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3 years ago

Express in scientific notation. Choose the answer with the proper number of significant figures.

Chemistry

1 answer:

bazaltina [42]3 years ago

3 0

Answer:

4.5 times 10 = 45

Explanation:

"Non-zero digits are always significant. Any zeros between two significant digits are significant. A final zero or trailing zeros in the decimal portion ONLY are significant."

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What is the predominant intermolecular force in CBr4

vovikov84 [41]

CBr4 is a symmetric tetrahedral molecule so it will be non-polar.

3 0

3 years ago

If I had 3.50 x 10 24molecules of Cl2 gas, how many grams is this?

Zinaida [17]

Answer:

412 g Cl₂

General Formulas and Concepts:

Atomic Structure

Reading a Periodic Table
Moles
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Stoichiometry

Using Dimensional Analysis

Explanation:

Step 1: Define

[Given] 3.50 × 10²⁴ molecules Cl₂

[Solve] grams Cl₂

Step 2: Identify Conversions

Avogadro's Number

[PT] Molar Mass of Cl - 35.45 g/mol

Molar Mass of Cl₂ - 2(35.45) = 70.9 g/mol

Step 3: Convert

[DA] Set up: $\displaystyle 3.50 \cdot 10^{24} \ molecules \ Cl_2(\frac{1 \ mol \ Cl_2}{6.022 \cdot 10^{23} \ molecules \ Cl_2})(\frac{70.9 \ g \ Cl_2}{1 \ mol \ Cl_2})$
[DA] Divide/Multiply [Cancel out units]: $\displaystyle 412.072 \ g \ Cl_2$

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

412.072 g Cl₂ ≈ 412 g Cl₂

5 0

3 years ago

What is the pH of 0.30 M ethanolamine, HOCH2CH2NH2, (Kb = 3.2 x 10−5)?

Dmitry [639]

Answer:

pH= 11.49

Explanation:

Ethanolamine is an organic chemical compound of the formula; HOCH2CH2NH2. Ethanolamine, HOCH2CH2NH2 is a weak base.

From the question, the parameters given are; the concentration of ethanolamine which is = 0.30M, pH value= ??, pOH value= ??, kb=3.2 ×10^-5

Using the formula below;

[OH^-]=√(kb×molarity)----------------------------------------------------------------------------------------------------------(1)

[OH^-] =√(3.2×10^-5 × 0.30M)

[OH^-]= √(9.6×10^-6)

[OH^-]=3.0984×10^-3

pOH= -log[OH^-]

pOH= -log 3.1×10^-3

pOH= 3-log 3.1

pH= 14-pOH

pH= 14-(3-log3.1)

pH= 11+log 3.1

pH= 11+ 0.4914

pH= 11.49

8 0

3 years ago

The acidity of normal rain water is due to ______. a) SO2 b) CO2 c) NO2 d) NO

Viktor [21]

The correct answer choice is CO₂ (B)

Rainwater naturally contains acids derived from carbon dioxide in the air and reacts with water vapor to form weak acids

H₂O + CO₂ ---> H₂CO₃

<h3>Further Explanation</h3>

Rainwater can cause damage to buildings, animals or plants due to acid rain

Acid rain occurs because other gases in the air mix with toxic gases to form acids

Rainwater naturally contains acids derived from carbon dioxide in the air and reacts with water vapor to form weak acids

H₂O + CO₂ ---> H₂CO₃

However, due to exhaust gases from industry, motor vehicles, or power plants that use fossil fuels containing sulfur to produce sulfur dioxide gas which will produce sulfuric acid

Sulfur combustion from fossil fuels

S + O₂ ----> SO₂

SO₂ produced from this exhaust gas reacts with O₂ oxygen which oxidizes SO₂ to SO₃

SO₂ + O₂ ----> SO₃

SO3 formed reacts with water vapor in the air to produce sulfuric acid as acid rain

SO₃ + H₂O ---> H₂SO₄

To reduce the pollution from this fossil fuel, various studies are now carried out as substitute energy that is more environmentally friendly such as solar energy and so on

<h3>Learn more </h3>

Acid rain is a secondary pollutant

brainly.com/question/1324440

The impact of from acid rain

brainly.com/question/8208861

Air pollution

brainly.com/question/1232950

Keywords: acid rain, air pollution, SO₃, H₂SO₄, fossil fuel