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2 years ago

What was the time frame?

Chemistry

1 answer:

faltersainse [42]2 years ago

7 0

Answer:

If you are referring to the Precambrian time, the answer is 500 Million Years Ago.

Explanation:

Precambrian time is the time period that started with the formation of Earth and ended about 500 million years ago.

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Would a thermos without a lid with water in it be an open or closed system? I'm so confused... also please explain your answer,

Dmitriy789 [7]

Answer:

. A closed system allows only energy transfer but no transfer of mass. Example: a cup of coffee with a lid on it, or a simple water bottle. ... In reality, a perfectly isolated system does not exist, for instance hot water in a thermos flask cannot remain hot forever.

8 0

2 years ago

What are the two different Energetics that relate to Environmental Science

Taya2010 [7]

Answer:

Organisms inhabit nearly every environment on Earth, from hot vents deep in the ocean floor to the icy reaches of the Arctic. Each environment offers both resources and constraints that shape the appearance of the species that inhabit it, and the strategies these species use to survive and reproduce. Some of the broadest patterns of environmental difference arise from the way our planet orbits the Sun and the resulting global distribution of sunlight (Chapin et al. 2002).

Explanation:

In the tropics, where solar radiation is plentiful year-round, temperatures are warm, and plants may photosynthesize continuously as long as water and nutrients are available. In polar regions, where solar radiation is seasonally limited, mean temperatures are much lower, and organisms must cope with extended periods when photosynthesis ceases.

3 0

2 years ago

As part of a soil analysis on a plot of land, a scientist wants to determine the ammonium content using gravimetric analysis wit

jeka94

Answer:

Mass percentage of NH₄Cl = 3.54%

Mass percentage of K₂CO₃ = 1.01%

Explanation:

If a 200.0 mL aliquot produced 0.105 g of KB(C₆H₅)₄, then a 100.0 mL aliquot would produce 1/2 * 0.105 g = 0.0525 g of KB(C₆H₅)₄.

Therefore, mass of NH₄B(C₆H₅)₄ in the 100.0 ml aliquot = (0.277 - 0.0525)g = 0.2245 g

Number of moles of NH₄B(C₆H₅)₄ in 0.2245 g = 0.2245 g/ 337.27 g/mol = 0.0006656 moles

In 500 ml solution, number of moles present = 0.0006656 * 500/100 = 0.003328 moles.

From equation of the reaction; mole ratio of NH₄⁺ and NH₄B(C₆H₅)₄ = 1:1

Similarly, mole ratio of NH₄⁺ and NH₄Cl = 1:1

Therefore, moles of NH₄Cl in 500 ml sample = 0.003328 moles

Mass of NH₄Cl = 0.003328 mol * 53.492 g/mol = 0.178 g

Mass percentage of NH₄Cl = (0.178/5.025) * 100% = 3.54%

Number of moles of KB(C₆H₅)₄ in 0.105 g (precipitated from 200.0 ml aliquot) = 0.105 g/ 358.33 g/mol = 0.000293 moles

In 500 ml solution, number of moles present = 0.000293 * 500/200 = 0.0007326 moles.

From equation of the reaction; mole ratio of K⁺ and KB(C₆H₅)₄ = 1:1

Similarly, mole ratio of K⁺ and K₂CO₃ = 2:1

Therefore, moles of K₂CO₃ in 500 ml sample = 0.0007326/2 moles = 0.0003663 moles

Mass of K₂CO₃ = 0.0003663 mol * 138.21 g/mol = 0.05063 g

Mass percentage of K₂CO₃ = (0.05063/5.025) * 100% = 1.01%

7 0

3 years ago

The pressure of a sample of helium in a 200. ml container is 2.0 atm. If the helium is compressed to a pressure of 40. atm witho

Crank

Answer:

$V_2=10mL$

Explanation:

Hello there!

In this case, according to the given information, it will be possible for us to solve this problem by using the Boyle's law as an inversely proportional relationship between pressure and volume:

$P_2V_2=P_1V_1$

In such a way, we solve for the final volume, V2, and plug in the initial volume and pressure and final pressure to obtain:

$V_2=\frac{P_1V_1}{P_2} \\\\V_2=\frac{2.0atm*200.mL}{40.atm}\\\\V_2=10mL$

Regards!

5 0

2 years ago

what is the balanced equation when copper metal is placed in a solution when platnium ii chloride is placed. what is the equatio

koban [17]

Answer:

$Cu~+~PtCl_2->Pt~+~CuCl_2$

Explanation:

In this case, we can start with the formula of Platinum (II) Chloride. The cation is the atom at the left of the name (in this case $Pt^+^2$ ) and the anion is the atom at the right of the name (in this case $Cl^-$ ). With this in mind, the formula would be $PtCl_2$ .