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Marta_Voda [28]
3 years ago
7

Which of the changes of state requires the removal of energy?

Chemistry
2 answers:
andrew11 [14]3 years ago
8 0

Answer:

condensation and freezing, hope this helps

Explanation:

anyanavicka [17]3 years ago
4 0

Answer: condensation and melting

Explanation: it requires the most energy

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Purest form of carbon is
vladimir2022 [97]

Answer:

Obtención. El carbono se encuentra - frecuentemente muy puro - en la naturaleza, en estado elemental, en las formas alotrópicas diamante y grafito. El material natural más rico en carbono es el carbón (del cual existen algunas variedades). Grafito: Se encuentra en algunos yacimientos naturales muy puro.

4 0
3 years ago
Read 2 more answers
Dr. House took two liquids of different densities (p_1=1500 kg/m^3; p_2 = 500 kg/m^3) are poured together into a 0.1 m^3 tank fi
SVETLANKA909090 [29]
We know that:
mass = density x volume
The volume of the total mixture is 0.1 m³
Let the first liquid be A and the second be B
Mass Total = Mass A + Mass B

800 x 0.1 = 1500Va + 500(0.1 - Va)
30 = 1000Va
Va = 0.03 m³
Vb = 0.1 - 0.03 = 0.07 m³
6 0
3 years ago
A common fuel additive that is composed of C, H, and O enhanced the performance of gasoline began being phased out in 1999 becau
spayn [35]

Answer:

C₅ H₁₂ O

Explanation:

44 g of CO₂ contains 12 g of C

30.2 g of CO₂ will contain 12 x 30.2 / 44 = 8.236 g of C .

18 g of H₂O contains 2 g of hydrogen

14.8 g of H₂0 will contain 1.644 g of  H .

total compound = 12.1 out of which 8.236 g is C and 1.644 g is H , rest will be O

gram of O = 2.22

moles of C, O, H in the given compound =  8.236 / 12 , 2.22 / 16 , 1.644 / 1

= .6863 , .13875 , 1.644

ratio of their moles = 4.946 : 1 : 11.84

rounding off to digits

ratio = 5 : 1 : 12

empirical formula = C₅ H₁₂ O

6 0
3 years ago
The atomic number of fluorine is 9. How many electrons does an ion of fluorine have if it is represented by the symbol shown bel
Irina-Kira [14]
  • See charge on ion is -1 .

Hence it has taken 1 electron

Now first look at EC of Fluorine(F)

\\ \bull\sf\dashrightarrow 1s^22s^22p^5

  • Now one electron added .hence no of electrons is 10now

Look at the EC

\\ \bull\sf\dashrightarrow 1s^22s^22p^6

Or

\\ \bull\sf\dashrightarrow [He]

Option C is correct.

5 0
2 years ago
Read 2 more answers
A particular radioactive nuclide has a half-life of 1000 years. What percentage of an initial population of this nuclide has dec
Delicious77 [7]

Answer:

91.16% has decayed & 8.84% remains

Explanation:

A = A₀e⁻ᵏᵗ => ln(A/A₀) = ln(e⁻ᵏᵗ) => lnA - lnA₀ = -kt => lnA = lnA₀ - kt

Rate Constant (k) = 0.693/half-life = 0.693/10³yrs = 6.93 x 10ˉ⁴yrsˉ¹

Time (t) = 1000yrs  

A = fraction of nuclide remaining after 1000yrs

A₀ = original amount of nuclide = 1.00 (= 100%)  

lnA = lnA₀ - kt

lnA = ln(1) – (6.93 x 10ˉ⁴yrsˉ¹)(3500yrs) = -2.426

A = eˉ²∙⁴²⁶ = 0.0884 = fraction of nuclide remaining after 3500 years

Amount of nuclide decayed = 1 – 0.0884 = 0.9116 or 91.16% has decayed.

3 0
3 years ago
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