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3 years ago

Which statement best describes the work and energy in these examples?

Chemistry

1 answer:

kari74 [83]3 years ago

3 0

Answer:

The gas and food are examples of energy.

Explanation:

The reason why is that food is energy as proteins and electrolytes. Gas is a energy of fossil fuels.

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How would I put this into words C2H7OH + O2 ---> CO2 + H2O

anastassius [24]

Answer:

My Understanding:

Explanation:

2 Carbon, 7 Hydrogen, 1 Oxygen, 1 Hydrogen plus 2 Oxygen is the reactants of 1 Carbon, 2 Oxygen plus 2 Hydrogen, and 1 Oxygen.

3 0

3 years ago

1. Calculate how many moles of glycine are in a 130.0-g sample of glycine.2. Calculate the percent nitrogen by mass in glycine.

Alexxx [7]

Answer:

$n=1.732mol$

$\% N=18.7\%$

Explanation:

Hello!

In this case, since the molecular formula of glycine is C₂H₅NO₂, we realize that the molar mass is 75.07 g/mol; thus, the moles in 130.0 g of glycine are:

$n=130.0g*\frac{1mol}{75.07 g}\\\\ n=1.732mol$

Furthermore, we can notice 75.07 grams of glycine contains 14.01 grams of nitrogen; thus, the percent nitrogen turns out:

$\% N=\frac{14.01}{75.07}*100\% \\\\\% N=18.7\%$

Best regards!

4 0

3 years ago

A___________ consists of a mixture of graphite powder (a form of carbon) and clay that is baked and hardened and encased in wood

Harlamova29_29 [7]

Answer:

A_____PENCIL______ consists of a mixture of graphite powder (a form of carbon) and clay that is baked and hardened and encased in wood or paper. a. silverpoint b. pencil c. charcoal d. chalk e. paste

Explanation:

A pencil is a writing material, where the graphite is what gives the black color to the writing stroke.

5 0

3 years ago

Na+CL2=2NACL is the balanced reaction for the formation of table salt. Given 20 grams of Na and 10 grams of Cl2, which reactant

Elina [12.6K]

Excess reactant : Na

NaCl produced : = 16.497 g

<h3>Further explanation</h3>

Given

Reaction(balanced)

2Na + Cl₂⇒ 2NaCl

20 g Na

10 g Cl₂

Required

Excess reactant

NaCl produced

Solution

mol Na(Ar = 23 g/mol) :

= 20 : 23 = 0.87

mol Cl₂(MW=71 g/mol):

= 10 : 71 g/mol = 0.141

mol : coefficient :

Na = 0.87 : 2 = 0.435

Cl₂ = 0.141 : 1 = 0.141

Limiting reactant : Cl₂(smaller ratio)

Excess reactant : Na

Mol NaCl based on mol Cl₂, so mol NaCl :

= 2/1 x mol Cl₂

= 2/1 x 0.141

= 0.282

Mass NaCl :

= 0.282 x 58.5 g/mol

= 16.497 g

4 0

3 years ago

What is the difference in mass between 3.01×10^24 atoms of gold and a gold bar with the dimensions 6.00 cm X 4.25 cm X 2.00 cm

Zanzabum

Answer:

The difference in mass between 3.01×10^24 atoms of gold and a gold bar with the dimensions 6.00 cm X 4.25 cm X 2.00 cm is :

Difference in mass = 985.32 - 984.5 = 0.82 g

Explanation:

Part I :

$n =\frac{3.01\times 10^{24}}{6.022\times 10^{23}}$

n = 4.9983

n = 4.99 moles

(Note : You can also take n = 5 mole )

Molar mass of gold = 196.96 g/mole

This means, 1 mole of gold(Au) contain = 196.96 grams

So, 4.99 moles of gold contain = $5\times 196.96$ g

4.99 moles of gold contain = 984.8 g

Mass of ${3.01\times 10^{24}}$ atoms of gold = 984.5 g

Part II :

Density of Gold = $19.32 g/cm^{3}$

Volume of the cuboid = $length\times breadth\times height$

Volume of the gold bar = $6.00\times 4.25\times 2.00$

Volume of the gold bar = 51 $cm^{3}$

Using formula,

$Density = \frac{mass}{Volume}$

$Mass = Density\times Volume$

$Mass = 19.32 \times 51$

Mass = 985.32 g

So, A gold bar with the dimensions 6.00 cm X 4.25 cm X 2.00 cm has mass of 985.32 g

Difference in mass = 985.32 - 984.5 = 0.82 g

3 0

3 years ago