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2 years ago

PPPPPPPPLLLLLLLLLLLLLLZZZZZZZZZZ HELP ME ITS ALREDY OVER DUE PLZ HELP ME PPPLLLZZZ I NEED IT IM DESPRET

Chemistry

2 answers:

eimsori [14]2 years ago

4 0

Answer:

1) Big Bang Theory

2) we are in the "expanding phase" of the big bang theory

Explanation:

nikitadnepr [17]2 years ago

3 0

Answer:

1) Big Bang Theory

2) we are in a phase of the big bang theory

Explanation:

So for number 1 the answer is the -big bang theory- and number 2 there is a theory that pretty much says that were in a constant cycle. what I mean is theoretically in a couple million years the entire universe will form together again into another dense ball and repeat the process. So basically the universe is still in the "expanding phase" and that's what backs up the theory of the big bang (the fact that were in one of the big bang theory's "phases")

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Use the periodic table to write the electron configuration of selenium (Se). s s p d 1 2 3 4 6 10

maw [93]

Answer: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^4

Explanation:

I suggest looking at the electron configuration chart, it has really helped me a lot :)

4 0

3 years ago

Read 2 more answers

C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l), ΔH = –1.37 × 103 kJ For the combustion of ethyl alcohol as described in the above equati

babymother [125]

Answer:

The true statements are: I. The reaction is exothermic.

II. The enthalpy change would be different if gaseous water was produced.

Explanation:

The given chemical reaction: C₂H₅OH(l) + 3O₂(g) → 2CO₂(g) + 3H₂O(l), ΔH= -1.37×10³kJ

1. In an exothermic reaction, heat or energy is released from the system to the surrounding. Thus for an exothermic process the change in enthalpy is less than 0 or negative (ΔH < 0) .

Since the enthalpy change for a combustion reaction is negative. <u>Therefore, the given reaction is exothermic.</u>

2. The change in enthalpy (ΔH) of a reaction is equal to difference of the sum of standard enthalpy of formation (ΔHf°) of the products and the reactants.

ΔHr° = ∑ n.ΔHf°(products) − ∑ n.ΔHf°(reactants)

As the value of ΔHf° of water in gaseous state and liquid state is not the same.

<u>Therefore, the enthalpy change of the reaction will be different, if gaseous water was present instead of liquid water.</u>

3. An oxidation-reduction reaction or a redox reaction involves simultaneous reduction and oxidation processes.

The given chemical reaction, represents the combustion reaction of ethanol.

Since combustion reactions are redox reactions. <u>Therefore, the given combustion reaction is an oxidation-reduction reaction.</u>

4. According to the ideal gas equation: P.V =n.R.T

Volume (V) ∝ n (number of moles of gas)

Since the number of moles (n) of gaseous reactants is 3 and number of moles of gaseous (n) products is 2.

<u>Therefore, the volume occupied by 3 moles of the reactant gaseous molecules will be more than 2 moles product gaseous molecules.</u>

3 0

3 years ago

The Element rhenium has two naturally occurring isotopes, 185 Re and 187 Re, with an average atomic mass of 186.207 amu. Rhenium

BigorU [14]

To calculate the average mass of the element, we take the summation of the product of the isotope and the percent abundance. In this case, the equation becomes 186.207=187*0.626+185*x where x is the percent abundance of 185. The answer is 0.374 or 37.4%. This can also be obtained by 100%-62.6%= 37.4%.

8 0

3 years ago

7. Complete the concept map below.

Ilya [14]

Drainage that is not handled properly can cause an increase in erosion, changes in stormwater runoff, flooding, and damage to water quality.

<h3>Natural Disaster?</h3>

Large-scale geological or meteorological phenomena that have the potential to cause loss of life or property are considered natural disasters.
Tornadoes and severe storms are examples of these catastrophes. Tropical Storms and Hurricanes. Floods.
They release significant amounts of gas and dust into the atmosphere, particularly the upper atmosphere, which temporarily alters the climate on Earth.
Large volcanic eruptions should be followed by a drop in the average surface temperature, which is actually seen and lasts for typically 1 to 3 years.
Deforestation and the combustion of fossil fuels have detrimental environmental effects that directly affect the biosphere. Pollutant emissions and carbon dioxide have a negative impact on all types of life.

To learn more about Natural Disaster refer to:

brainly.com/question/13800641

#SPJ13

4 0

1 year ago

For the reaction so3 + h2o h2so4, calculate the percent yield if 500. g of sulfur trioxide react with excess water to produce 57

Lelu [443]

The % yield if 500 g of sulfur trioxide reacted with excess water to produce 575 g of sulfuric acid is calculated using the below formula

% yield = actual yield/ theoretical yield x100

actual yield =575 grams
to calculate theoretical yield
find the moles of SO3 used =mass/molar mass
= 500g/ 80 g/mol =6.25 moles

SO3+H2O=H2SO4
by use of mole ratio of SO3 : H2SO4 which is 1:1 the moles of H2SO4 is also= 6.25 moles

the theoretical yield of H2SO4 is therefore = moles /molar mass
= 6.25 x98= 612.5 grams

%yield is therefore= 575 g/612 g x100= 93.9 %

5 0

3 years ago