All categories

3 years ago

Will give brainliest!! Explain how extinct organisms have left their evidence behind, which scientists now study.

1 answer:

3 0

theyre fossils, when extinct beings such as dinosaurs died their bones would sometimes get stuck in clay or amber (i cant remember if theres any other types of rock) or sediment) and stay there for years and years then scientist called Paleontologists find them and study them. hope this helps:)

You might be interested in

Q2. 0.254 g of KHP (204 g/mol) titrated against 20.0 mL of unknown NaOH (40.0 g/mol) solution to get the end point of phenolpht

Vera_Pavlovna [14]

Answer:

Mass concentration (g/L) = 2.49g/L.

Explanation:

No. of moles = $\frac{mass}{molar mass}$

= $\frac{0.254}{204}$ = 0.001245 moles

Concentration of KHP (C1) in litres = n/v

= $\frac{0.001245}{0.02}$ = 0.062 mol/L

We know that:

$C_{1} V_{1}$ = $C_{2} V_{2}$

where c1v1 and c2v2 are the products of concentration and volumes of KHP and NaOH respectively.

Since mole ratio is 1 : 1.

1 mole of NaOH - 40g

0.001245 mole of NaOH = 40 × 0.001245 = 0.0498g

⇒0.0498g of NaOH was used during the titration

∴Mass concentration (g/L) = 0.0498g ÷ 0.02L

= 2.49g/L.

3 0

3 years ago

In a titration, 10.0 ml of 0.0750 M HCl(aq) is exactly neutralized by 30.0 ml of KOH(aq) of unknown concentration. What is the c

Sphinxa [80]

Answer: 0.0250

Explanation: 10 X 0.0750 = .75

.75 / 30 = 0.0250 M

4 0

4 years ago

[15 Points, Stoichiometry and Gases]

KiRa [710]

The reaction is

CaC₂(s) + 2H₂O (l) -----> Ca(OH)₂ (s) + C₂H₂ (g)

As we have data of gas ethyne (or acetylene), C₂H₂

We can calculate the moles of acetylene and from this we can estimate the mass of calcium carbide taken

the moles of acetylene will be calculated using ideal gas equation

PV =nRT

R = gas constant = 0.0821 Latm/molK

T = 385 K

V = volume = 550 L

P = Pressure = 1.25 atm

n = moles = ?

n = PV /RT = 1.25 X 550 / 0.0821 X 385 = 21.75 mol

As per balanced equation these moles of acetylene will be obtained from same moles of calcium carbide

moles of calcium carbide = 21.75mol

molar mass of CaC₂ = 40 + 24 = 64

mass of CaC₂ = moles X molar mass = 21.75 X 64 = 1392g

6 0

3 years ago

Read 2 more answers

Write the parts of the ear in their correct order of transfer of vibrations. to the brain.

dimaraw [331]

Answer:

The sound waves travel from the outer ear and in through the auditory canal, causing the eardrum, or tympanic membrane, to vibrate. This, in turn, causes the three small bones, known as the ossicles, or the hammer, the anvil and the stirrup, in the middle ear to move.

3 0

3 years ago

Read 2 more answers

Which set of characteristics accurately describes the physical properties of electrons in atoms

zloy xaker [14]

Answer: Option (A) is the correct answer.

Explanation:

When there occurs no change in the chemical composition of a substance then it is known as physical property.

For example, mass, volume, density are all physical properties.

Since, the mass of an electron is negligible and an electron holds a negative charge.

Therefore, negatively charged particle with very little mass accurately describes the physical properties of electrons in atoms.

7 0

3 years ago