [ 6 x 10^27 ]  /  [ 2.4 x 10^24 ]

= 2.5 x 10^3

= 2500 moles

Answer:

B and D

Explanation:

it is B and D because in no gravity  if you change the size of the ball it does not change anything. and if you swing fast it does not change anything but the speed. if you change the angle it is just the same modle but different angle

Answer:

D, and E

Explanation:

they may not be correct but the answers seem correct. please tell me If I'm wrong.

Answer:

40.3044 g/mol

Explanation:

The answer is gold.

Substance: Specific Heat (C) in joules per gram/degrees centigrade:

Water (ice) 2.05

Iron 0.46

Aluminium 0.90

Gold 0.13

Copper 0.39

Ammonia (liquid) 4.70

Ethanol 2.44

Gasoline 2.22

Water (liquid) 4.18

Water (vapor) 2.08

Air (25 degrees Celsius) 1.01

Oxygen 0.92

Hydrogen 14.30

To know that we clear the equation q=m*C*Δt for the specific heat (C) and solve the equation. Keep in mind that we need to use the heat (520 J) in Joules since the values from the question and the table are in Joules.

q/m∗ΔT = C = 520J/200g∗(45degC−25degC) =

0.13J/gdegC

As you can see, the substance that has this specific heat is GOLD.

The value of specific heat for the given data in the question will be for gold:-

[tex]C= 0.13\ \dfrac{J}{g^oC}[/tex]

Specific heat can be defined as the amount of heat one kg or gram substance can absorb or release for a unit temperature difference.

The formula for the heat will be:-

[tex]Q=mc\Delta T[/tex]

m= Mass of substance

c= specific heat of the substance

[tex]\Delta T[/tex]= Temperature difference

Now the given data is

m= 200 g

Q= 520 J

[tex]\Delta T[/tex]=  (45-25)=20

[tex]Q=mc\Delta T[/tex]

[tex]520=200\times C\times 20[/tex]

[tex]C= \dfrac{520}{200\times 20} =\dfrac{520}{4000} =0.13\ \dfrac{J}{g ^oC}[/tex]

Since the value of specific gold  is  [tex]0.13\ \dfrac{J}{g ^oC}[/tex]

Thus the value of specific heat for the given data in the question will be for gold:-

[tex]C= 0.13\ \dfrac{J}{g^oC}[/tex]

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