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Fudgin [204]
3 years ago
6

1. Which of the combinations in the lab activity had indications that a chemical change occured? Defend your argument with evide

nce.
2. Which of the combinations in the lab activity had indications that a physical change occured? Defend your argument with evidence.
3. Are all physical changes reversible? Explain your answer using an example you've observed in your everyday life.
4. Give an example of something you've observed in your everyday life that is a chemical reaction. How did you know it was a chemical reaction?
Chemistry
1 answer:
ArbitrLikvidat [17]3 years ago
4 0

Answer:The green growing on the penny of copper and the rust forming on the nail of iron are chemical changes. Boiling away salt water, scraping iron filings from a mixture of sand with a magnet, and breaking a rock with a hammer, are physical changes.

Explanation:

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What is the molarity of 0.26 mol of H2SO4 dissolved in 0.3 L of solution? *
irina1246 [14]

Answer:

A

Explanation:

molarity=moles of solute/liter of solution

molarity=0.26/0.3

molarity=0.87molar

7 0
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Separation of light into different wavelengths
TiliK225 [7]

Answer:

I'm sure it's Dispersion

Explanation:

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2 years ago
Which formula represents a saturated hydrocarbon
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Saturated hydrocarbons are organic compounds that contain only single bonds between the carbon atoms. They are known to be the simplest organic compounds. They are termed as such because they are saturated with water. Examples are the alkanes (ethane, methane, propane, butane, etc.).
6 0
3 years ago
5.(a) Give the names and symbols of respective elements. (5)
Leya [2.2K]

Answer:

Elements:

Platinum - Pt

Silicon - Si

Lead - Pb

Hydrogen- H

Silver - Ag

Symbols:

Pr - Praseodymium

K - Potassium

Br - Bromine

Mg - Magnesium

Hg - Mercury

6 0
1 year ago
A student who is performing this experiment pours an 8.50 mL sample of the saturated borax solution into a 10 mL graduated cylin
gtnhenbr [62]

Answer:

ksp = 0,176

Explanation:

The borax (Na₂borate) in water is in equilibrium, thus:

Na₂borate(s) ⇄ borate²⁻(aq) + 2Na⁺(aq)

<em>When you add just borax, the moles of Na²⁺ are twice the moles of borate²⁻, that means 2borate²⁻=Na⁺ </em><em>(1)</em>

The ksp is defined as:

<em>ksp = [borate²⁻] [Na⁺]²</em>

Then, borate²⁻(B₄O₇²⁻) reacts with HCl thus:

B₄O₇²⁻ + 2HCl + 5H₂O → 4H₃BO₃ + 2Cl⁻

The moles of HCl that reacts with B₄O₇²⁻ are:

0,500M×0,01200L = 6,00x10⁻³ mol of HCl

As two moles of HCl react with 1 mol of B₄O₇²⁻, the moles of B₄O₇²⁻ are:

6,00x10⁻³ mol of HCl×\frac{1molB_{4}O_{7}^{2-}}{2molHCl} = <em>3,00x10⁻³ mol of B₄O₇²⁻</em>

For (1), moles of Na⁺ are <em>3,00x10⁻³ mol ×2 = 6,00x10⁻³ mol of Na⁺</em>

The [borate²⁻] is <em>3,00x10⁻³ mol of B₄O₇²⁻/0,00850L = </em><em>0,353M</em>

And [Na⁺] is <em>6,00x10⁻³ mol of Na⁺ / 0,00850L = </em>0,706M

Replacing in the expression of ksp:

ksp = [0,353] [0,706]²

<em>ksp = 0,176</em>

<em></em>

I hope it helps!

8 0
2 years ago
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