The first major source of oxygen gas was _____.a. volcanic outgassing
b. meteorite impacts
c. cyanobacteria
d. banded iron formations

Answers

Answer 1

Answer: The first major source of life on Earth was c. cyanobacteria. These organisms produce food by using energy from the sun; they are photosynthetic organisms. Over millions of years these organisms used CO2 in the air for photosynthesis and released oxygen as a byproduct. Over time oxygen concentrations rose high enough to support life.

Answer 2

Answer: The word that best fits in the blank in the sentence, "The first major source of oxygen gas was _____" is cyanobacteria. Thus, the answer is letter C. Cyanobacteria are blue-green algae and they are believed to have caused the "great Oxidation Event".

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Waves with the shortest wave lengths have the highest

A 5.0-gram sample of zinc and a 50.-milliliter sample of hydrochloric acid are used in a chemical reaction. Which combination of these samples has the fastest reaction rate?(1) a zinc strip and 1.0 M HCl(aq)
(2) a zinc strip and 3.0 M HCl(aq)
(3) zinc powder and 1.0 M HCl(aq)
(4) zinc powder and 3.0 M HCl(aq)

Answers

Answer:

(4) zinc powder and 3.0 M HCl(aq)

Explanation:

First consider the equation of reaction:

$Zn + 2HCl --> ZnCl_2 + H_2$

1 mole of Zinc requires 2 moles of HCl for reaction.

mole of zinc = mass/molar mass = 5.0/65.38 = 0.0765 mole

0.0765 mole of zinc will require: 0.0765 x 2 = 0.1530 mole HCl

Mole of 1.0 M HCl = Molarity x volume = 1 x 0.05 = 0.05 mole

Mole of 3.0 M HCl = 3 x 0.05 = 0.15

Hence, the 3.0 M HCl is what will give the required number of mole.

Zinc in powder form will react faster compared to in strip because the former has higher surface area for reaction.

Therefore, zinc powder and 3.0 M HCl will give the fastest reaction rate.

The correct option is option 4.

The answer is Zine powder and 3.0 M HCl (aq)

Juan created a chart to help him study for a test.A 2-column table. The first column labeled X has entries some light is reflected, some light is absorbed, no light passes through. The second column labeled Y has entries some light is reflected, some light is absorbed, some light is reflected, most light passes through.

Which headings best complete the chart?

X: Transparent Objects
Y: Opaque Objects
X: Opaque Objects
Y: Transparent Objects
X: High Frequency Waves
Y: Low Frequency Waves
X: Low Frequency Waves
Y: High Frequency Waves

Answers

The light in the electromagnetic spectrum which passes in first case is through opaques objects while in second case it is transparent objects.

What is an electromagnetic spectrum?

The electromagnetic radiation consists of waves made up of electromagnetic field which are capable of propogating through space and carry the radiant electromagnetic energy.

The radiation are composed of electromagnetic waves which are synchronized oscillations of electric and magnetic fields . They are created due to change which is periodic in electric as well as magnetic fields.

In vacuum ,all the electromagnetic waves travel at the same speed that is with the speed of air.The position of an electromagnetic wave in an electromagnetic spectrum is characterized by it's frequency or wavelength.They are emitted by electrically charged particles which undergo acceleration and subsequently interact with other charged particles.

Learn more about electromagnetic spectrum,here:

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Answer:

B) X: Opaque Objects

Y: Transparent Objects

Explanation:

Just had this question and got it right

The metalloid that has three valence electrons is?

Answers

The metalloid that has three valence electrons is Boron~

Answer:

The metalloid that has three valence electrons is Boron~

Explanation:

Which is not a functional group?
a)amino
b)carboxyl
c)halide
d)hydroxyl

Answers

The correct answer is C. Halide is not a functional group. Instead, it is a halogen atom having a negative charge. These halide ions are fluoride, chloride, iodide, astatide and bromide.

Why do atoms with greater numbers of protons have greater electronegativity?

Answers

Answer:

the positivity charged protons in the nucleus attract the negatively charged elections.bas the number of protons in the nucleus increases, the electronegativity or attraction will increase

The distance between stars is typically measured in

Answers

The distance between stars is typically measured in light years, or the amount of distance traveled by light in one year. This is because stars are extremely far apart, and measuring the distance with a smaller unit of measurement would result in ridiculously large numbers that would be difficult to work with.

Final answer:

The typical measure for the distance between stars is the light-year. Light-year and parsec are units used to quantify the enormous distances in the universe.

Explanation:

The distance between stars is typically measured in light-years. This term, 'light-year', refers to the distance that light can travel in one year, which is approximately 9.461 trillion kilometers or 5.879 trillion miles. Another less commonly used unit is the parsec, which is equivalent to about 3.26 light years. Such large units are necessary due to the vast distances between stars in the universe.

So, The distance between stars is typically measured in light-years.