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RSB [31]
3 years ago
9

The flow of energy through living systems can be modeled as food chains, food webs, or energy pyramids. The energy organisms nee

d to live and grow first enters the ecosystem when which of the following occurs? A. Plants take in light energy from the sun B. Decomposed break down dead organisms. C. Primary consumers East plants for food D. Secondary consumers eat primary consumers
Chemistry
1 answer:
aliya0001 [1]3 years ago
4 0

Answer:

A.......

Explanation:  The sun is the main source of energy

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The Density equation is:
Sergeu [11.5K]

Answer:

p=m/v

p equals density M equals mass and v = volume

6 0
2 years ago
White phosphorous has the chemical formula p4(s). a p4 molecule has 20 valence electrons. draw a lewis formula for a white phosp
aev [14]
The Lewis structure of P₄ is shown in 3-D form. The two bottom corner P atoms are facing right in front of us, one P atom behind the two, and one P above it. Each line represents 2 electrons. When you add the lone electrons, you get a total of 20 valence electrons.

Formal charge of each P:  5 - (2 +1/2*6) = 0

6 0
3 years ago
A weak monoprotic acid is titrated with 0.100 MNaOH. It requires 50.0 mL of the NaOH solution to reach the equivalence point. Af
larisa86 [58]

Explanation:

The given reaction is as follows.

        HA(aq) + NaOH (aq) \rightleftharpoons NaA(aq) + H_{2}O(l)

Hence, number of moles of NaOH are as follows.

        n = 0.05 L \times 0.1 M

           = 0.005 mol

After the addition of 25 ml of base, the pH of a solution is 3.62. Hence, moles of NaOH is 25 ml base are as follows.

             n = 0.025 L \times 0.1 M

                = 0.0025 mol

According to ICE table,

         HA(aq) + NaOH (aq) \rightleftharpoons NaA(aq) + H_{2}O(l)

Initial:     0.005 mol   0.0025 mol              0                  0

Change: -0.0025 mol  -0.0025 mol        +0.0025 mol

Equibm:   0.0025 mol    0                         0.0025 mol

Hence, concentrations of HA and NaA are calculated as follows.

          [HA] = \frac{0.0025 mol}{V}

        [NaA] = \frac{0.0025 mol}{V}

       [A^{-}] = [NaA] = \frac{0.0025 mol}{V}

Now, we will calculate the pK_{a} value as follows.

          pH = pK_{a} + log \frac{A^{-}}{HA}

       pK_{a} = pH - log \frac{[A^{-}]}{[HA]}

                  = 3.42 - log \frac{\frac{0.0025 mol}{V}}{\frac{0.0025}{V}}

                  = 3.42

Thus, we can conclude that pK_{a} of the weak acid is 3.42.

           

8 0
3 years ago
Each atom of protium has one proton, no neutrons, and one electron.Each atom of deutrium has one proton, two neutrons, and one e
Ket [755]

Answer:

These are the isotopes of same element. i.e. hydrogen.

Explanation:

Protium and deutrium are the isotopes of hydrogen.

Isotope:

Atoms of same elements can have different atomic mass but same atomic number . These atom of an elements are called isotopes.

Hydrogen consist of three stable isotopes protium, deutrium  and tritium.

These three isotopes are represented as H¹₁ , H²₁ and H³₁ respectively.

Protium consist of one proton and one electron while deutrium consist of one proton , one neutron and one electron. The number of neutron and proton is called mass number while number of electron or proton is called atomic number. The number of proton and electron are always same.That's why protium and deutrium have same atomic number but different atomic mass because there is no neutron present in protium that's why its atomic mass is less than by one from deutrium.

3 0
3 years ago
Which inquiry skill is based on identifying common features?
expeople1 [14]
<span>Classify is the answer hope this helps :)</span>
3 0
3 years ago
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