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3 years ago

The age of the solar system is estimated by the dating of rocks. True or False

Chemistry

2 answers:

pshichka [43]3 years ago

7 0

True, the age is estimated by the dating of meteorites.

Sonbull [250]3 years ago

3 0

True.
Hope this helps. please give brainliest

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The molar absorptivity of a tyrosine residue at 280 nm is 2000 M-1cm-1, while for tryptophan it is 5500 M-1cm-1. A protein has b

adelina 88 [10]

Answer:

There are 4 tryptophans in the protein.

Explanation:

According to question, protein contains one tyrosine residue and say x number of tryptophans.

Concentration of protein solution = 1.0 micromolar = $1.0\times 10^{-6} Molar$

Molar absorptivity of a protein solution : $\epsilon$

$\epsilon = \epsilon _{tyro}+\epsilon _{tryp}$

$=1\times 2000 M^{-1}cm^{-1}+x\times 5500 M^{-1}cm^{-1}$

Length of the cuvette = l = 1.0 cm

Absorbance of protein solution at 280 nm = A = 0.024

$A=\epsilon \times l\times c$ ( Beer-Lambert's law)

$0.024=(1\times 2000 M^{-1}cm^{-1}+x\times 5500 M^{-1}cm^{-1})\times 1 cm\times 1.0\times 10^{-6} M$

Solving for x :

x = 4

There are 4 tryptophans in the protein.

7 0

3 years ago

The observation that 20g of hydrogen gas always combines with 160g of oxygen gas to form 180g of water, even when there is more

mash [69]

Answer:

The answer is most likely A. Definite proportions

Explanation:

The Law of Definite proportions states that a given chemical compound always contains its component elements in fixed ratio (by mass) and does not depend on its source and method of preparation.

3 0

3 years ago

7. A 2.0 L container had 0.40 mol of He(g) and 0.60 mol of Ar(g) at 25°C.

Finger [1]

Answer:

a) Ek Ar > Ek He

b) v Ar < v He

c) If v Ar = 431 m/s ⇒ v He = 1710.44 m/s

d) Pt = 12.218 atm

e) P He = 4.887 atm and P Ar = 7.33 atm

Explanation:

container:

∴ V = 2.0 L

∴ n He = 0.4 mol

∴ n Ar = 0.6 mol

∴ T = 25°C ≅ 298 K

a) Internal energy (U) :

∴ U = Ek + Ep = kinetic energy + potential energy

∴ Ep: the potential interaction energy is neglected, assuming ideal gas mixture

⇒ U = Ek = N(1/2mv²)= 3/2 NKT

∴ N = nNo ....number of moleculas

∴ K = 1.380 E-23 J/K....Boltzmann's constant

∴ No = 6.022 E23 molec/mol....Avogadro's number

for He:

⇒ N = (0.4)(6.022 E23) = 2.4088 E23 molec

⇒ Ek = (3/2)(2.4088 E23)(1.380 E-23 J/K)(298) = 1485.892 J

for Ar:

⇒ N = (0.6)(6.022 E23) = 3.6132 E 23 molec

⇒ Ek = (3/2)(3.6132 E23)(1.380 E-23 J/K)(298) = 2228.838 J

** Ar gas has a greater average kinetic energy

b) He:

∴ N(1/2)mv² = (3/2)NKT

⇒ mv² = 3KT

⇒ v² = 3KT/m

⇒ v = √3KT/m

∴ m He = (0.4 mol)(4.0026 g/mol) = 1.601 g He = 1.601 E-3 Kg He

⇒ v = √(3(1.380 E-23)(298)/(1.601 E-3)) = 2.776 E-9 m/s He

Ar:

∴ m Ar = (0.6)(39.948 g/mol) = 23.969 g = 0.0239 Kg Ar

⇒ v = 6.99 E-10 m/s

** v Ar < v He

c) r = V Ar / v He = (6.99 E-10 m/s)/(2.776 E-9 m/s) = 0.252

∴ If v Ar = 431 m/s

⇒ v He = v Ar/0.252 = 431 m/s / 0.252 = 1710.44 m/s

d) Pt = ntRT / V

∴ nt = 0.4 + 0.6 = 1 mol

⇒ Pt = (1mol)(0.082 atm.L/K.mol)(298 K)/(2.00 L) = 12.218 atm

e) P He = nRT/V = (0.4)(0.082)(298)/2 = 4.8872 atm

⇒ P Ar = Pt - PHe = 12.218 - 4.8872 = 7.33 atm

3 0

3 years ago

Most full scuba tanks have a pressure of between 1,800 p.s.i. and 3,000 p.s.i. (pounds per square inch). Approximately 70 to 85

ArbitrLikvidat [17]

Answer: The Diver's air tank is filled with oxygen gas.

The filling of air tank while keeping in water can be explained in reference to the Charles' Law.

Charles' Law: It states that the volume of the ideal gas is directly proportional to the absolute temperature at constant pressure.

$V\propto T$ (at constant Pressure)

The Scuba tank contains cold water and is present at high pressure. The gas which is put in the tank will be compact and would not expand. As the temperature is low inside the tank, hence by using Charles' Law, the volume will also decrease inside the tank.

When the air tank is filled, it is always kept in a tub of water because the pressure is high and hence, more oxygen gas can be filled inside the air tank.

8 0

3 years ago

Read 2 more answers

An unsaturated solution is one that ________. an unsaturated solution is one that ________. contains the maximum concentration o

ziro4ka [17]

<span>An unsaturated solution is one that has a concentration lower than it's solubility. What happens is all of the solute dissolves in the solvent. For example, dumping a spoon of sugar into coffee ends up with an unsaturated solution. Because all the sugar dissolves into the solvent (the coffee).</span>

4 0

3 years ago