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3 years ago

Há extintores de incêndio que usam gás carbônico para apagar o fogo

Chemistry

1 answer:

kifflom [539]3 years ago

8 0

porque o gás carbônico afasta o oxigênio da parte que está em chamas, e não existe fogo sem oxigênio

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If the 3.90 m solution from Part A boils at 103.45 âC, what is the actual value of the van't Hoff factor, i? The boiling point o

poizon [28]

Answer:

Van't Hoff factor is 1.72 ≅ 2

Explanation:

Let's apply the colligative property of boiling point elevation:

ΔT = Kb . m . i

ΔT = Boiling T° of solution - T° boiling of pure solvent

103.45 °C - 100°C = 0.512 °C/m . 3.90 m . i

3.45 °C / 0.512 m/°C . 3.90 m = i

1.72 = i ≅ 2

7 0

3 years ago

Are the following instructions for diluting a 10.0 M solution to a 1.00 M solution correct: ""Take 100.0 mL of the 10.0 M soluti

Molodets [167]

The following directions for diluting a 10.0 M answer to a 1.00 M solution is no longer correct.

<h3>.What is the rule of dilution?</h3>

A popular rule to use in calculating the attention of solutions in a sequence is to multiply the unique concentration by means of the first dilution factor, this by the second dilution factor, this by the 1/3 dilution factor, and so on till the ultimate attention is known.

Example: A 5M answer of HCl is diluted 1/5.

<h3>How do you do a 1 in 10 dilution?</h3>

For example, to make a 1:10 dilution of a 1M NaCl solution, you would combine one "part" of the 1M solution with 9 "parts" of solvent (probably water), for a total of ten "parts." Therefore, 1:10 dilution ability 1 part + 9 components of water (or different diluent).

Learn more about dilution here:

<h3>brainly.com/question/25292980</h3><h3 /><h3>#SPJ4</h3>

7 0

2 years ago

A coffee-cup calorimeter contains 140.0 g of water at 25.1°C . A 124.0-g block of copper metal is heated to 100.4°C by putting i

Kisachek [45]

Answer:

(a) 3347 J; (b) 3043 J; (c) 58 J/K; (d) 35.5 °C

Explanation:

(a) Heat lost by copper

The formula for the heat lost or gained by a substance is

q =mCΔT

ΔT = T₂ - T₁= 30.3 °C - 100.4 °C = -70.1 °C = -70.1 K

q = 124.0 g × 0.385 J·K⁻¹g⁻¹ × (-70.1 K) = -3347 J

The negative sign shows that heat is lost.

The copper block has lost 3347 J.

(b) Heat gained by water

ΔT = 30.3 °C - 25.1 °C = 5.2 °C = 5.2 K

q = 140.0 g × 4.18 J·K⁻¹g⁻¹ × 5.2 K = 3043 J

The water has gained 3043 J.

(c) Heat capacity of calorimeter

Heat lost by Cu = heat gained by water + heat gained by calorimeter

The temperature change for the calorimeter is the same as that for the water.

ΔT = 5.2 K

$\begin{array}{rcl}\text{3347 J} & = & \text{3043 J} + C \times \text{5.2 K}\\\text{304 J} & = & 5.2C \text{ K}\\C & = & \dfrac{\text{304 J}}{\text{5.2 K}}\\\\& = & \text{58 J/K}\\\end{array}$

The heat capacity of the calorimeter is 58 J/K.

(d) Final temperature of water

$\begin{array}{rcl}\text{Heat lost by copper } + \text{Heat gained by water}& = &0 \\\text{Heat lost by copper}& = &-\text{Heat gained by water} \\m_{\text{Cu}}C_{\text{Cu}}\Delta T_{\text{Cu}}& = & -m_{\text{w}}C_{\text{w}}\Delta T_{\text{w}}\\\end{array}\\$

$\begin{array}{rcl}\text{124.0 g} \times \text{0.385 J$\cdot$K$^{-1}$g$^{-1}$}\times \Delta T_{\text{Cu}}& = & -\text{140.0 g} \times 4.18 \text{ J$\cdot$ K$^{-1}$g$^{-1}$}\times \Delta T_{\text{w}}\\\text{47.7 J$\cdot$K$^{-1}$}\times \Delta T_{\text{Cu}}& = &-\text{585 J$\cdot$ K$^{-1}$g}\times \Delta T_{\text{w}}\\\Delta T_{\text{Cu}} & = & -12.26\Delta T_{\text{w}}\\\end{array}$

$\begin{array}{rcl}\Delta T_{\text{f}} - 100.4 \, ^{\circ}\text{C} & = & -12.26(\Delta T_{\text{f}} - 30.3\, ^{\circ}\text{C})\\\Delta T_{\text{f}} - 100.4 \, ^{\circ}\text{C} & = & -12.26\Delta T_{\text{f}} + 371\, ^{\circ}\text{C}\\13.26\Delta T_{\text{f}} & = & 471\, ^{\circ}\text{C}\\\Delta T_{\text{f}} & = & 35.5\, ^{\circ}\text{C}\\\end{array}$

The final temperature of the water would be 35.5 °C.

7 0

3 years ago

Write a definition for each word and use each word in a sentence.<br> crystallization and organic

Artemon [7]

Answer:

Crystallization is the solidification of atoms or molecules into a highly structured form called a crystal.

Explanation:

Organic chemistry is the scientific study of the structure, properties, composition, reactions, and synthesis of organic compounds

3 0

3 years ago

What is the difference between covalent bonds and ions

Korvikt [17]

Ionic bonds have high emelting point amf boiling point while covale t bonds have low melting point and boiling point.
ionic bonds cannot conduct electricity in solid state but can conduct in the molten state or when dissolves in water. while covalent bonds cannot conduct electricity in any state.
ionic bonds are soluble in water but insoluble in organic solvents while most covalent bonds are soluble in organic solvents but insoluble in water

8 0

3 years ago