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AlekseyPX
3 years ago
14

What describes using organisms that were only alive during a specific time period to estimate the unknown age of items

Chemistry
2 answers:
djyliett [7]3 years ago
7 0
Law of superposition
patriot [66]3 years ago
4 0

Answer:

c i just took the test

Explanation:

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A giant mass of air that carries warm weather to regions of the earth?
Scilla [17]
Continental air masses are characterized by dry air near the surface while maritime air masses are moist .Polar air masses are characterized by cold air near the surface while tropical air masses are warm or hot. Arctic air masses are extremely cold.
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6 0
4 years ago
A compound contains sulfur, oxygen, and chlorine. Analysis shows that it contains by mass 26.95% sulfur and 59.61% chlorine. Wha
sladkih [1.3K]

Answer:

SCl₂

Explanation:

In order to know the empirical formula, we have to follow a series of steps.

Step 1: Divide each percentage by the atomic mass

S: 26.95/32.07 = 0.8403

Cl: 59.61/35.45 = 1.682

Step 2: Divide all the numbers by the smallest one.

S: 0.8403/0.8403 = 1

Cl: 1.682/0.8403 ≈ 2

The empirical formula of the compound is SCl₂.

7 0
3 years ago
Read 2 more answers
A buffer consists of 0.120 M HNO2 and 0.150 M NaNO2 at 25°C. pka of HNO2 is 3.40. a. What is the pH of the buffer? b. What is th
Mashcka [7]

Explanation:

It is known that K_{a} of HNO_{2} = 4.5 \times 10^{-4}.

(a)  Relation between K_{a} and pK_{a} is as follows.

                       pK_{a} = -log (K_{a})

Putting the values into the above formula as follows.

                      pK_{a} = -log (K_{a})

                                    = -log(4.5 \times 10^{-4})

                                     = 3.347

Also, relation between pH and  pK_{a} is as follows.

              pH = pK_{a} + log\frac{[conjugate base]}{[acid]}

                     = 3.347+ log \frac{0.15}{0.12}

                    = 3.44

Therefore, pH of the buffer is 3.44.

(b)   No. of moles of HCl added = Molarity \times volume

                                            = 11.6 M \times 0.001 L

                                             = 0.0116 mol

In the given reaction, NO^{-}_{2} will react with H^{+} to form HNO_{2}

Hence, before the reaction:

No. of moles of NO^{-}_{2} = 0.15 M \times 1.0 L

                                           = 0.15 mol

And, no. of moles of HNO_{2} = 0.12 M \times 1.0 L

                                               = 0.12 mol

On the other hand, after the reaction :  

No. of moles of NO^{-}_{2} = moles present initially - moles added

                                          = (0.15 - 0.0116) mol

                                          = 0.1384 mol

Moles of HNO_{2} = moles present initially + moles added

                               = (0.12 + 0.0116) mol

                                = 0.1316 mol

As, K_{a} = 4.5 \times 10^{-4}

           pK_{a} = -log (K_{a})

                         = -log(4.5 \times 10^{-4})

                         = 3.347

Since, volume is both in numerator and denominator, we can use mol instead of concentration.

As, pH = pK_{a} + log \frac{[conjugate base]}{[acid]}

            = 3.347+ log {0.1384/0.1316}

            = 3.369

            = 3.37 (approx)

Thus, we can conclude that pH after the addition of 1.00 mL of 11.6 M HCl to 1.00 L of the buffer solution is 3.37.

6 0
3 years ago
Determine the composition of each phase in a cu-40% ni alloy at 1300c,
Morgarella [4.7K]
To be able to answer this, you need to have a phase diagram of Cu-Ni alloy. Create a vertical line along 40% in the x-axis. Then, create a horizontal line along the temperature at 1,300°C. The intersection lies outside of the α-L boundary. <em>Therefore, the system consist solely of the L-phase: 100% L.</em>

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3 years ago
A force interaction requires at least a(n)
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C.) Action force unless it has potential/stored enerygy

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3 years ago
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