Please explain how we judge the brightness of stars.

1 answer:

6 0

Astronomers can measure it by way of luminosity which is the power of a star or the amount of energy (light) the star admits from its surface. they also measure the brightness of a start as if it were to appear 32.6 light years from Earth

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Review the PCR (Calvin-Benson-Basham) cycle and the photochemical (light) reactions. If photosynthesizing green algae are provid

stepladder [879]

Answer:

Explanation:

THE PHOTOCHEMICAL(LIGHT) REACTIONS :This is a phase of photosynthesis where sunlight is used as a source of energy to manufacture two chemical compounds which are "Reduced nicotinamide adenine dinucleotide phosphate"-NADPH and "Adenosine triphosphate"-ATP.This phase of photosynthesis involves 4 steps or reactions which are :

STEP 1 : Activation or Energization of chlorophyll - In this reaction,chlorophyll molecules in green algae or plants absorb sunlight and become activated,that is the electrons of the chlorophyll molecule acquire solar energy and become excited.

STEP 2 : PHOTOLYSIS OF WATER - Here the energy absorbed by the chlorophyll molecules are used to split water molecules into H+ ions and OH-- ions.

STEP 3:Formation of NADPH -The hydrogen ions (H+) produced reacts with an NADP ( an electron carrier in the chlorophyll) to form NADPH.

STEP 4: FORMATION OF ATP - The high energy generated from the electron transfer process or chain is used to add a phosphate group to ADP (Adenosine dphosphate) to form ATP.

DARK PHASE :In this phase of photosynthesis,the NADPH generated in the light phase is used as a reducing equivalent to reduce CO2 to form Glucose (food) using the ATP generated as a source of energy.

7 0

3 years ago

You have to prepare some 2 M solutions, with 10 g of solute in each. What volume of solution will you prepare, for each solute b

alexdok [17]

Answer:

0.045 L or 45 mL

Explanation:

Moles = Mass/M.Mass

Moles = 10 g / 109.94 g/mol

Moles = 0.09 moles

Also,

Molarity = Moles / Vol in L

Or,

Vol in L = Moles / Molarity

Vol in L = 0.09 mol / 2 mol/L

Vol in L = 0.045 L

8 0

2 years ago

Draw a lewis structure for ketene, c2h2o, which has a carbon–carbon double bond

MrMuchimi

Visual representation of covalent bonding indicating the valence shell electrons in the molecule, lines represents the shared pair of electron and pair of electrons that are not involved in bonding are represented as dots(lone pairs) are known as Lewis structures.

Compound formation takes place in order to complete the octet of each element that is according to octet rule, each atom forms bond with other atom in order to complete their octet that is to get eight electrons in its valence shell and attain stability.

An organic compound of the form $R^{'}R^{''}C=C=O$ is known as ketene.

The given ketene is $C_2H_2O$ .

The number of valence electron of:

$C = 4$

$H = 1$

$O = 6$

The number of valence electrons in $C_2H_2O$ = $2\times 4+2\times 1+1\times 6 =16$

2 electrons are involved in each single bond between carbon and hydrogen and 4 electrons are involved in each double bond formed between carbon-carbon and carbon-oxygen. Hence, the total number of electrons involved in bond formation are 12 and rest 2 pair of electrons are present on oxygen as lone pair of electrons.

Therefore, the attached image is the Lewis structure of $C_2H_2O$ .