1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
stepan [7]
3 years ago
11

What can scientists learn from index fossils?

Chemistry
1 answer:
olga2289 [7]3 years ago
3 0

Answer:

dating and correlating the strata in which it is found

Explanation:

You might be interested in
Tris is a molecule that can be used to prepare buffers for biochemical experiments. It exists in two forms: Tris (a base) and Tr
ale4655 [162]

Solution :

For the reaction :

$\text{TrisH}^+ + H_2O \rightarrow \text{Trish}^- + H_3O^+$

we have

$Ka = \frac{[\text{Tris}^- \times H_3O]}{\text{Tris}^+}$

   $=\frac{x^2}{0.02 -x}$

  $=8.32 \times 10^{-9}$

Clearing $x$, we have $x = 1.29 \times 10^{-5} \text{ moles of acid}$

So to reach $\text{pH} = 7.8 (\text{pOH}= 14-7.8=6.2)$, one must have the $\text{OH}^-$ concentration of the :

$\text{[OH}^-]=10^{-pOH} = 6.31 \times 10^{-7} \text{ moles of base}$

So we can add enough of 1 M NaOH in order to neutralize the acid that is calculated above and also adding the calculated base.

$\text {n NaOH}=1.29 \times 10^{-5}+6.31 \times 10^{-7}$

            $= 1.35 \times 10^{-5} \text{ moles}$

Volume NaOH $= 1.35 \times 10^{-5} \text{ moles} \times \frac{1000 \text{ mL}}{1 \text{ mol}} = 0.0135 \text{ mL}$

Tris mass $H^+ = 0.02 \text{ mol} \times 157.6 \text{ g/mol}=3.152 \text{ g}$

Now to prepare the said solution we must mix:

$3.152 \text{ g Tris H} + 0.0135 \text{ mL NaOH} \ 1 M$ gauge to 1000 mL with water.

3 0
3 years ago
How can a flame test identify an unknown element?
Ilya [14]

Answer:

the answer for this question is the option D

6 0
3 years ago
Can someone help me with this pls
diamong [38]
The chemical elements are arranged in order of increasing atomic number. Answer A.
7 0
3 years ago
Read 2 more answers
Which is the best example of the heat through radiation
ICE Princess25 [194]
Heat from fire or heat from the sun warming your face
5 0
3 years ago
Read 2 more answers
Iodine monochloride (ICl) has a higher boiling point than bromine (Br2) partly because iodine monochloride is a(n)
tekilochka [14]

Answer: polar molecule.

Explanation:

The boiling point is the temperature at which the vapor pressure of a liquid equals the external pressure surrounding the liquid. The boiling point is dependent on the type of forces present.

Iodine monochloride (ICl) is a polar molecule due to the difference in electronegativities of iodine and chlorine. Thus the molecules are bonded by strong dipole dipole forces. Thus a higher temperature is needed to generate enough vapor pressure.

Bromine (Br_2) is a non polar molecule as there is no electronegativity difference between two bromine atoms. The molecules are bonded by weak vanderwaal forces and thus has low boiling point.

7 0
2 years ago
Other questions:
  • What is the compound of KCN called
    12·2 answers
  • Name an example of a d-block element having one 4s electron.
    13·1 answer
  • The following chemical equation is unbalanced. When the equation is balanced, what is the coefficient for pure calcium (Ca)? A.
    9·2 answers
  • Calculate the magnitude and direction (i.e., the angle with respect to the positive H-axis, measured positive as counter-clockwi
    14·1 answer
  • An archaeologist finds 14C in a sample of material to be decaying at 20 Geiger Counter clicks per second. A modern equivalent sa
    7·1 answer
  • QUESTION 10
    12·1 answer
  • A population of snails lives in a large field. As the size of the population grows, individual organisms on one side of the fiel
    8·2 answers
  • How does balancing equations prove the law of conservation<br> of matter?
    7·1 answer
  • a neutral atom is bombarded with sufficient energy that an electron is liberated. the result is called
    14·1 answer
  • How is a double displacement reaction completed and balanced
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!