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yulyashka [42]
3 years ago
14

For a laboratory investigation some students put a strip of shiny metal into a beaker of blue solution and then stored the beake

r on a shelf
overnight. The next morning, the students recorded observations about the metal and the solution in the box below.
Students' Observations
Exhibit
. The solution is lighter in color,
The volume of solution is the same.
• The metal strip is shiny above the surface of the solution
• The metal strip is not shiny below the surface of the solution.
• The metal strip below the surface of the solution has a dark
coat of flaky material
• When the metal strip is touched, the flaky material falls off.
Based on their observations, can the students correctly conclude that a chemical reaction occurred?
A. No, because the metal strip was still visible
B. Yes, because a new material of a different color formed on part of the metal strip
c. No, because the solution stayed blue
ble solution stayed the same
12 AM

Chemistry
1 answer:
KatRina [158]3 years ago
8 0

Answer:

b

Explanation:

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7 0
3 years ago
Read 2 more answers
Calculate the number of moles<br> 41.0 g of Ca(NO3)2 <br> 1.48 g of Ca(OH)2 <br> 3.40 g of CaSO4
Lemur [1.5K]
First. moles is just a label for a number of things. just like a dozen = 12, a gross = 144, a mole = 6022 with another 20 zeros after the 2

next

moles = mass / molecular weight.

molecular weight = sum of atomic mass from the periodic table

atomic mass MnO2 = atomic mass Mn + 2 x atomic mass O
= 54.94 + 2 x 16 = 86.94 g/mole

so moles MnO2 = 98.0 grams / (86.94 g/mole) = 1.13 moles

notice that I only gave 3 digits? that because of sig figs read the link below if you don't understand....

mw C5H12 = 5 x 12 + 12 x 1 = 72 g/mole

so moles C5H12 = 12.0 g / 72.0 g/mole = 0.167 moles

mw XeF6 = 131.3+ 6 x 19.00 = 245.3

so moles XeF6 = 100 g / 245.3 g/mole = 0.4077 moles

I've also provided a link to a periodic table. if you need atomic weights click on any element and it will give you the
details.
8 0
3 years ago
Please help me please it's urgent​
alisha [4.7K]

Answer:

<h2>Paraphrase this! I got this online!</h2>

1.A a Chemical Reaction is a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.

1.A Chemical reactions involve breaking chemical bonds between reactant molecules (particles) and forming new bonds between atoms in product particles (molecules)

1A.Chemical bonding, any of the interactions that account for the association of atoms into molecules, ions, crystals, and other stable species that make up the familiar substances of the everyday world.

2a.A gas evolution reaction is a chemical reaction in which one of the end products is a gas such as oxygen or carbon dioxide. Gas evolution reactions may be carried out in a fume chamber when the gases produced are poisonous when inhaled or explosive.

2b.a color change is usually an indicator that a reaction is occurring

2c.Processes involved in changes of state include melting, freezing, sublimation, deposition, condensation, and evaporation

3A.When you increase the pressure, the molecules have less space in which they can move. That greater density of molecules increases the number of collisions

3B.As an object gets hot, its atoms and molecules vibrate. As they vibrate, they release energy in the form of light. ... In chemiluminescence, energy from a chemical reaction excites the electrons of a substance

3C. Catalysis is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst. Catalysts are not consumed in the reaction and remain unchanged after it.

3D.Most chemical reactions involve the breaking and formation of chemical bonds. It takes energy to break a chemical bond but energy is released when chemical bonds are formed. If more energy is released than consumed, then the chemical reaction evolves heat and is said to be exothermic. ... Most reactions are exothermic.

<h2>Paraphrase this! I got this online!</h2><h2>Paraphrase this! I got this online!</h2><h2>Paraphrase this! I got this online!</h2>
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