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3 years ago

Why does dry ice scream when pushed onto metal?

Chemistry

2 answers:

alisha [4.7K]3 years ago

7 0

Answer:

i thought you said dry ice cream

Shtirlitz [24]3 years ago

5 0

Because metals are good conductors they can transfer ambient heat to the surface of the dry ice.

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A civil engineering student is considering buying an electric car. However, the conscious student wants to make sure her carbon

svetlana [45]

Answer:

$\text{An gasoline-powered vehicle has }\\\boxed{\text{five times the carbon footprint}}\text{ of an electric vehicle.}$

Explanation:

1. Miles travelled in an average month

$\text{Miles} = \text{1 mo} \times \dfrac{\text{52 wk}}{\text{12 mo}} \times \dfrac{\text{5 da}}{\text{1 wk}} \times \dfrac{\text{16 mi}}{\text{1 da}} = \text{347 mi}$

2. Using a gasoline powered vehicle

(a) Moles of heptane used

$n = \text{347 mi} \times \dfrac{\text{1 gal}}{\text{36.5 mi}}\times \dfrac{\text{3.785 L}}{\text{1 gal}} \times \dfrac{\text{679.5 g}}{\text{1L}} \times \dfrac{ \text{1 mol}}{\text{100.20 g}}= \text{244 mol}$

(b) Equation for combustion

C₇H₁₆ + O₂ ⟶ 7CO₂ + 8H₂O

(c) Moles of CO₂ formed

$n = \text{244 mol heptane} \times \dfrac{\text{7 mol CO$_{2}$}}{\text{1 mol heptane}} = \text{1710 mol CO$_{2}$}$

(d) Volume of CO₂ formed

At 20 °C and 1 atm, the molar volume of a gas is 24.0 L.

$V = \text{1710 mol } \times \dfrac{\text{24.0 L}}{\text{1 mol}} \times \dfrac{\text{1 gal}}{\text{3.785 L}} = \textbf{10 800 gal}$

3. Using an electric vehicle

(a) Theoretical energy used

$\text{Theor. Energy} = \text{347 mi} \times \dfrac{\text{1 kWh}}{\text{5.2 mi}} = \text{66.7 kWh theor.}$

(b) Actual energy used

The power station is only 85 % efficient.

$\text{Actual energy used} = \text{66.7 kWh theor.} \times \dfrac{\text{100 kWh actual}}{\text{ 85 kWh theor.}}\times \dfrac{\text{3600 kJ}}{\text{1 kWh}}\\\\ = 2.82\times 10^{5} \text{ kJ}\$

(c) Combustion of CH₄

CH₄ + 2O₂ ⟶ CO₂ +2 H₂O

(d) Equivalent volume of CO₂

The heat of combustion of methane is -802.3 kJ·mol⁻¹

$V= 2.82\times 10^{5}\text{ kJ} \times \dfrac{\text{1 mol methane}}{\text{802.3 kJ}} \times \dfrac{\text{1 mol CO$_{2}$} }{\text{1 mol methane}} \times \dfrac{ \text{24.0 L}}{ \text{1 mol CO$_{2}$}}\\\\ \times \dfrac{\text{1 gal}}{\text{3.875 L}} = \textbf{2180 gal}$

4. Comparison

$\dfrac{V_{\text{gasoline}}}{V_{\text{electric}}} = \dfrac{10800}{2180} = 5.0\\\\ \text{An gasoline-powered vehicle has }\\ \boxed{\textbf{ five times the carbon footprint}}\text{ of an electric vehicle.}$

6 0

3 years ago

Solar radiation provides more heat and cleaner than near the pools on Earth the greatest amount of heat is moved away from the e

Rashid [163]

Answer:

Ocean Currents

Explanation:

The correct answer is Ocean currents.

When the earth receives solar radiation, a large fraction of this incident radiation is usually absorbed by the oceans and the seas, which become warm. Usually, equitorial regions are the ones that have this phenomenon. Now, when ocean currents are flowing from the equator, they usually carry this warm water with them thereby moving the greatest amount of heat from the equator on its way out.

For example, In the Pacific Ocean, there is a current known as Alaska Current that carries warm water in the northward direction thereby making Anchorage which is Alaska's largest city to have a much mild weather than the inland areas with the same latitude.

4 0

2 years ago

If I contain 3 moles of gas in a container with a volume of 60 liters and at a

viktelen [127]

Answer: n = 3.0 moles

V = 60.0 L

T = 400 K

From PV = nRT, you can find P

P = nRT/V = (3.0 mol)(0.0821 L-atm/K-mol)(400 K)/60.0L

P = 1.642 atm = 1.6 atm (to 2 significant figures)

4 0

3 years ago

Read 2 more answers

As ________________ increases, air pressure decreases. A) pollution B) water vapor C) radiation D) altitude

lara [203]

Answer:

d or b

Explanation:

8 0

3 years ago

Which information is represented by a line on this map?

Ivanshal [37]

The correct answer is: [A]: "<span>points with the same elevation" .
________________________________________________________</span>

4 0

3 years ago