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UNO [17]
3 years ago
11

The rock record indicates that photosynthesis began on Earth about 3.5 million years ago.

Chemistry
2 answers:
Oksana_A [137]3 years ago
8 0

I put true into the answer and it was wrong so it is actually FALSE.

<u>The answer above is incorrect.</u>

riadik2000 [5.3K]3 years ago
7 0

Answer;

The above statement is false

Explanation;

Photosynthesis is the biological conversion of light or electromagnetic energy from the Sun into chemical energy. It occurs in green plants, algae, and some types of bacteria, and requires a series of biochemical reactions.

In photosynthesis, carbon dioxide and water react with one another in the presence of light and a chemical known as chlorophyll to produce a simple carbohydrate and oxygen.

Fossils of what are thought to be filamentous photosynthetic organisms have been dated at 3.4 billion years old. Geological evidence suggests that oxygenic photosynthesis, such as that in cyanobacteria, became important during the Paleoproterozoic era around 2 billion years ago.

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Hydrogen bonding occurs when hydrogen is bonded to N, O, or F. Which of the following molecules has hydrogen bonding, when bondi
Makovka662 [10]

Answer:

I think the answer is……

O B.H2S

Explanation:

I’m not sure tho, I’m just not 100% positive.

5 0
3 years ago
4. Find the pH at each of the following points in the titration of 25 mL of 0.3 M HF with 0.3 M NaOH. The Ka value is 6.6x10-4 a
yawa3891 [41]

Explanation:

Since HF is a weak acid, the use of an ICE table is required to find the pH. The question gives us the concentration of the HF.

HF+H2O⇌H3O++F−HF+H2O⇌H3O++F−

Initial0.3 M-0 M0 MChange- X-+ X+XEquilibrium0.3 - X-X MX M

Writing the information from the ICE Table in Equation form yields

6.6×10−4=x20.3−x6.6×10−4=x20.3−x

Manipulating the equation to get everything on one side yields

0=x2+6.6×10−4x−1.98×10−40=x2+6.6×10−4x−1.98×10−4

Now this information is plugged into the quadratic formula to give

x=−6.6×10−4±(6.6×10−4)2−4(1)(−1.98×10−4)−−−−−−−−−−−−−−−−−−−−−−−−−−−−√2x=−6.6×10−4±(6.6×10−4)2−4(1)(−1.98×10−4)2

The quadratic formula yields that x=0.013745 and x=-0.014405

However we can rule out x=-0.014405 because there cannot be negative concentrations. Therefore to get the pH we plug the concentration of H3O+ into the equation pH=-log(0.013745) and get pH=1.86

6 0
3 years ago
how many ml of a 22.5% (v/v) ethanol solution would you need to measure out in order to have 12.5 ml of ethanol ?
Aleks [24]
Volume percent<span> or </span>volume/volume percent<span> (v/v%) is used when preparing solutions of liquids. It will have units of volume of the smaller composition substance over the volume of the solution. We calculate as follows:

12.5 mL ethanol = .225 mL ethanol / 1 mL solution ( V )
V = 55.56 mL of the 22.5 % by volume ethanol solution is needed

Hope this answers the question.</span>
8 0
3 years ago
A combustion reaction is one type of what class of reactions?
ivanzaharov [21]
It is a. oxidation-reduction
6 0
3 years ago
What are the simplest organic compounds called?
riadik2000 [5.3K]

<u>Answer:</u>

<u>Answer:hydrocarbons</u>

Explanation:

The simplest organic compounds are the hydrocarbons, which contain only carbon and hydrogen. Alkanes contain only carbon–hydrogen and carbon–carbon single bonds, alkenes contain at least one carbon–carbon double bond, and alkynes contain one or more carbon–carbon triple bonds.

4 0
3 years ago
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