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3 years ago

Helpp me pls 50 points

Chemistry

2 answers:

Alecsey [184]3 years ago

7 0

4th pic is solid, gas

and the other one is further apart; increase

5th pic for second question is D

and the first question is kinetic energy

yw bakugo

Irina-Kira [14]3 years ago

6 0

Use socratic it is very helpful it uses everything on the internet to search for answers bc it is a search engine

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Sand dunes protect beaches against erosion and flooding due to storms.

kogti [31]

Answer:

B. Building houses near the beach

Explanation:

it was right on edge

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4 years ago

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Give the percent yield when 28.16 g of CO2 are formed from the reaction of 4.000 moles of C8H18 with 4.000 moles of O2.

ludmilkaskok [199]

Answer:

Percentage yield = 25%

Explanation:

Given data:

Moles of C₈H₁₈ = 4 mol

Moles of O₂ = 4 mol

Actual yield of CO₂ = 28.16 g

Percentage yield = ?

Solution:

Chemical equation:

2C₈H₁₈ + 25 O₂ → 16CO₂ + 18H₂O

Now we will compare the moles of CO₂ with O₂ and C₈H₁₈.

C₈H₁₈ : CO₂

2 : 16

4 : 16/2×4=32 mol

O₂ : CO₂

25 : 16

4 : 16/25×4=2.56 mol

Mass of CO₂:

Mass = number of moles× molar mass

Mass = 2.56 mol ×44 g/mol

Mass = 112.64 g

Percentage yield:

Percentage yield = Actual yield /theoretical yield × 100

Percentage yield = 28.16 g / 112.64 g× 100

Percentage yield = 0.25× 100

Percentage yield = 25%

5 0

3 years ago

What best defines concentration

zmey [24]

When you focus on something

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3 years ago

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the combustion of 0.1240 kg of propane in the presence of excess oxygen produces 0.3110kg of carbon dioxide what is the limittin

mote1985 [20]

Answer:

Propane

Explanation:

From the question given, we were told that 0.1240 kg of propane reacted with excess oxygen to produce 0.3110kg of carbon dioxide.

Since the reaction took place in the presence of excess oxygen, therefore, propane is the limiting reactant as all of it is used up in the presence of excess oxygen.

4 0

3 years ago

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Perform the calculation and record the answer with the correct number of significant figures.

kotykmax [81]

The question is incomplete, here is the complete question:

A. (6.5-6.10)/3.19

B. (34.123 + 9.60) / (98.7654 - 9.249)

Answer:

For A: The answer becomes 0.1

For B: The answer becomes 0.4884

Explanation:

Significant figures are defined as the figures present in a number that expresses the magnitude of a quantity to a specific degree of accuracy.

Rules for the identification of significant figures:

Digits from 1 to 9 are always significant and have infinite number of significant figures.
All non-zero numbers are always significant. For example: 664, 6.64 and 66.4 all have three significant figures.
All zeros between the integers are always significant. For example: 5018, 5.018 and 50.18 all have four significant figures.
All zeros preceding the first integers are never significant. For example: 0.00058 has two significant figures.
All zeros after the decimal point are always significant. For example: 2.500, 25.00 and 250.0 all have four significant figures.
All zeroes used solely for spacing the decimal point are not significant. For example: 10000 has one significant figure.

Rule applied for addition and subtraction:

The least precise number present after the decimal point determines the number of significant figures in the answer.

Rule applied for multiplication and division:

In case of multiplication and division, the number of significant digits is taken from the value which has least precise significant digits

For A: (6.5-6.10)/3.19

This a a problem of subtraction and division.

First, the subtraction is carried out.

$\Rightarow \frac{6.5-6.10}{3.19}=\frac{0.4}{3.19}$

Here, the least precise number after decimal was 1.

$\Rightarrow \frac{0.4}{3.19}=0.125$

Here, the least precise number of significant digit is 1. So, the answer becomes 0.1

For B: (34.123 + 9.60) / (98.7654 - 9.249)

This a a problem of subtraction, addition and division.

First, the subtraction and addition is carried out.

$\Rightarow \frac{34.123+9.60}{98.7654-9.249}=\frac{43.723}{89.5164}=\frac{43.72}{89.516}$

Here, the least precise number after decimal in addition are 2 and in subtraction are 3

$\Rightarrow \frac{43.72}{89.516}=0.48840$

Here, the least precise number of significant digit are 4. So, the answer becomes 0.4884

6 0

3 years ago