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3 years ago

What is the average isotope mass?

Chemistry

2 answers:

Aleksandr [31]3 years ago

8 0

Answer:

the atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope

Explanation:

Average atomic mass = f1M1 + f2M2 + … + fnMn where f is the fraction representing the natural abundance of the isotope and M is the mass number (weight) of the isotope. The average atomic mass of an element can be found on the periodic table, typically under the elemental symbol.

Aliun [14]3 years ago

5 0

Answer:

he atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope.

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A chemistry teacher is able to grade chemistry labs at a rate of 5 labs for every 3 minutes. They need to grade 165 labs how man

PIT_PIT [208]

Answer:

1.65hr

Explanation:

Given parameters:

Number of labs = 5 labs

Time taken = 3 minutes

Unknown:

Time taken in hours to grade 165 labs = ?

Solution:

Let us find the rate of the teacher;

Rate = $\frac{number of labs}{time}$

Insert the parameters and solve;

Rate = $\frac{5}{3}$ = 1.67labs/min

Now;

Time to grade 165 labs = $\frac{number of labs}{rate}$

Time to grade 165 labs = $\frac{165}{1.67}$ = 98.8min

Since;

60min = 1hr

98.8min = $\frac{98.8}{60}$ = 1.65hr

3 0

3 years ago

What causes a disturbance that results in a wave

katovenus [111]

Force is a disturbance that results in a wave.

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4 years ago

Read 2 more answers

Calculate the volume occupied by 55.5 moles of water at STP.

Tems11 [23]

Answer:

Volume occupied by 55.5 moles of water gas at STP = 1240 Liters.

Explanation:

1st keep in mind that 'volume' in the context of problems like this apply only to the gas phase form of the substance. Water in solid form (ice) or liquid form (liquid water) do not apply. Volume in this case is referred to as 'molar volume' and is a gas occupying 22.4 liters at STP conditions (0°C, 1Atm).

So, if 1 molar volume of water gas (steam) occupies 22.4 Liters at STP, then 55.5 moles of water gas occupies 22.4 Liters/mole x 55.5 moles = 1243.2 Liters, or 1240 Liters (3 sig. figs.). :-)

4 0

3 years ago

½O2(g) + H2(g) ⇌ H2O(g)

ira [324]

Answer:

-241.826 kJ·mol⁻¹; -146.9 J·K⁻¹mol⁻¹; 664.6 J·K⁻¹mol⁻¹; spontaneous

Explanation:

½O₂(g) + H₂(g) ⟶ H₂O(g)

ΔHf°/kJ·mol⁻¹: 0 0 -241.826

S°/J·K⁻¹mol⁻¹: 205.0 130.6 188.7

1. ΔᵣH

ΔᵣH = products -reactants = -241.826 -(0 + 0) = -241.826 kJ·mol⁻¹

2. ΔᵣS

ΔᵣS = products - reactants = 188.7 - (205.0 + 130.6) = 188.7 - 335.6 = -146.9 J·K⁻¹mol⁻¹

3. ΔS(univ)

$\begin{array}{rcl}\Delta S_{\text{univ}} &=& \Delta S_{\text{sys}} +\Delta S_{\text{surr}}\\\\ &=& \Delta S_{\text{sys}} -\dfrac{\Delta H_{\text{sys}}}{T}\\\\& = & -146.9 - \dfrac{-241826}{298}\\\\& = & -146.9 + 811.5\\& = & \mathbf{664.6 \,\, J\cdot K^{-1}mol^{-1}}\\\end{array}$

4. Spontaneity

$\begin{array}{rcl}\Delta G &=& \Delta H - T\Delta S\\& = & -241.826 - 298 \times (-0.1469)\\& = & -241.826 + 43.776\\& = & \textbf{-198.050 kJ}\cdot\textbf{mol}^{\mathbf{-1}}\\\end{array}$

ΔG is negative, so the reaction is spontaneous.

4 0

3 years ago

Part of an important cellular process involving a DNA strand is modeled below

ivann1987 [24]

Answer: transcribing information to the dna sequence for use by the cell

Explanation:

4 0

3 years ago