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4 years ago

What question can help u determine whether silver underwent is a chemical change or physical change

1 answer:

alexandr1967 [171]4 years ago

3 0

A question that can help you determine if silver underwent a chemical or psychic change is

1. is/has the substance changed? is it still the same or is it something completely new?
. if it is the same then its physical but if its not the same then its chemical.

.(ex:) if you cut up and paper into pieces then the substance hasn't changed because its still paper, just smaller xD this would be considered a psychic change.

.(ex:) if you burn a paper then the substance has change because its no longer paper/you can no longer write on it- this would be a chemical change.

another question would be

2. is it reversible? or not? (reversible- physical change) (not reversible - chemical change).

i hope that this kind of helps you.. xD sorry that its really long.

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HELP. NO FAKE ANSWERS. I WILL REPORT. I AM CONFUSED AND NEED HELP. FILL IN THE NOT FILLED BOXES POR FAVOR.

SCORPION-xisa [38]

Question #1
Potasium hydroxide (known)
volume used is 25 ml
Molarity (concentration) = 0.150 M
Moles of KOH used
0.150 × 25/1000 = 0.00375 moles
Sulfuric acid (H2SO4)
volume used = 15.0 ml
unknown concentration
The equation for the reaction is
2KOH (aq)+ H2SO4(aq) = K2SO4(aq) + 2H2O(l)
Thus, the Mole ratio of KOH to H2SO4 is 2:1
Therefore, moles of H2SO4 used will be;
0.00375 × 1/2 = 0.001875 moles
Acid (sulfuric acid) concentration
0.001875 moles × 1000/15
= 0.125 M

Question #2
Hydrogen bromide (acid)
Volume used = 30 ml
Concentration is 0.250 M
Moles of HBr used;
0.25 × 30/1000
= 0.0075 moles
Sodium Hydroxide (base)
Volume used 20 ml
Concentration (unknown)
The equation for the reaction is
NaOH + HBr = NaBr + H2O
The mole ratio of NaOH : HBr is 1 : 1
Therefore, moles of NaOH used;
= 0.0075 moles
NaOH concentration will be
= 0.0075 moles × 1000/20
= 0.375 M

7 0

3 years ago

Help me pleaseeee, ty if you doo:))

allochka39001 [22]

Answer:

9 is the correct answer

4 0

3 years ago

In the United States, volume of irrigation water is usually expressed in acre-feet. One acre-foot is a volume of water sufficien

gavmur [86]

Answer:

a) V = 1.542 E11 ft³

b) V = 4367011968 m³

c) V = 1.1535 E12 us gal

Explanation:

Acre surface is defined as 66 by 660 feet at a depth of one foot:

⇒ Vacre-foot = 66ft*660ft*1ft = 43560 ft³

lake:

a) V = 3.54 E6 acre-feet * ( 43560 ft³ / acre-foot ) = 1.542 E11 ft³

b) V = 1.542 E11 ft³ * ( 0.02832m³ / ft³ ) = 4367011968 m³

c) V = 1.542 E11 ft³ * ( 7.48052 us gal/ft³ ) = 1.1535 E12 us gal

6 0

4 years ago

What is the mass of 9 atom(s) of copper in grams?

il63 [147K]

9.05 E-22 g. ~ 10.0 E-22 g Cu

3 0

3 years ago

What is the molality of the resulting solution when 15.0 g of Licl is combined with 105 g of water? 0/1 point 0 1.42 m 2.95 m 3.

xenn [34]

Answer:

3.37 m

Explanation:

<u>Number of moles of solute present in 1 kg of solvent is termed as molality</u>

It is represented by 'm'.

Thus,

$Molality\ (m)=\frac {Moles\ of\ the\ solute}{Mass\ of\ the\ solvent\ (kg)}$

Given that:

The mass of LiCl = 15.0 g

Molar mass of LiCl = 42.394 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{15.0\ g}{42.394\ g/mol}$

$Moles= 0.3538\ mol$

Mass of the solvent = 105 g

Also, 1 g = 0.001 g

So,

Mass of water (solvent) = 0.105 kg

Molality is:

$Molality\ (m)=\frac {0.3538}{0.105}\ m$

<u>Molality = 3.37 m</u>

3 0

3 years ago