What methods do scientists use to determine if a change was physical or chemical?

1 answer:

5 0

A physical change will not change the chemical make-up of the material. the change will not produce a new substance.

a chemical change will have a reaction that produces heat, light, a change in color, releases a gas, or rust

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In a chemical reaction, the products are

Blizzard [7]

whatever u r mixing together will indicated what the reaction or the product will be

6 0

3 years ago

Read 2 more answers

A flashbulb of volume 2.70 mL contains O2(g) at a pressure of 2.30 atm and a temperature of 30.0 °C. How many grams of O2(g) doe

Sholpan [36]

P = 2.30 atm

Volume in liter = 2.70 mL / 1000 => 0.0027 L

Temperature in K = 30.0 + 273 => 303 K

R = 0.082 atm

molar mass O2 = 31.9988 g/mol

number of moles O2 :

P * V = n * R* T

2.30 * 0.0027 = n * 0.082 * 303

0.00621 = n * 24.846

n = 0.00621 / 24.846

n = 0.0002499 moles of O2

Mass of O2:

n = m / mm

0.0002499 = m / 31.9988

m = 0.0002499 * 31.9988

m = 0.008 g

3 0

3 years ago

7.66 Write balanced equations for the following reactions: (a) potassium oxide with water, (b) diphosphorus trioxide with water,

White raven [17]

Explanation:

(a) potassium oxide with water

$K_2O(s)+H_2O(l)\rightarrow 2KOH(aq)$

According to reaction,1 mole of potassium oxide reacts with 1 mole of water to give 1 mole of potassium hydroxide.

(b) diphosphorus trioxide with water

$P_2O_3(s)+3H_2O(l)\rightarrow 2H_3PO_3(aq)$

According to reaction,1 mole of diphosphorus trioxide reacts with 2 moles of water to give 2 moles of phosphorus acid.

(c) chromium(III) oxide with dilute hydrochloric acid,

$Cr_2O_3(s)+6HCl(aq)\rightarrow 2CrCl_3(aq)+3H_2O(l)$

According to reaction,1 mole of chromium(III) oxide reacts with 6 moles of hydrochloric acid to give 2 moles of chromium(III) chloride and 3 moles of water.

(d) selenium dioxide with aqueous potassium hydroxide

$SeO_2 (s)+2KOH (aq)\rightarrow K_2SeO_3(aq)+H_2O(l)$