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3 years ago

Please help!!

1 answer:

8 0

Molarity = Moles/Liter

Use the molecular atomic mass of NaCl to convert from grams to moles.
Molecular mass of NaCl is the sum of its atomic masses. Look at the periodic table to find these. Na is 23 g/mol and Cl is 35.5 g/mol ,
so NaCl = 23 + 35.5 = 58.5 g/mol

multiply to cancel out grams
76 g NaCl * (1mol / 58.5 g NaCl) = 1.3 mol NaCl

over 1 Liter is just 1.3 M NaCl
Hope this helps!

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6.0 g of copper was heated from 20 degree c to 90 degree c . How much energy was used to heat cu?

Darina [25.2K]

Copper heat capacity would be <span>0.385J/C*gram which means it needs 0.385 Joule of energy to increase 1 gram of copper temperature by 1 Celcius. The calculation would be:
energy= heat capacity *mass * temperature difference
energy= </span>0.385J/C*gram * 6g * (90-20)
<span>energy= 161.7J
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4 0

3 years ago

Mass

DiKsa [7]

The molecular formula =C₆H₁₂O₆

<h3>Further explanation</h3>

Given

6.00 g of a certain compound X

The molecular molar mass of 180. g/mol

CO₂=8.8 g

H₂O=3.6 g

Required

The molecular formula

Solution

mass C in CO₂ :

= 1.12/44 x 8.8

= 2.4 g

mass H in H₂O :

= 2.1/18 x 3.6

= 0.4 g

Mass O in compound :

= 6-(2.4+0.4)

= 3.2 g

Mol ratio C : H : O

= 2.4/12 : 0.4/1 : 3.2/16

= 0.2 : 0.4 : 0.2

= 1 : 2 : 1

The empirical formula : CH₂O

(CH₂O)n=180 g/mol

(12+2+16)n=180

(30)n=180

n=6

(CH₂O)₆=C₆H₁₂O₆

7 0

3 years ago

Calculate the mass of Na2O that can be produced by the chemical reaction of 4.0 grams of sodium with excess oxygen in the reacti

e-lub [12.9K]

Answer:

The mass of Na₂O that can be produced by the chemical reaction of 4.0 grams of sodium with excess oxygen in the reaction is 5.39 grams.

Explanation:

You know the balanced reaction:

4 NA + O₂ ⟶ 2 Na₂O

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction) react and are produced:

Na: 4 moles
O₂: 1 mole
Na₂O: 2 moles

Being:

Na: 23 g/ole
O: 16 g/mole

the molar mass of the compounds participating in the reaction is:

Na: 23 g/mole
O₂: 2*16 g/mole= 32 g/mole
Na₂O: 2*23 g/mole +16 g/mole= 62 g/mole

Then by stoichiometry of the reaction they react and are produced:

Na: 4 moles* 23 g/mole= 92 g
O₂: 1 mole*32 g/mole= 32 g
Na₂O: 2 moles* 62 g/mole= 124 g

Then you can apply the following rule of three: if 92 grams of Na produce 124 grams of Na₂O, 4 grams of Na, how much mass of Na₂O does it produce?

$massofNa_{2}O =\frac{4 grams of Na*124 gramsofNa_{2}O }{92 grams of Na}$

mass of Na₂O=5.39 g

<em><u>The mass of Na₂O that can be produced by the chemical reaction of 4.0 grams of sodium with excess oxygen in the reaction is 5.39 grams.</u></em>

8 0

3 years ago

Density is the ratio of a sample's mass to its volume. A bar of lead has a mass of 115.2 g. When it is submerged in 25.0 mL of w

Margarita [4]

Answer:

$10.97 \ g/cm^3$