Chemistry, 18.04.2021 01:10 zachcochran2007

What is the mass of 1.5 x 10^21 silicon atoms?

Answers: 3

Show answers

Answers

Answer from: clairajogriggsk

$\boxed {\boxed {\sf 0.070 \ g \ Si}}$

Explanation:

We are given a value of atoms and asked to find the mass. We can complete this in 2 steps.

1. Convert Atoms to Moles

First, we have to convert atoms to moles. We use Avogadro's Number or 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance.

In this case, the particles are silicon atoms. We can set up a proportion.

$\frac { 6.022 \times 10^{23} \ atom \ Si }{1 \ mol \ Si}$

Multiply by the value of atoms given.

$1.5 \times 10^{21} \ atom \ Si *\frac { 6.022 \times 10^{23} \ atom \ Si }{1 \ mol \ Si}$

Flip the ratio. This allows the atoms of silicon units to cancel and leave the moles of silicon.

$1.5 \times 10^{21} \ atom \ Si *\frac {1 \ mol \ Si } {6.022 \times 10^{23} \ atom \ Si}$

$1.5 \times 10^{21}*\frac {1 \ mol \ Si } {6.022 \times 10^{23} }$

$\frac {1.5 \times 10^{21} \ mol \ Si } {6.022 \times 10^{23} }$

$0.002490866822 \ mol \ Si$

2. Convert Moles to Grams

Next, we convert the moles to grams. We use the molar mass, which is found on the Periodic Table. This value is the number of grams in 1 mole of a substance. Look for silicon (Si).

Si: 28.085 g/mol

Use this value as a ratio.

$\frac {28.085 \ g \ Si}{1 \ mol \ Si}$

Multiply by the number of moles we calculated.

$0.002490866822 \ mol \ Si *\frac {28.085 \ g \ Si}{1 \ mol \ Si}$

The moles of silicon units cancel, so we are left with grams.

$0.002490866822 *\frac {28.085 \ g \ Si}{1}$

$0.002490866822 *{28.085 \ g \ Si}$

$0.06995599469 \ g \ Si$

3. Round

Finally we must round our answer. The original value has 2 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place.

$0.069\underline95599469 \ g Si$

The 9 tells us to round the other 9 to a 0, then the 6 to a 7.

$0.070 \ g \ Si$

The mass of 1.5 × 10²¹ silicon atoms is 0.070 grams of silicon.

Answer from: Quest

b is the correct

Answer from: Quest

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.

Another question on Chemistry

Chemistry, 22.06.2019 03:10

Describe the difference between a. a hypothesis and a theory and b. an observation and an experiment.

Answers: 1

Answer

Chemistry, 22.06.2019 08:00

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.

Answers: 2

Answer

Chemistry, 22.06.2019 09:30

Which ocean zone has the most abundant primary producer and why a) the abyssopelagic zone ,du to the absence of light and cold water temperatureb) the bathypelagic zone, due to the absence of light and cold water temperaturec) the mesopelagic zone ,due to uts high light availability and warm water temperature d) the epipelagic zone,due to its high light availability and warm water temperature

Answers: 3

Answer

Chemistry, 23.06.2019 04:31

Pls i will do pls imma diewhat forms white light? (4 points)a. combination of all wavelengths of ultraviolet light b. combination of all wavelengths of visible lightc. absorption of electromagnetic waves d. absorption of infrared rays