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Lelechka [254]
4 years ago
5

30 POINTS!!! PLEASE I'M VERY DESPERATE!

Chemistry
1 answer:
Sergio039 [100]4 years ago
3 0

1) elements are composed of atoms, which are the tiny building blocks that compose matter.

2) Atoms resemble a solar system: the sun being the nucleus (protons and neutrons) and the electrons being the planets that orbit the nucleus.

3) Mostly everything (food, electronics, animals, plants, air)

4) The # of protons in the element

5) The same elements that were forged by stars are also present in us

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aqueous solutions of barium chloride and potassium carbonate combine to produce a precipitate. what are the spectator ions?​
nalin [4]

Answer:BaCl (aq)+ K2CO3 (aq)——> Ba2CO3 (aq) + KCl (aq)

Explanation:

The equation is already balanced and it is a double replacement reaction.

8 0
3 years ago
Identify the group or period that matches each description.
Mekhanik [1.2K]

Answer:

a.6th period

b.groupIIA

3 0
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The names of the components FeS, NaCl, and Al(3)O(2) all end in the suffix.
anastassius [24]

Answer:

A) -ide

Explanation:

FeS = iron(II) sulfide or ferrous sulfide

NaCl = Sodium chloride

Al(3)O(2) = Aluminium oxide

3 0
3 years ago
When sodium is excited in a flame, two ultraviolet spectral lines at lambda - 372.1 nm and lambda = 376.4 nm respectively are em
suter [353]
The wavelength that represented photons is at <span>lambda = 376.4 nm.
The wavelength with the higher energy is at </span><span>lambda - 372.1 nm.
The longer wavelength is, of course, </span> at lambda 376.4 <span>nm.
The wavelength with the higher frequency is </span> 376.4 <span>nm.</span><span>
</span><span>
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3 0
3 years ago
Read 2 more answers
Some instant cold packs contain ammonium nitrate and a separate pouch of water. When the pack is activated by squeezing to break
KIM [24]

Answer:

a) Endothermic

b) T₂ = 53.1 ºC

Explanation:

a) We are told that when the ammonium nitrate dissolves in water the pack gets cold so the system is absorbing heat from the surroundings and by definition it  is an endothermic process.

b) Recall that the heat, Q, is given by the formula:

Q = mcΔT    where  m is the mass of water,

                                 c is the specific heat of water, and

                                 ΔT is the change in temperature

We can determine the value for Q since we are given the heat of solution for the ammonium nitrate. From there we can calculate ΔT and finally answer our question.

Molar mass NH₄NO₃ = 80.04 g/mol

moles NH₄NO₃ = 50.0 g/ 80.04 g/mol = 0.62 mol

Q = 25.4 kJ/mol x 0.62 mol = 15.87 kJ = 15.87 kJ x 1000 J = 1.59 x 10⁴ J

Q = mcΔT ⇒ ΔT = Q/mc

ΔT = 1.59 x 10⁴ J/ (135 g x 4.184 J/gºC ) = 28.1 ºC

T₂- T₁ = ΔT ⇒ T₂ = ΔT  + T₁  = 28.1 ºC +25.0 ºC = 53.1 ºC

5 0
4 years ago
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