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3 years ago

Which of the following is a sign a chemical reaction has occurred?

Chemistry

2 answers:

tankabanditka [31]3 years ago

6 0

A solid dissolves in abolishing forms from the mixing of 2 liquids

dimulka [17.4K]3 years ago

6 0

Answer: A solid forms when two liquids are mixed.

Explanation:

A physical reaction is defined as the reaction in which a change in shape, size takes place. No new substance gets formed in these reactions.

A chemical reaction is defined as the reaction in which a change in chemical composition takes place. A new substance is formed in these reactions.

1. A solid dissolves in liquid: Only the phase of the solid changes to aqueous and no new substance is formed, thus is a physical change.

2. A solid forms when two liquids are mixed: two liquids can forma solid only on chemical combination and formation of new substance.

3. A solid melts to a liquid when it is heated: Only the phase of the solid changes to liquid, no new substance is formed, thus is a physical change.

4. A solid metal changes shape: Only the shape of the solid changes, thus is a physical change.

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Balance the following: ___ AlBr3+ ___ K---> ___KBr+ ___ Al

Nataliya [291]

___AlBr3 + ___K -> ___KBr + ___ Al

1 AlBr3 + 3K -> 3KBr + 1 Al

hope this helps............

6 0

3 years ago

For the titration of 25.00 mL of 0.150 M HCl with 0.250 M NaOH, calculate:

Leviafan [203]

1) Chemical reaction

HCl        +       NaOH      --->      NaCl + H2O

25.0 ml
0.150 M            0.250M

2) 50% completion => 0.025 l * 0.150 M * (1/2) = 0.001875 mol HCl consumed and 0.001875 mol HCl in solution

0.001875 mol HCl => 0.001875 mol H(+)

Volume = Volume of HCl solution + Volumen of NaOH solution added

Volume of HCl solution = 0.0250 l

Volume of NaOH = n / M = 0.001875 mol / 0.250M = 0.0075 l

Total volume = 0.0250 l + 0.0075 l = 0.0325 l

[H+] = 0.001875 mol / 0.0325 l = 0.05769 M

pH = - log [H+] = - log (0.05769) = 1.23

Answer: 1.23

3) Equivalence point

0.02500 l * 0.150 M = 0.250M * V

=> V = 0.02500 * 0.150 / 0.250 = 0.015 l

4) 1.00 ml NaOH added beyond the equivalence point

1.00 ml * 1 l / 1000 ml * 0.250 M = 0.00025 mol NaOH in excess

0.00025 mol NaOH = 0.00025 mol OH-

Volume of the solution = 0.02500 l + 0.015 l + 1.00/1000 l = 0.041 l

[OH-] = 0.00025 mol / 0.041 l = 0.00610 M

pOH = - log (0.00610) = 2.21

pH + pOH = 14 => pH = 14 - pOH = 14 - 2.21 = 11.76

Answer: 11.76

6 0

3 years ago

Select the keyword or phrase that will best complete each sentence. A tetrahedral carbon is____hybridized while a linear carbon

aivan3 [116]

Answer:

Explanation:

A tetrahedral carbon is__sp³__hybridized while a linear carbon is__sp___hybridized. Two different compounds that have the same molecular formula are known as___isomers____. Pi (π) bonds are generally_weaker (because they overlapped side ways)___than sigma (sigma) bonds. Hybridization is the combination of two or more__atomic ____orbitals to form the same number of__hybrid (combined s and p)__orbitals, each having the same shape and energy. A_pi (π)____bond is formed by side-by-side overlap of two p orbitals. The_electronegativity___is a measure of an atom's attraction for electrons in a bond and indicates how much a particular atom ''wants" electrons. Two Lewis structures that have the same atomic placement and a structure but a different arrangement of pi electrons are called_Resonance structure____. All single bonds are___sigma__bonds.

7 0

3 years ago

A scuba diver that ascends to the surface too quickly can experience decompression sickness, which occurs when nitrogen that dis

Butoxors [25]

Answer:

The factor that will change the volume of the diver's lungs upon reaching the surface is 4

Explanation:

Given data:

Pressure increases 1 atm = 101.325 kPa

34 ft = 10.3632 m

Depth of 102 ft = 31.0896 m

Question: What factor will the volume of the diver's lungs change upon arrival at the surface, V₂/V₁ = ?

The pressure at 31.0896 m:

$P_{1} =101.325+(\frac{31.0896}{10.3632} *101.325)=405.3kPa$

The factor will the volume of the diver's lungs change upon arrival at the surface:

$\frac{V_{2}}{V_{1} } =\frac{P_{1}}{P_{2}} =\frac{405.3}{101.325} =4$

5 0

3 years ago

Using mathematical expressions drive the compression factor

Zarrin [17]

Answer:

just look it up yourself

Explanation:

ITS NOT THAT HARD

6 0

3 years ago