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3 years ago

A chemist needs 0.550 mol selenium for a reaction. What mass of selenium should a chemist use?

Chemistry

1 answer:

-BARSIC- [3]3 years ago

4 0

Answer:

The chemist would require to use 43.43 grams.

Explanation:

In order to solve this problem we need to know<u> how much do 0.550 moles of selenium weigh</u>. To do that we use selenium's<em> molar mass </em>and multiply it by the given number of moles:

0.550 mol * 78.96 g/mol = 43.43 g

The chemist would require to use 43.43 grams.

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In 1928, 47.5 g of a new element was isolated from 660 kg of the ore molybdenite. the percent by mass of this element in the ore

vitfil [10]

To take the percent by mass of this element, we use the formula:

% mass = (mass of element / mass of ore) * 100%

% mass = (47.5 g / (660 kg * 1000 g / kg)) * 100*

8 0

3 years ago

Read 2 more answers

A graduated cylinder was filled to 20.3 mL with water. A solid object weighing 73.05 g was immersed in the water, raising the me

victus00 [196]

The density of the solid object will be 2.63 g/mL

<h3>What is density?</h3>

Density of objects = mass/volume.

Recall that an object will always displace its own volume when placed in a liquid.

Volume of the solid object = Cylinder reading after immersing the object in the water - cylinder reading before immersing the object in the water.

= 48.1 - 20.4

= 27.8 mL

Mass of the solid object = 73.05 g

Density of the object = 73.05/27.8

= 2.63 g/mL

More on density can be found here: brainly.com/question/15164682

#SPJ1

3 0

1 year ago

1. The pressure of a gas is 100.0 kPa and its volume is 500.0 ml. If the volume increases to 1,000.0 ml, what is the new pressur

marta [7]

Answer:

1) The new pressure of the gas is 500 kilopascals.

2) The final volume is 1.44 liters.

3) Volume will decrease by approximately 67 %.

4) The Boyle's Laws deals with pressures and volumes.

Explanation:

1) From the Equation of State for Ideal Gases we construct the following relationship:

$\frac{P_{2}}{P_{1}} = \frac{V_{1}}{V_{2}}$ (1)

Where:

$P_{1}, P_{2}$ - Initial and final pressure, measured in kPa.

$V_{1}, V_{2}$ - Initial and final pressure, measured in mililiters.

If we know that $P_{1} = 100\,kPa$ , $V_{1} = 500\,mL$ and $V_{2} = 1000\,mL$ , then the new pressure of the gas is:

$P_{2} = P_{1}\cdot \left(\frac{V_{1}}{V_{2}} \right)$

$P_{2} = 500\,kPa$

The new pressure of the gas is 500 kilopascals.

2) Let suppose that gas experiments an isothermal process. From the Equation of State for Ideal Gases we construct the following relationship:

$\frac{P_{2}}{P_{1}} = \frac{V_{1}}{V_{2}}$ (1)

Where:

$P_{1}, P_{2}$ - Initial and final pressure, measured in kPa.

$V_{1}, V_{2}$ - Initial and final pressure, measured in mililiters.

If we know that $V_{1} = 3.60\,L$ , $P_{1} = 10\,kPa$ and $P_{2} = 25\,kPa$ then the new volume of the gas is:

$V_{2} = V_{1}\cdot \left(\frac{P_{1}}{P_{2}} \right)$

$V_{2} = 1.44\,L$

The final volume is 1.44 liters.

3) From the Equation of State for Ideal Gases we construct the following relationship:

$\frac{P_{2}}{P_{1}} = \frac{V_{1}}{V_{2}}$ (1)

Where:

$P_{1}, P_{2}$ - Initial and final pressure, measured in kPa.

$V_{1}, V_{2}$ - Initial and final pressure, measured in mililiters.

If we know that $\frac{P_{2}}{P_{1}} = 3$ , then the volume ratio is:

$\frac{V_{1}}{V_{2}} = 3$

$\frac{V_{2}}{V_{1}} = \frac{1}{3}$

Volume will decrease by approximately 67 %.

4) The Boyle's Laws deals with pressures and volumes.

8 0

3 years ago

How is the periodic law demonstrated in halogens

inn [45]

Halogens is defined as the group of 7 periodic table. As, every periodic table contains 7 valence electrons and they only need 1 more to complete an outer shell, that is why they are extremely reactive. And according to the law that recurring patterns of the properties of elements arise when they are arranged in order of increasing atomic number. As the halogen all act very similarly with each other in chemical reaction, it is true.

3 0

3 years ago

Read 2 more answers

HELP ME ON THIS

diamong [38]

Answer:

The attractive force between them decreases

Explanation:

This is because they become localised.

7 0

3 years ago