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dalvyx [7]
2 years ago
10

Which statements accurately describe elements? Check all that apply.

Chemistry
2 answers:
svet-max [94.6K]2 years ago
7 0

Answer:

  • Elements are made up of only one type of atom.
  • Each element has a unique chemical symbol.
  • Elements can be identified by their atomic number.

Explanation:

alex41 [277]2 years ago
4 0

Answer:

2,3,4

Explanation:

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Very important !!!!!!!!!!!!
Mademuasel [1]
They speed up reactions by lowering activation energy. Many enzymes change shape when substrates bind.
8 0
3 years ago
A sample of pure NO2 is heated to 335 ∘C at which temperature it partially dissociates according to the equation 2NO2(g)⇌2NO(g)+
vodka [1.7K]

The equilibrium constant for the reaction is 0.00662

Explanation:

The balanced chemical equation is :

2NO2(g)⇌2NO(g)+O2(g

At t=t  1-2x ⇔ 2x + x moles

The ideal gas law equation will be used here

PV=nRT

here n= \frac{w}{W} = \frac{w}{V}= density

P = \frac{density RT}{M}       density is 0.525g/L, temperature= 608.15 K, P = 0.750 atm

putting the values in reaction

0.75 = \frac{0.525 x 0.0821 x 608.15 }{M}

  M    = 34.61

         

to calculate the Kc

Kc=\frac{ [NO] [O2]}{NO2}

  \frac{1-2x}{1+x} x M NO2 + \frac{2x}{1+x} M NO+ \frac{x}{1+x} M O2

Putting the values as molecular weight of NO2, NO,O2

\frac{46(1-2x) +30(2x)+32x}{1+x}

34.61= \frac{46}{1+x}

x= 0.33

Kc= \frac{4x^2)x}{1-2x^2}

    putting the values in the above equation

Kc = 0.00662

     

5 0
2 years ago
3. What is the easiest way to create electron configurations?
jarptica [38.1K]

Answer:

To calculate an electron configuration, divide the periodic table into sections to represent the atomic orbitals, the regions where electrons are contained. Groups one and two are the s-block, three through 12 represent the d-block, 13 to 18 are the p-block and the two rows at the bottom are the f-block.Explanation:

6 0
3 years ago
Which description is true of 0.02 M Ca(OH)2 if Ca(OH)2 completely dissociates in water? A. It’s a dilute strong acid. B. It’s a
Sphinxa [80]

Answer: B. It’s a dilute strong base.


Explanation:


1) Definition of acids and bases: as per Bronsted-Lowry model, an acid is a substance that donates hydrogen ions and a base is a substance that accepts hydrogen ions.

Ca(OH)₂ does not have hydrogen ions to donate, but it can accept hydrogen ions to form H₂O according to this equation: H⁺ + OH⁻ → H₂O.

Hence,  Ca(OH)₂ is a base.


2) Definition of strong base: a strong base is a base that dissociates completely into metallic and hydroxide ions in aqueous solutions, while a weak base dissociates partially.


Hence, Ca(OH)₂ is a strong base.


3) Definition of dilute: it refers to a solution meaning that the substance is not pure and the concentration is low. Since, the solution the Ca(OH)₂ is 0.02 M means that it is dilute.


Therefore, we have found that the description of 0.02 M Ca(OH)₂ is that is is a dilute strong base (option B).


5 0
3 years ago
Write two advantages and two disadvantage of hydrogen<br>​
kykrilka [37]
1.it is readily available since hydrogen is a basic earth element and it's very abundant.
2. It doesn't produce harmful emissions.
Disadvantages
1.it is expensive. It is expensive because it takes a lot of time to separate the element from others.
2.it is difficult to store. Even moving a tiny bit of hydrogen would be very expensive.
3. It is highly flammable. Since it is a very powerful source of fuel, hydrogen can be very flammable.
8 0
3 years ago
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