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Verizon [17]
3 years ago
5

13. Which are the simplest pure substances that cannot be broken down into any other substances?​

Chemistry
2 answers:
Dima020 [189]3 years ago
4 0

Answer:

Elements

Explanation:

Each kind of atom is an element. Elements are pure substances that cannot be broken down into simpler substances by ordinary chemical means.

Sophie [7]3 years ago
4 0

Answer:

Elements

Explanation:

Elements such as those on the periodic table are unable to be broken down into simpler forms.

Mixtures (both homogenous and heterogenous) are made of multiple elements making it able to be physically broken down back to its original elements.

Compounds are also made up of multiple elements, however it must go through a chemical separation process in order for it to be broken down into its original elements.

Matter is a broad term of any substance. So it could both be a combination or a single element making it incorrect for this question.

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How do trends in the periodic table help predict the properties of an element
irina1246 [14]
As you move around there is a change in: electronegativies, ionisation energies, atomic radius etc. different amounts of these properties are going to effect how the element acts
8 0
2 years ago
7.) A syringe initially holds a sample of gas with a volume of 285 mL at 355 K and 1.88 atm. To
marysya [2.9K]

Answer:

T₂ = 721 k

Explanation:

Given data:

Initial volume = 285 mL

Initial pressure = 1.88 atm

Initial temperature = 355 K

Final temperature = ?

Final volume = 435 mL

Final pressure = 2.50 atm

Formula:  

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

Solution:

P₁V₁/T₁ = P₂V₂/T₂  

T₂  =  P₂V₂ T₁  / P₁V₁

T₂ = 2.50 atm × 435 mL × 355 K / 1.88 atm × 285 mL  

T₂ = 386062.5 atm. mL. K /535.8 atm. mL

T₂ = 721 k

5 0
3 years ago
Given the equation C3H8(g) + O2(g) = CO2(g) + H2O(g) and that the enthalpies of formation for H2O(g) = -241.8 kJ/mol, CO2(g) = -
kari74 [83]

Answer: 72.4 kJ/mol

Explanation:

The balanced chemical reaction is,

C_3H_8(g)+5O_2(g)\rightarrow 3CO_2(g)+4H_2O(l)  \Delta H=-2220.1kJ/mol

The expression for enthalpy change is,

\Delta H=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]

\Delta H=[(n_{CO_2}\times \Delta H_{CO_2})+(n_{H_2O}\times \Delta H_{H_2O})]-[(n_{O_2}\times \Delta H_{O_2})+(n_{C_3H_8}\times \Delta H_{C_3H_8})]

where,

n = number of moles

\Delta H_{O_2}=0 (as heat of formation of substances in their standard state is zero

Now put all the given values in this expression, we get

-2220.1=[(3\times -393.5)+(4\times -241.8)]-[(5\times 0)+(1\times \Delta H_{C_3H_8})]

\Delta H_{C_3H_8}=72.4kJ/mol

Therefore, the heat of formation of propane is 72.4 kJ/mol

7 0
3 years ago
Number of Electrons = Number of Protons = Atomic __________________
Stella [2.4K]
Number

The atomic number is the number of protons in one atom of an element.

Hope this helps!
3 0
3 years ago
Read 2 more answers
VOCABULARY<br> 1. What is an ideal gas?
noname [10]

Answer:

a hypothetical gas whose molecules occupy negligible space and have no interactions, and which consequently obeys the gas laws exactly.

Explanation:

7 0
3 years ago
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