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2 years ago

9

Which events represents a chemical change ?

2 answers:

8_murik_8 [283]2 years ago

5 0

D milk turning sour
the other options are physical changes

yawa3891 [41]2 years ago

3 0

Hihi!

The answer would be D. milk turning sour! What happens when milk goes sour is it<span> ferment lactose at room temperature and which turns it into lactic acid. More acid means more hydrogen ions, a lower pH and a </span>sour<span> taste. Lower pH change the structure of proteins like casein, which gives </span>milk<span> its whiteness, so it curdles into clumps called curds! It's pretty gross!</span>

I hope I helped!
-Jailbaitasmr

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Most water on earth is in which form

dem82 [27]

Liquid, because of all the oceans and seas.

4 0

3 years ago

Read 2 more answers

A certain first-order reaction has a rate constant of 2.75 10-2 s−1 at 20.°c. what is the value of k at 45°c if ea = 75.5 kj/mol

Gekata [30.6K]

Answer:

0.314 s⁻¹

Step-by-step explanation:

Use the <em>Arrhenius equation.</em>

$\ln( \frac{k_2 }{k_1 }) = (\frac{E_{a} }{R })(\frac{ 1}{T_1} - \frac{1 }{T_2 })\\$

Data:

k₁ = 0.0275 s⁻¹; k₂ = ?

Eₐ = 75.5 kJ·mol⁻¹

T₁ = 20 °C = 293.15 K; T₂ = 45°C = 318.15 K

<em>Calculation: </em>

$\ln(\frac{k_{2} }{0.0275}) = (\frac{75 500 }{8.314})(\frac{ 1}{293.15} - \frac{1 }{318.15 })$

$\ln(\frac{k_{2} }{0.0275}) = 9081\times 2.681 \times10^{-4}$

$\ln(\frac{k_{2} }{0.0275}) = 2.434$

$\frac{k_{2} }{0.0275} = \text{e}^{2.434}$

$\frac{k_{2} }{0.0275} = 11.41$

k₂ = 0.0275 × 11.41

k₂ = 0.314 s⁻¹

3 0

3 years ago

The main difference between gases and liquids is that in gases A.the molecules are moving faster b.the forces between molecules

mestny [16]

I believe the answer would be A

3 0

2 years ago

When 45.8 g of K2CO3 react with excess HCI, 46.3 g of KCl are formed. Calculate the theoretical and % yields of

Talja [164]

Answer:

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7 0

2 years ago

The observed rotation of 2.0 gg of a compound in 50 mLmL of solution in a polarimeter tube 25-cmcm long is +47.2 ∘∘ . What is th

Anastaziya [24]

Answer:

[∝] = +472

Explanation:

Specific rotation in a solution is defined as:

[∝] = ∝ / c×l

Where:

[∝] is specific rotation, ∝ is observed rotation (In degrees), c is concentration in g/mL and l is path length (In dm).

∝: +47.2°

c: 2.0g / 50mL = 0.04g/mL

l: 25cm × (1dm /10cm) = 2.5dm

Replacing:

[∝] = +47.2° / 0.04g/mL×2.5dm = <em>+472</em>

I hope it helps!

4 0

3 years ago