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2 years ago

Determine the mass in grams of 3.00 × 10²¹ atoms of arsenic. (The mass of one mole of arsenic is 74.92 g.)

Chemistry

1 answer:

Tpy6a [65]2 years ago

3 0

Answer:

The answer to your question is: 0.373 g

Explanation:

Data

mass = ? g

atoms = 3 x 10 ²¹

AM = 74.92 g

Process

1 mol of As ------------------ 6.023 x 10²³ atoms

x ------------------ 3 x 10 ²¹ atoms

x = 4.98 x 10⁻³ moles

1 mol ------------------------ 74.92 g

4.98 x 10⁻³ moles------- x

x = (4.98 x 10⁻³ x 74.92)/1

x = 0.373 g of As

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5 plates is the highest amount that can be served

There’s only 5 sandwiches so 7 is automatically ruled out, there’s 14 corn cobs and 5 sandwiches only need 10 so it works out

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2 years ago

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How does 0.5 m sucrose (molecular mass 342) solution compare to 0.5 m glucose (molecular mass 180) solution?

mash [69]

Answer : Both solutions contain $3.011 X 10^{23}$ molecules.

Explanation : The number of molecules of 0.5 M of sucrose is equal to the number of molecules in 0.5 M of glucose. Both solutions contain $3.011 x 10^{23}$ molecules.

Avogadro's Number is $N_{A}$ = $6.022 X 10^{23}$ which represents particles per mole and particles may be typically molecules, atoms, ions, electrons, etc.

Here, only molarity values are given; where molarity is a measurement of concentration in terms of moles of the solute per liter of solvent.

Since each substance has the same concentration, 0.5 M, each will have the same number of molecules present per liter of solution.

Addition of molar mass for individual substance is not needed. As if both are considered in 1 Liter they would have same moles which is 0.5.

We can calculate the number of molecules for each;

Number of molecules = $N_{A} X M$ ;

∴ Number of molecules = $6.022 X 10^{23} X 0.5 mol/L X 1 L$ which will be = $3.011 X 10^{23}$

Thus, these solutions compare to each other in that they have not only the same concentration, but they will have the same number of solvated sugar molecules. But the mass of glucose dissolved will be less than the mass of sucrose.

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1 year ago

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A 75 lb (34 kg) boy falls out of a tree from a height of 10 ft (3 m). i. What is the kinetic energy of the boy when he hits the

Jobisdone [24]

Answer:

Kinetic energy of boy just before hitting the ground is $\approx$ 1000 J.

Speed of boy just before hitting the ground is 7.67 m/s

or 17.16 mi/hr.

Explanation:

Given that:

Mass of boy = 75lb = 34 kg

Height, h = 10ft = 3m

To find:

Kinetic energy of boy when he hits the ground.

As per law of conservation of energy The potential energy gets converted to kinetic energy.

$\therefore$ Kinetic energy at the time boy hits the ground = Initial potential energy of the boy when he was at the Height 'h'

The formula for potential energy is given as:

$PE = mgh$

Where m is the mass

g is the acceleration due to gravity, g = 9.8 $m/s^2$

h is the height of object

Putting all the values:

PE = $34 \times 9.8 \times 3 \approx 1000\ J$

Hence, Kinetic energy is $\approx$ 1000 J.

Formula for Kinetic energy is:

$KE = \dfrac{1}{2}mv^2$

where m is the mass and

v is the speed

Putting the values and finding v:

$1000 = \dfrac{1}{2}\times 34 \times v^2\\\Rightarrow v^2 = 58.82\\\Rightarrow v = 7.67\ m/s$

Given that:

1 m = 1.094 yd and 1 mi = 1760 yd

$\Rightarrow 1609\ m = 1\ mi$

Converting 7.67 m/s to miles/hour:

$\dfrac{7.67 \times 3600}{1609}=17.16\ mi/h$

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2 years ago

The ph of a solution that contains 0.818 m acetic acid (ka = 1.76 x 10-5) and 0.172 m sodium acetate is __________.

crimeas [40]

PH is calculated using Handerson- Hasselbalch equation,

pH = pKa + log [conjugate base] / [acid]

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So,
pH = pKa + log [acetate] / [acetic acid]

We are having conc. of acid and acetate but missing with pKa,
pKa is calculated as,

pKa = -log Ka
Putting value of Ka,
pKa = -log 1.76 × 10⁻⁵

pKa = 4.75
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pH = 4.75 + log [0.172] / [0.818]

pH = 4.072

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2 years ago

What is an azeotrope? 2. Under what conditions is it better to perform a steam distillation (instead of, say, a simple distillat

aleksandrvk [35]

Answer:

Explanation:

1.)azeotrope is a mixture of two or more liquid components under constant boiling, it has a constant mole fraction composition of present component which can be homogeneous or heterogeneous.

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2 years ago