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liubo4ka [24]
3 years ago
11

Which of the following describes air pressure?

Chemistry
1 answer:
ira [324]3 years ago
4 0

Answer:

the weight of the atmosphere pressing down on Earth

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Does his model correctly show why the properties of the ending substances are different from the properties of the starting subs
topjm [15]

Answer:

Samira's model is incorrect because not all atoms are accounted for

Explanation:

The image of Samira's model has been attached to this answer to enhance the explanation.

What is depicted in that model is rightly regarded as a chemical change. In a chemical change atoms of substances are rearranged as new substances are formed.

However, all atoms in the products must also be found in at least one of the reactants. In this case we have an atom in one of the products that is not accounted for. Hence the model is incorrect.

6 0
3 years ago
A mineral forms from water at the edge of a lake.
irga5000 [103]

Answer:C

Explanation:The mineral is only formed when hot water cooler

8 0
3 years ago
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7. What must you do before you make a hypothesis?
almond37 [142]

Answer:

Ask a question?

Explanation:

look at the scientific method uwu

6 0
3 years ago
How much energy is required to vaporize 155 g of butane at its boiling point? the heat of vaporization for butane is 23.1 kj/mol
netineya [11]

The energy required to vaporize 155 g of butane at its boiling point: 61,723 kJ

<h3>Further explanation</h3>

Enthalpy is the amount of system heat at constant pressure.

The enthalpy is symbolized by H, while the change in enthalpy is the difference between the final enthalpy and the initial enthalpy symbolized by ΔH.

\large{\boxed{\boxed{\bold{\Delta H=H_{End}-H_{First}}}}

Delta H reaction (ΔH) is the amount of heat change between the system and its environment

(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)

The standard unit is kilojoules (kJ)

The enthalpy change symbol (ΔH) is usually written behind the reaction equation.

Change in Standard Evaporation Enthalpy (ΔH vap) is a change in enthalpy at the evaporation of 1 mol liquid phase to the gas phase at its boiling point and standard pressure.

Examples of water evaporation:

 H₂O (l) ---> H₂O (g); ΔH vap = + 44kJ

The enthalpy of evaporation is positive because its energy is needed to break the attraction between molecules in a liquid

  • 155 g of butane

relative molecular mass of butane (C₄H₁₀) = 4.12 + 10.1 = 58 gram / mol

tex]\large{\boxed{mole\:=\:\frac{grams}{relative\:molecular\:mass}}}[/tex]

\large mole\:=\:\large \frac{155}{58}

mole = 2,672

Since the heat of vaporization for butane is 23.1 kj / mol, the energy needed to evaporate 2,672 moles of butane is:

23.1 kJ / mol x 2,672 mol = 61,723 kJ

<h3>Learn more</h3>

the heat of vaporization

brainly.com/question/11475740

The latent heat of vaporization

brainly.com/question/10555500

brainly.com/question/4176497

Keywords: the heat of vaporization, butane, mole, gram, exothermic, endothermic

4 0
4 years ago
Read 2 more answers
Given a balanced chemical equation below: 3Cu(s) + 2H3PO4 --- &gt; Cu3(PO4)2 + 3H2 How many moles of copper are needed to react
Harman [31]

Answer:

7.5 moles

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

3Cu + 2H3PO4 —> Cu3(PO4)2 + 3H2

From the balanced equation above,

3 moles of Cu reacted with 2 moles of H3PO4.

Therefore, Xmol of Cu will react with 5 moles of H3PO4 i.e

Xmol of Cu = (3 x 5)/2

Xmol of Cu = 7.5 moles

Therefore, 7.5 moles of Cu are needed to react with 5 moles of H3PO4.

4 0
3 years ago
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