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Novosadov [1.4K]

2 years ago

11

An element has four naturally occurring isotopes with the masses and natural abundances given in the table below. Find the atomi

c mass of the element (express your answer to four significant figures and include the appropriate units).
Isotope Mass (amu) Abundance (%)
1 203.97304 1.390
2 205.97447 24.11
3 206.97590 22.09
4 207.97665 52.41
Identify the element, by spelling out its full name.

1 answer:

Anestetic [448]2 years ago

6 0

Answer:

Lead (Pb)

Explanation:

To find the atomic mass of the element, we need to take into consideration all the naturally occurring isotopes. We then find the atomic mass by multiplying the natural abundance of the isotopes by their mass for all of the isotopes and summing them together.

1. 1.390/100 * 203.97304 = 2.835225256

2. 24.11/100 * 205.97447 = 49.660444717

3. 22.09/100 * 206.97590 = 45.72097631

4. 52.41/100 * 207.97665 = 109.000562265

We then add all of these masses together:

109.000562265 + 45.72097631+ 49.660444717 + 2.835225256 = 207.217208548

To 4 sf = 207.2 amu

Element is Lead (Pb)

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Ipatiy [6.2K]

Your answer should be “C.”

MARK ME BRAINLIEST PLEASE!!!!!!

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2 years ago

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Your boss tells you that water at 68 F is flowing in a cooling tower loop at a rate of 600 gpm, in an 8-inch inside diameter pip

avanturin [10]

Explanation:

The volumetric flow rate of water will be as follows.

q = $600 gpm \times \frac{0.000063 m^{3} s^{-1}}{1 gpm}$

= 0.0378 $m^{3}/s
$

Diameter = $8 in \times \frac{0.0254 m}{1 in}$

= 0.2032 m

Relation between area and diameter is as follows.

A = $\frac{\pi}{4} \times D^{2}$

= $\frac{3.14}{4} \times (0.2032 m)^{2}$

= 0.785 x 0.2032 x 0.2032

= 0.0324 $m^{2}$

Also, q = A × V

or, V = $\frac{q}{A}$

= $\frac{0.0378 m^{3}/s}{0.0324 m^{2}}$

= 1.166 m/s

As, viscosity of water = 1 cP = $10^{-3}$ Pa-s

Density of water = 1000 $kg/m^{3}$

Therefore, we will calculate Reynolds number as follows.

Reynolds number = $\frac{D \times V \times density}{viscosity}$

= $\frac{0.2032 m \times 1.166 m/s \times 1000}{10^{-3}}$

= 236931.2

Hence, the flow will be turbulent in nature.

Thus, we can conclude that the Reynolds number is 236931.2 and flow is turbulent.

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2 years ago

A 101.2 ml sample of 1.00 m naoh is mixed with 50.6 ml of 1.00 m h2so4 in a large styrofoam coffee cup; the cup is fitted with a

Murrr4er [49]

The enthalpy change of the reaction when sodium hydroxide and sulfuric acid react can be calculated using the mass of solution, temperature change, and specific heat of water.

The balanced chemical equation for the reaction can be represented as,

$H_{2}SO_{4}(aq) + 2NaOH (aq) ----> Na_{2}SO_{4}(aq) + 2H_{2}O(l)$

Given volume of the solution = 101.2 mL + 50.6 mL = 151.8 mL

Heat of the reaction, q = $m C .$ Δ $T$

m is mass of the solution = 151.8 mL * $\frac{1 g}{1 mL} = 151.8 g$

C is the specific heat of solution = 4.18 $\frac{J}{g. ^{0}C}$

ΔT is the temperature change = $31.50^{0}C - 21.45^{0}C = 10.05^{0}C$

q = $151.8 g (4.18 \frac{J}{g ^{0}C})(10.05^{0}C) = 6377 J$

Moles of NaOH = $101.2 mL * \frac{1L}{1000 mL}*\frac{1.00 mol}{L} = 0.1012 mol$ NaOH

Moles of $H_{2}SO_{4}$ = $50.6 mL * \frac{1 L}{1000 mL} * \frac{1.0 mol}{1 L} = 0.0506 mol H_{2}SO_{4}$

Enthalpy of the reaction = $\frac{6377 J*\frac{1kJ}{1000J}}{0.0506 mol} = 126 kJ/mol$

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Which is something that a PURE SUBSTANCE and a SOLUTION have in common?

zhuklara [117]

D) They both look uniform (the same) throughout.

<h3>Further explanation</h3>

Pure substance can be any element or compound and is formed from one type of atom/molecule only

Meanwhile, the solution is included in a mixture consisting of 2 or more pure substance

Pure substance can be formed through a chemical process while the mixture is through a physical process

Mixture can be separated by physical processes into components of pure substance while pure substance cannot

The mixture itself consists of a homogeneous and heterogeneous solution

The mixture can be divided into a homogeneous mixture if the composition/ratio of each substance in the mixture is the same and a heterogeneous mixture if the ratio of the composition of the substances is not the same (can be varied) in each place.

Mixtures can also be divided into solutions, suspensions, and colloids based mainly on the size of the particles

Homogeneous mixture = Solution

Heterogeneous mixture = suspension, and

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yawa3891 [41]

Answer:

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..~-~~..

O=C=O

..~-~~..

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2 years ago