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andrezito [222]
3 years ago
12

Help, Science test!Im stuck on this one​

Chemistry
1 answer:
mote1985 [20]3 years ago
4 0

Answer:

group d

Explanation: because it goes back the most amount of years

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How is the molar heat of sublimation related to the molar heats of vaporization and fusion? On what law are these relationships
Dovator [93]

Answer: Hsub=Hfus+Hvap

Explanation:

The molar heat of vaporization measured in kilojoules per mole, or kJ/mol is the energy needed to make vapor one mole of a liquid. .

The molar heat of sublimation measured in kilojoules per mole, or kJ/mol is the energy needed to sublime one mole of a solid,

the molar heat of fusion measured in kilojoules per mole, or kJ/mol is the energy needed to melt one mole of a solid.

Hess law helps to explain the relationship in physical chemistry stating that the total enthalpy change during the complete course of a reaction is the same whether the reaction is made in one step or in several steps.

In this context Hess’s law helps to see the several steps involved as the heat of sublimation energy is equal to the sum of vaporization energy and fusion energy.

3 0
3 years ago
Which reactant will be used up first if 78.1g of o2 is reacted with 62.4g of c4h10?
dlinn [17]

Answer:

Reagent O₂ will be consumed first.

Explanation:

The balanced reaction between O₂ and C₄H₁₀ is:

2 C₄H₁₀ + 13 O₂ → 8 CO₂ + 10 H₂O

Then, by reaction stoichiometry, the following amounts of reactants and products participate in the reaction:

  • C₄H₁₀: 2 moles
  • O₂: 13 moles
  • CO₂: 8 moles
  • H₂O: 10 moles

Being:

  • C: 12 g/mole
  • H: 1 g/mole
  • O: 16 g/mole

The molar mass of the compounds that participate in the reaction is:

  • C₄H₁₀: 4*12 g/mole + 10*1 g/mole= 58 g/mole
  • O₂: 2*16 g/mole= 32 g/mole
  • CO₂: 12 g/mole + 2*16 g/mole= 44 g/mole
  • H₂O: 2*1 g/mole + 16 g/mole= 18 g/mole

Then, by reaction stoichiometry, the following mass quantities of reactants and products participate in the reaction:

  • C₄H₁₀: 2 moles* 58 g/mole= 116 g
  • O₂: 13 moles* 32 g/mole= 416 g
  • CO₂: 8 moles* 44 g/mole= 352 g
  • H₂O: 10 moles* 18 g/mole= 180 g

If 78.1 g of O₂ react, it is possible to apply the following rule of three: if by stoichiometry 416 g of O₂ react with 116 g of C₄H₁₀, 62.4 g of C₄H₁₀ with how much mass of O₂ do they react?

mass of O_{2} =\frac{416grams of O_{2}*62.4 grams ofC_{4}H_{10}   }{116 grams of C_{4}H_{10}}

mass of O₂= 223.78 grams

But 21.78 grams of O₂ are not available, 78.1 grams are available. Since you have less mass than you need to react with 62.4 g of C₄H₁₀, <u><em>reagent O₂ will be consumed first.</em></u>

3 0
3 years ago
Which of the following molecules is the primary product of photosystem I?a) Carbon dioxideb) Oxygenc) NADPHd) ATP
Lina20 [59]

<u>Answer:</u>

The primary product of the photosystem I is NADPH.

<u>Explanation: </u>

NADPH is the acronym of Nicotinamide adenine Dinucleotide Phosphate. This NADPH plays a vital role in many chemical reactions that take place during  photosynthesis process. NADPH is released as a product in Photosystem I.

In the photosystem I process, the molecule present will absorb sunlight energy and transfers it to electrons to produce NADPH. This NADPH molecule is used as fuel for the chemical process that occurs during the 2nd stage of the photosynthesis process. Its molecular formula is C_{12} H_{30} N_{7} O_{17} P_{13}. It acts as a fundamental metabolite.

6 0
3 years ago
Students in a chemistry class are drawing molecular models based on molecular formulas they are given by the teacher.
Karo-lina-s [1.5K]
Sorry I need this marks
5 0
3 years ago
Lead(II) sulfide, PbS, reacts with oxygen gas to produce lead(II)oxide and dioxide. If 0.500 moles of O2 were consumed using thi
Andreas93 [3]
I think you mean:
".. reacts with oxygen gas to produce lead (II) oxide and 'sulfur' dioxide..."

The balanced chemical reaction would be
2PbS + 3O2 --> 2PbO + 2SO2

The stiochiometric ratio is this: 3 moles of O2 produces 2 moles of lead (II) oxide. So,

0.500 moles (2/3) = 0.333 moles

Therefore, 0.333 moles of PbO is produced when 0.500 moles of O2 reacts with PbS.
5 0
3 years ago
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