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2 years ago

PLEASE HELP!! THREE QUESTIONS AND 30 points + brainliest!!!!!

Chemistry

1 answer:

tekilochka [14]2 years ago

8 0

1. Last Answer Choice
2. I am not sure
3. 183/310=90/150 so the answer is 150 mm Hg

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Which characteristic do valence electrons indicate about reactions between atoms?

Setler [38]

Bond number

The characteristic of reactions that depends on valence electrons is the bond type.

In chemistry, a chemical bond could be;

Ionic

Covalent

The type of bond formed depends on the number of valence electrons present. When there are few valence electrons on an atom, it mostly forms ionic bonds.

When there are more electrons on an atoms, it mostly forms covalent bonds and the electrons between the atoms are shared.

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2 years ago

A hot gas flowing through a pipeline can be considered as a:________

k0ka [10]

Answer:

B) irreversible process

Explanation:

The process given here is irreversible.

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2 years ago

replacing standard incandescent lightbulbs with energy-efficient compact fluorescent lightbulbs can save a lot of energy. Calcul

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2 years ago

When 125 mL of 0.150 M Pb(NO3)2 is mixed with 145 mL of 0.200 M KBr, 4.92 g of PbBr2 is collected. Calculate the percent yield.

Semenov [28]

Answer:

Y = 92.5 %

Explanation:

Hello there!

In this case, since the reaction between lead (II) nitrate and potassium bromide is:

$Pb(NO_3)_2+2KBr\rightarrow PbBr_2+2KNO_3$

Exhibits a 1:2 mole ratio of the former to the later, we can calculate the moles of lead (II) bromide product to figure out the limiting reactant:

$0.125L*0.150\frac{molPb(NO_3)_2}{L} *\frac{1molPbBr_2}{1molPb(NO_3)_2} =0.01875molPbBr_2\\\\0.145L*0.200\frac{molKBr}{L} *\frac{1molPbBr_2}{2molKBr} =0.0145molPbBr_2$

Thus, the limiting reactant is the KBr as it yields the fewest moles of PbBr2 product. Afterwards, we calculate the mass of product by using its molar mass:

$0.0145molPbBr_2*\frac{367.01gPbBr_2}{1molPbBr_2} =5.32gPbBr_2$

And the resulting percent yield:

$Y=\frac{4.92g}{5.32g} *100\%\\\\Y=92.5\%$

Regards!

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2 years ago

5. for the following measurements is expressed to three significant figures? a) 0.007 m b) 7077 mg c) 7.30 x 10^-7 km d) 0.070

Maksim231197 [3]

The answer is c
a) 1 sf
b) 4 sf
d) 2 sf

6 0

2 years ago