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Irina-Kira [14]
2 years ago
12

How many moles are there in 15.0 grams of SiO2

Chemistry
2 answers:
earnstyle [38]2 years ago
8 0

Answer:

0.25 M

Explanation:

There is 60.0843 G of SiO2 per M making 15 g equal roughly 0.25

Vinvika [58]2 years ago
7 0

n(mole)=mass: MM(molar mass)

n = 15 : 60

n = 0.25

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Miss White wants to make a (decidedly not poisoned) apple pie. The recipe she is
Rina8888 [55]
So you have to multiply 786,3 times 0.98 to get the mass the mass is 770.57 if u round its 770.6 or 771
5 0
3 years ago
The first-order rearrangement of CH3NC is measured to have a rate constant of 3.61 x 10-15 s-1 at 298 K and a rate constant of 8
laiz [17]

Answer:

The correct answer is 160.37 KJ/mol.

Explanation:

To find the activation energy in the given case, there is a need to use the Arrhenius equation, which is,  

k = Ae^-Ea/RT

k1 = Ae^-Ea/RT1 and k2 = Ae^-Ea/RT2

k2/k1 = e^-Ea/R (1/T2-1/T1)

ln(k2/k1) = Ea/R (1/T1-1/T2)

The values of rate constant k1 and k2 are 3.61 * 10^-15 s^-1 and 8.66 * 10^-7 s^-1.  

The temperatures T1 and T2 are 298 K and 425 K respectively.  

Now by filling the values we get:  

ln (8.66*10^-7/3.61*10^-15) = Ea/R (1/298-1/425)

19.29 = Ea/R * 0.001

Ea = 160.37 KJ/mol

3 0
3 years ago
A substance made of two or more elements chemically combined in a set ratio, or proportion, is called a ___.
snow_lady [41]
Hey there!

The correct answer to your question is a compound.

A substance of two or more elements chemically combined in a set ratio, or proportion, is called a compound.
This is because compounds are made of two or more elements. Table salt is an example of a compound because it is made up of the elements chlorine and sodium.

Hope this helps you.
Have a great day!
7 0
3 years ago
if 28.5 g of calcium hydroxide is dissolved in enough water to make 185g of solution what is the percent by mass of calcium hydr
DENIUS [597]

The percent by mass of calcium hydroxide in the solution : 15.41%

<h3>Further explanation</h3>

The concentration of a substance can be expressed in several quantities such as moles, percent (%) weight/volume,), molarity, molality, parts per million (ppm) or mole fraction. The concentration shows the amount of solute in a unit of the amount of solvent.

Mass of solute (Ca(OH₂-Calcium hydroxide) : 28.5

Mass of solution = 185 g

\tt \%mass=\dfrac{mass~solute}{mass~solution}\times 100\%\\\\\%mass=\dfrac{28.5~g}{185~g}\times 100\%\\\\\%mass=15.41\%

6 0
3 years ago
Delocalization which occurs through overlap between stigma and p orbitals
elixir [45]

Answer:

Single covalent bonds that form between nuclei are created from the "head-to-head" overlap of orbitals and are called stigma (s) bonds. ... Another type of bond, a pi (p) bond is formed when two p orbitals overlap. Pi bonds are found in double and triple bond structures

Explanation:

Delocalization happens when electric charge is spread over more than one atom. For example, bonding electrons may be distributed among several atoms that are bonded together.

7 0
3 years ago
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