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Maru [420]
2 years ago
5

I NEED TOUR HELP, PLEASE.

Chemistry
1 answer:
kvasek [131]2 years ago
8 0
It would be 5.0 more in i did this
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What is the mass of 4.99×1021 platinum atoms?
charle [14.2K]

Answer:

\boxed {\boxed {\sf 1.62 \ g \ Pt}}

Explanation:

We are asked to find the mass of a number of platinum (Pt) atoms.

<h3>1. Convert Atoms to Moles </h3>

First, we convert atoms to moles using 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 platinum atoms.

We will convert using dimensional analysis so we set up a ratio using the information we know (6.022 × 10²³ platinum atoms in 1 mole of platinum).

\frac {6.022 \times 10^{23} \ atoms \ Pt}{ 1 \ mol \ Pt}

We are converting 4.99 ×10²¹ atoms of Pt to moles of Pt, so we multiply by this value.

4.99 \times 10^{21} \ atoms \ Pt *\frac {6.022 \times 10^{23} \ atoms \ Pt}{ 1 \ mol \ Pt}

Flip the ratio so the units of atoms of platinum cancel.

4.99 \times 10^{21} \ atoms \ Pt *\frac { 1 \ mol \ Pt}{6.022 \times 10^{23} \ atoms \ Pt}

4.99 \times 10^{21} *\frac { 1 \ mol \ Pt}{6.022 \times 10^{23}}

\frac { 4.99 \times 10^{21}}{6.022 \times 10^{23}} \ mol \ Pt

Divide.

0.008286283627 \ mol \ Pt

<h3>2. Convert Moles to Grams </h3>

Next, we convert moles to grams using the molar mass. This is the mass of 1 mole of a substance. This is found on the Periodic Table because it is equivalent to the atomic mass, but the units are grams per mole instead of atomic mass units. Look up platinum's molar mass.

  • Pt: 195.08 g/mol

Set up another ratio using this new information (195.08 grams of Pt in 1 mole of Pt).

\frac {195.08 \ g \ Pt}{ 1 \ mol \ Pt}

Multiply by the number of moles we just calculated.

0.008286283627 \ mol \ Pt*\frac {195.08 \ g \ Pt}{ 1 \ mol \ Pt}

The units of moles of platinum cancel.

0.008286283627*\frac {195.08 \ g \ Pt}{ 1 }

0.008286283627* {195.08 \ g \ Pt}

1.61648821\ g \ Pt

<h3>3. Round</h3>

The original measurement of atoms ( 4.99 ×10²¹ ) has 3 significant figures, so our answer must have the same. For the number we found, that is the hundredth place. The 6 in the thousandth place tells us to round the 1 up to a 2.

1.62 \ g \ Pt

There are approximately <u>1.62 grams of platinum</u> in 4.99 ×10²¹ atoms of platinum.

8 0
3 years ago
Which formula correctly represents the product of an addition reaction between ethene and chlorine?
Serjik [45]
The formula that correctly represents the product of an addition reaction between ethene and chlorine is  C2H4Cl2
Addition reaction occurs when an atom is added to a compound that has a double bond or triple bond (unsaturated hydrocarbons). Unsaturated compounds are associated with addition reactions. For example Ethene is an example of unsaturated hydrocarbon; when reacted with chlorine gas , chlorine atoms are added to each carbon atoms. 
4 0
3 years ago
PLEASE HELP <br> C. Balance these fossil-fuel combustion reactions. (1 point)
Damm [24]

Answer:

C8H18(g) + 12.5O2(g) -> __8__CO2(g) + 9H2O(g) + heat

CH4(g) + _2___O2(g) -> ____CO2(g) + _2___H2O(g) + heat

C3H8(g) + _5___O2(g) -> _3___CO2(g) + __4__H2O(g) + heat

2C6H6(g) + __15__O2(g) ->  __12__CO2(g) + __6__H2O(g) + heat

Explanation:

I hope it helps!

7 0
3 years ago
Which substance can be broken down by chemical means?
sp2606 [1]
The substance that can be broken down by chemical means from the choices given is CO (Carbon monoxide). Carbon monoxide is a compound made up of carbon and oxygen and can therefore be broken by chemical means.
7 0
3 years ago
ASAP PLEASE HELP ASAP
Salsk061 [2.6K]

swift to hear, slow to speak

Explanation:

7 0
3 years ago
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