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amm1812
3 years ago
10

Pls help

Chemistry
1 answer:
navik [9.2K]3 years ago
3 0
The Cambrian period, part of the Paleozoic era, produced the most intense burst of evolution ever known. The Cambrian Explosion saw an incredible diversity of life emerge, including many major animal groups alive today. Among them were the chordates, to which vertebrates (animals with backbones) such as humans belong. These included brachiopods, which lived in shells resembling those of clams or cockles, and animals with jointed, external skeletons known as arthropods—the ancestors of insects, spiders, and crustaceans. These toughened-up creatures represented a crucial innovation: hard bodies offering animals both a defense against enemies and a framework for supporting bigger body sizes.
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Citric acid is one component of some soft drinks. Suppose that 8 L of solution are made from 0.24 g of citric acid, C6H8O7. What
stealth61 [152]

Answer:

The correct answer is 0.15 × 10⁻³ M.

Explanation:

C₆H₈O₇ is the molecular formula of citric acid. The mass of the one mole of the substance that comprise Avogadro's no of molecules is termed as the molar mass of the substance.  

The molar mass of the citric acid (C₆H₈O₇) will be,  

6 × atomic mass of carbon + 8 × atomic mass of hydrogen + 7 × atomic mass of oxygen = 6×12 + 8×1 + 7×16 = 192. Thus, the molar mass of citric acid is 192 g/mol.  

The value of the solution given in the question is 8 L.  

The mass of citric acid given is 0.24 g or 240 mg, which can also be written as 240/1000 g or 240 × 10⁻³ g.  

The number of moles can be calculated by using the formula = mass / molar mass. Thus, by putting the values we get,  

= 240 × 10⁻³ g / 192 g/mol

= 1.25 × 10⁻³ mol

The number of moles of the solute present in the 1 liter of the solution is termed as the molarity of the solution. The formula of molarity or M is,  

= no of moles of solute / volume of solution in L

Now putting the values we get,  

= 1.25 × 10⁻³ mol / 8 L

= 0.156 × 10⁻³ M

Hence, the molarity of citric acid in the given solution is 0.15 × 10⁻³ M

4 0
4 years ago
How many atoms are there in a sample of lead with a mass of 6.8 g?
Leviafan [203]

Answer:

B

Explanation:

3 0
3 years ago
Find the density of an object that has a mass of 5 kg and a<br> volume of 50 cm3.
iren2701 [21]
  • Mass=5kg=5000g
  • Volume=50cm^3

\\ \rm\longmapsto Density=\dfrac{Mass}{Volume}

\\ \rm\longmapsto Density=\dfrac{5000}{50}

\\ \rm\longmapsto Density=100g/cm^3

4 0
3 years ago
Which characteristic is given by the angular momentum quantum number?
chubhunter [2.5K]

Answer:

orbital shape.

Explanation:

1) There are four quantum numbers to describe the electrons. These are:

i) Principal quantum number (n)

ii) Azimuthal quantum number (ℓ), also called angular momentum quantum number.

iii) Magnetic quantum number (m)

iv) Spin quantum number (s)

2) The principal quantum number tells the main energy level. It can be 1, 2, 3, 4, 5, 6, 7. It is related to the orbital size. 1 is a small orbital, 7 is a big orbital.

2) The Azimuthal quantum number (ℓ) or angular momentum quantum number may be a number between 0 and n - 1.

It tells the kind of orbital, which is its shape

The correspondence is:

0 = s orbital,

1 = p orbital,

2 = d orbital,

3 = f orbital.

3) Magnetic quantum number (m) tells the orientation. It can be from - ℓ to + ℓ

For example when ℓ = 1, the orbital is p, and the magnetic quantum number may be -1, 0, or +1, which corresponds to px, py, pz: the orientation of the p orbital in the space.

4) Spin quantum number (s) can be either +1/2 or -1/2.

JM~ Hope this helps you out

3 0
2 years ago
Galaxies that are moving away from Earth are
sweet [91]

Answer: (D) red shifted

6 0
3 years ago
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