can someone plz help me with science.
Order the items from smallest at the top to largest at the bottom. cell,elephant,human body,school bus,organ,molecule.
​

Answer:

a new substance was forming

Explanation:

Explanation:

The compound disilicon tetraoxide has the formula;

        Si₂O₄;

 This compound is held together by a polar covalent bond. A polar covalent bond occurs between two species that shares electrons. In this bond type, the more electronegative element draws the shared electrons more closer to itself.

Answer:

2.3 * 1,000 = 2,300

Explanation:

Answer:

-171.79 KJ

Explanation:

We must keep in mind that water freezes at 0 degrees centigrade

Recall that heat lost during freezing can be obtained from;

H = mc(θ2 - θ1)

m = mass of the water = 350 g/1000 = 0.35 Kg

c = specific heat capacity of water = 4,200 J/kg°C

θ2 = final temperature = 0°C

θ1 = initial temperature = 37°C

H= 0.35 * 4,200 * (0 - 37)

H = -54390 J = -54.39 KJ

Energy given out when 1 mole of water freezes at its freezing point = -6.04 kJ

For 350 g of water; 350 g/18 g/mol *  -6.04 kJ  = -117.4 kJ

Hence total energy removed = (-54.39 KJ) + (-117.4 kJ) = -171.79 KJ

Answer: 1.91 moles

Explanation:

First you want to find the molar mass of NaCL

Na = 22.99g  Cl = 35.45g

22.99g + 35.45g = 54.44g

Then divide 111.5g by 54.44g and this will give you moles.

Answer:

the one with less thermal energy

Explanation:

thermal energy is heat

Answer:

GOTTTEM

Explanation:

Nice written.

Is it written by you yourself or you have copied it from somewhere?

Answer:

Percent yield =  57%

Explanation:

Given data:

Mass of nitrogen = 15.0 g

Mass of hydrogen = 15.0 g

Mass of ammonia produced = 10.5 g

Percent yield = ?

Solution:

Chemical equation:

N₂+ 3H₂      →   2NH₃

Number of moles of hydrogen:

Number of moles = mass/molar mass

Number of moles = 15.0 g/ 2 g/mol

Number of moles = 7.5 mol

Number of moles of nitrogen:

Number of moles = mass/molar mass

Number of moles = 15.0 g/ 28 g/mol

Number of moles = 0.54 mol

Now we will compare the moles of ammonia with nitrogen and hydrogen from balance chemical equation.

              N₂       :        NH₃

               1         :          2

           0.54       :     2×0.54 = 1.08

             H₂         :           NH₃

              3           :            2

              7.5        :      2/3×7.5= 5 mol

Theoretical yield of ammonia:

Mass = number of moles × molar mass

Mass = 1.08 × 17 g/mol

Mass = 18.36 g

Percent yield:

Percent yield = (actual yield / theoretical yield) ×100

Percent yield = (10.5 g/ 18.36 g) ×100

Percent yield = 0.57 ×100

Percent yield =  57%

Answer:

so they can find the aswer and not get hurt

Explanation:

The scientist Neil Bohr has investigated the atom to be young and unattached to Albert Einstein thinking because he is fearless of his thinking and ready to find an explanation.

Einstein model is called as Einstein solid model. He stated as ever solid atom oscillate with the same frequency and contain large number of three dimensional quantum harmonic oscillation.

Bohr atomic model stated that electron revolve around the nucleus in its stable orbital without emitting radiant energy. It is primitive model of hydrogen atom. Bohr has given the expression l = nh / 2π

Where n = principle quantum number, l = angular momentum and h = plank constant

Thus, the scientist Neil Bohr has investigated the atom to be young and unattached to Albert Einstein thinking because he is fearless of his thinking and ready to find an explanation.

To learn more about Einstein model, refer to the link below:

https://brainly.com/question/863905

#SPJ2

Answer:

it is false it cannot be a model

Answer:

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\[/tex]

From the question we have

[tex]density = \frac{23.73}{3.0} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

I think it would have a LOW frequency rate.

Explanation:

The answer to this is true.

Answer:

true

Explanation:

took test

Answer:

1. earth metal 2. halogen 3.The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups. ... Elements in the periodic table are organized according to their properties.

Inventor: Dmitri Mendeleev please name most brainliest

Answer:

Gosha Gosha

Explanation:

‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎‏‏‎ ‎

Answer:

A

Explanation:

Hopefully this helps

What, if anything, is wrong with the nuclear equation shown below?

a. the daughter product has the wrong atomic number.

b. The daughter product has the wrong mass number.

c. The particle labeled "e" should have a mass number of 1.

d. There is nothing wrong with the equation.

Answer:

a. the daughter product has the wrong atomic number.

Answer:

Do you want someone to go through and answer all of these questions??

Explanation:

I am on the dox, but idk if I could finish it fast enough to put the link in here. Is there a way to delete answers?

Answer:

The closest shell to the nucleus is called the "1 shell" (also called the "K shell"), followed by the "2 shell" (or "L shell"), then the "3 shell" (or "M shell"), and so on farther and farther from the nucleus.

Answer:

When manganese(IV) oxide is added to hydrogen peroxide, bubbles of oxygen are given off. To make oxygen in the laboratory, hydrogen peroxide is poured into a conical flask containing some manganese(IV) oxide. The gas produced is collected in an upside-down gas jar filled with water.

Answer:

28g

Explanation:

Given parameters:

Number of moles of hydrogen  = 3moles

Unknown:

Mass of nitrogen used = ?

Solution:

 To solve this problem, let us establish the balanced reaction equation first;

             N₂  + 3H₂ →  2NH₃

From the balanced reaction equation;

                 3 mole of H₂ will combine with 1 mole of N₂

Now,

   Mass of Nitrogen  = number of moles x molar mass

         Molar mass of N₂  = 2(14) = 28g/mol

   Mass of Nitrogen  = 1 mole x 28g/mole  = 28g

Answer:

If we have more protons in the nucleus, then they hold it tighter

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\ [/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{1.204 \times {10}^{24} }{6.02 \times {10}^{23} } \\ [/tex]

We have the final answer as

Hope this helps you

ΔH for this reaction : -2668.4 (exothermic)

The change in enthalpy in the formation of 1 mole of the elements is called enthalpy of formation  

The enthalpy of formation measured in standard conditions (25 ° C, 1 atm) is called the standard enthalpy of formation (ΔHf °)  

(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)  

The value of ° H ° can be calculated from the change in enthalpy of standard formation:  

∆H ° rxn = ∑n ∆Hf ° (product) - ∑n ∆Hf ° (reactants)  

you can search the value of ΔHf on the internet

∆H ° rxn =( ∆H Al₂O₃+∆H AlCl₃+3.∆H NO + 6.∆H H₂O)-(∆H Al+∆H NH₄ClO₄)

[tex]\tt \Delta H^o~rxn=(-1669.8+-704+(3\times 90.4)+(6.\times -241.8)-(3\times 0+3\times -295)\\\\\Delta H6o~rxn=-3553.4+885=-2668.4~kJ/mol[/tex]

Answer:2:saturated

3:it got darker

4:it halved/unsaturated

Explanation:

Answer:

Answer:2:saturated

3:it got darker

4:it halved/unsaturated

Explanation:

Cl2 + 2RbI → 2RbCl + I2  is possible while I2 + NiBr2 → NiI2 + Br2 is not possible.

It will do us a lot of good to write out the equations again;

Cl2 + 2RbI → 2RbCl + I2       Yes

I2 + NiBr2 → NiI2 + Br2         No

If we look at the reaction closely, they are displacement reactions. It is worthy to note that a specie can only displace another specie which lies below it in the activity series. The activity series is an arrangement of elements in order of decreasing reactivity.

The activity series of the halogens is; fluorine > chlorine > bromine > iodine.

Since chlorine is above iodine in the activity series, Cl2 + 2RbI → 2RbCl + I2 is possible.

Iodine is less than bromine in the activity series hence the reaction  I2 + NiBr2 → NiI2 + Br2 is not possible.

Learn more: https://brainly.com/question/14365792

Answer:

Cl2 + 2RbI --> 2RbCl + I2 = yes

I2 + NiBr2 --> NiI2 + Br2 = no

Explanation:

I just took the assinment

Answer:

I think the particle size

Explanation:

By decreasing the particle size of a reactant, we are increasing its surface area. The greater the surface area, the higher the chance of collisions, thus the faster the rate of reaction.

increasing the particle size will decrease the rate of reaction.

conclusion:

The smaller the particle size the faster the reaction.

The statement which is not correct is that: the rate of a reaction increases with increasing particle size.

Discussion;

The addition of catalyst, increase in temperature and reactant concentration all are factors which increase the rate of a chemical reaction.

Decreasing the particle size of reactants also increases the rate of reaction. This is because upon decreasing particle size, the surface area of the reactants is increased and the reaction is able to take place at a faster rate.

Read more on rate of reaction;

https://brainly.com/question/24795637