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Aliun [14]
2 years ago
15

1. How can scientists use fossils in rock layers as evidence that one event happened earlier than another event?​

Chemistry
1 answer:
Komok [63]2 years ago
6 0

Answer:

Fossils in rock, in general, provide information about the creatures and plants that lived in the past.

The reason for this is that as those organisms die, they disintegrate and generate silts, which over millions of years go deep into the lithosphere.

As a result, scientists may use the radiocarbon dating technique to determine the age of the fossils. Another method is employed to determine the sort of organism that once existed.

As a result, scientists can infer proof that an event occurred on Earth as long as a million years ago through the application of these approaches.

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How does the volume of water change the solubility of sodium chloride in simple words?
kupik [55]

Answer:

When sodium chloride dissolves in water to make a saturated solution there is a 2.5 per cent reduction in volume. ... The solubility of salt does not change much with temperature, so there is little profit in using hot water.

3 0
3 years ago
Courtney Drive for 30 minutes at 50 mph and for one hour at 40 mph how far has he traveled all together
den301095 [7]

Answer:

Explanation:40 mph = 64.3738 kph

kph/3.6 = m/s

64.3738/3.6 = 17.8816 m/s

30 mins in seconds = 30 x 60 = 1800 s

1800 s x 17.8816 m/s = 32186.88 m or 32.18688 km or 20 miles

8 0
3 years ago
2
son4ous [18]

Answer: The molar enthalpy change is 73.04 kJ/mol

Explanation:

HCl+NaOH\rightarrow NaCl+H_2O

moles of HCl= molarity\times {\text {vol in L}}=0.415mol/L\times 0.1=0.0415mol

As NaOH is in excess 0.0415 moles of HCl reacts with 0.0415 moles of NaOH.

volume of water = 100.0 ml + 50.0 ml = 150.0 ml

density of water = 1.0 g/ml

mass of water = volume \times density=150.0ml\times 1.0g/ml=150.0g

q=m\times c\times \Delta T

q = heat released

m = mass  = 150.0 g

c = specific heat = 4.184J/g^0C

\Delta T = change in temperature = 4.83^0C

q=150.0\times 4.184\times 4.83

q=3031.3J

Thus 0.0415 mol of HCl produces heat = 3031.3 J

1 mol of HCL produces heat = \frac{3031.3}{0.0415}\times 1=73043.3J=73.04kJ

Thus molar enthalpy change is 73.04 kJ/mol

8 0
3 years ago
Sodium acetate can be formed from the metathesis/double replacement reaction of sodium
telo118 [61]

Answer:

Explanation:

Sodium Acetate Trihydrate BP Specifications

Sodium Acetate BP

C2H3NaO2,3H2O

Action and use

Used in solutions for dialysis; excipient.

DEFINITION

Sodium ethanoate trihydrate.

Content

99.0 per cent to 101.0 per cent (dried substance).

CHARACTERS

Appearance

Colourless crystals.

Solubility

Very soluble in water, soluble in ethanol (96 per cent).

IDENTIFICATION

A. 1 ml of solution S (see Tests) gives reaction (b) of acetates.

B. 1 ml of solution S gives reaction (a) of sodium.

C. Loss on drying (As shown in the Relevant Test).

TESTS

Solution S

Dissolve 10.0 g in carbon dioxide-free water prepared from distilled water R and dilute to 100 ml 100 ml with the same solvent.

Appearance of solution

Solution S is clear and colourless.

pH

7.5 to 9.0.

Dilute 5 ml of solution S to 10 ml with carbon dioxide-free water.

Reducing substances

Dissolve 5.0 g in 50 ml of water, then add 5 ml of dilute sulphuric acid and 0.5 ml of 0.002 M potassium permanganate. The pink colour persists for at least 1 h. Prepare a blank in the same manner but without the substance to be examined.

Chlorides

Maximum 200 ppm.

Sulphates

Maximum 200 ppm.

Aluminium

Maximum 0.2 ppm, if intended for use in the manufacture of dialysis solutions.

Arsenic

Maximum 2 ppm, determined on 0.5 g.

Calcium and magnesium

Maximum 50 ppm, calculated as Ca.

Heavy metals

Maximum 10 ppm.

Iron

Maximum 10 ppm, determined on 10 ml of solution S.

Loss on drying

39.0 per cent to 40.5 per cent, determined on 1.000 g by drying in an oven at 130C.

Sodium Acetate FCC Food Grade, US Food Chemical Codex

C2H3NaO2 Formula wt, anhydrous 82.03

C2H3NaO2·3H2O Formula wt, trihydrate 136.08

DESCRIPTION

Sodium Acetate occurs as colorless, transparent crystals or as a granular, crystalline or white powder. The anhydrous form is hygroscopic; the trihydrate effloresces in warm, dry air. One gram of the anhydrous form dissolves in about 2 mL of water; 1 g of the trihydrate dissolves in about 0.8 mL of water and in about 19 mL of alcohol.

Function: Buffer.

REQUIREMENTS

Identification: A 1:20 aqueous solution gives positive tests for Sodium and for Acetate.

Assay: Not less than 99.0% and not more than 101.0% of C2H3NaO2 after drying.

Alkalinity Anhydrous: Not more than 0.2%; Trihydrate: Not more than 0.05%.

Lead: Not more than 2 mg/kg.

Loss on Drying: Anhydrous: Not more than 1.0%; Trihydrate: Between 36.0% and 41.0%.

Potassium Compounds: Passes test.

5 0
3 years ago
Each year over _______ new organic compounds are produced.
antoniya [11.8K]
Each​ year over 100,000 new organic compounds are produce
7 0
3 years ago
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