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2 years ago

Convert 7.1x10^25 molecules of water to moles

Chemistry

1 answer:

ruslelena [56]2 years ago

8 0

Answer:

<h2>117.94 moles</h2>

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

$n = \frac{N}{L} \\$

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

$n = \frac{7.1 \times {10}^{25} }{6.02 \times {10}^{23} } \\ = 117.940199...$

We have the final answer as

<h3>117.94 moles</h3>

Hope this helps you

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Please help:/ I can’t figure out the answer

jekas [21]

Because other people cannot see what you are sending to somebody

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2 years ago

Why is Anton Von Leeuwenhoek important in the cell theory?

vesna_86 [32]

Answer:

He was the first scientist to observe and describe bacteria and protozoa by looking at a drop of water from a pound under a microscope. He also was the one to build the first compound microscope.

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3 years ago

Based on the three formulas shown, use one of them to solve for the purple yellow and red box and explain how you did it.

zysi [14]

P = 11.133 atm (purple)

T = -236.733 °C(yellow)

n = 0.174 mol(red)

<h3>Further explanation </h3>

Some of the laws regarding gas, can apply to ideal gas (volume expansion does not occur when the gas is heated),:

Boyle's law at constant T, P = 1 / V
Charles's law, at constant P, V = T
Avogadro's law, at constant P and T, V = n

So that the three laws can be combined into a single gas equation, the ideal gas equation

In general, the gas equation can be written

$\large {\boxed {\bold {PV = nRT}}}$

where

P = pressure, atm

V = volume, liter

n = number of moles

R = gas constant = 0.08206 L.atm / mol K

T = temperature, Kelvin

To choose the formula used, we refer to the data provided

Because the data provided are temperature, pressure, volume and moles, than we use the formula PV = nRT

Purple box

T= 10 +273.15 = 373.15 K

V=5.5 L

n=2 mol

$\tt P=\dfrac{nRT}{V}\\\\P=\dfrac{2\times 0.08205\times 373.15}{5.5}\\\\P=11.133~atm$

Yellow box

V=8.3 L

P=1.8 atm

n=5 mol

$\tt T=\dfrac{PV}{nR}\\\\T=\dfrac{1.8\times 8.3}{5\times 0.08205}\\\\T=36.42~K=-236.733^oC$

Red box

T = 12 + 273.15 = 285.15 K

V=3.4 L

P=1.2 atm

$\tt n=\dfrac{PV}{RT}\\\\n=\dfrac{1.2\times 3.4}{0.08205\times 285.15}\\\\n=0.174~mol$

3 0

2 years ago

815 yd to km (need 3 sig fig)

SpyIntel [72]

<u>Answer:</u> The correct answer is 0.745 km

<u>Explanation:</u>

We are given:

A numerical value of 815 yards

To convert this into kilometers, we use the conversion factor:

1 km = 1093.6 yards

Converting the given value into kilometers, we get:

$\Rightarrow 815yd\times \frac{1km}{1093.6yd}=0.745km$

Hence, the correct answer is 0.745 km

5 0

3 years ago

Show your work with good use of units, rounding, and significant figures. [Hint: it is good practice to show the value of your a

mel-nik [20]

Heat required : 4.8 kJ

<h3>Further explanation </h3>

The heat to change the phase can be formulated :

Q = mLf (melting/freezing)

Q = mLv (vaporization/condensation)

Lf=latent heat of fusion

Lv=latent heat of vaporization

The heat needed to raise the temperature

Q = m . c . Δt

1. heat to raise temperature from -20 °C to 0 °C

$\tt Q=10\times 2.09\times (0-(-20)=418~J$

2. phase change(ice to water)

$\tt Q=10\times 333=3330~J$

3. heat to raise temperature from 0 °C to 25 °C

$\tt Q=10\times 4.18\times (25-0)=1045~J$

$\tt Q~tot=418+3330+1045=4793~J\rightarrow rounding~and~2~sig~figs=4.8~kJ$

3 0

2 years ago