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yuradex [85]
3 years ago
8

Which actions represent endothermic reactions? Check all that apply. an instant ice pack becoming cold, splitting a gas molecule

, baking bread, TNT exploding, wood burning in a fire
Chemistry
2 answers:
DerKrebs [107]3 years ago
6 0
Answer is: an instant ice pack becoming cold, splitting a gas molecule and baking bread.

<span>Endothermic reaction is chemical reaction that absorbs more energy than it releases.
</span>In ice pack, <span>reaction absorbs heat from the surroundings (endothermic reaction), lowering the surrounding temperature.
For splitting molecule and baking bread we must add energy to break bonds between atoms.</span>
lys-0071 [83]3 years ago
4 0

Answer:

A,B,C

Explanation:

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Calculate the ratio of the velocity of helium atoms to the velocity of neon atoms at the same temperature.
o-na [289]

Answer:

vHe / vNe = 2.24

Explanation:

To obtain the velocity of an ideal gas you must use the formula:

v = √3RT / √M

Where R is gas constant (8.314 kgm²/s²molK); T is temperature and M is molar mass of the gas (4x10⁻³kg/mol for helium and 20,18x10⁻³ kg/mol for neon). Thus:

vHe = √3×8.314 kgm²/s²molK×T / √4x10⁻³kg/mol

vNe = √3×8.314 kgm²/s²molK×T / √20.18x10⁻³kg/mol

The ratio is:

vHe / vNe = √3×8.314 kgm²/s²molK×T / √4x10⁻³kg/mol / √3×8.314 kgm²/s²molK×T / √20.18x10⁻³kg/mol

vHe / vNe = √20.18x10⁻³kg/mol / √4x10⁻³kg/mol

<em>vHe / vNe = 2.24</em>

<em />

I hope it helps!

8 0
3 years ago
Drag each positive ion to bond it with a negative ion to form the neutral ionic compound indicated.
weeeeeb [17]

Answer:

1. NaCl

2. NH4F

3. MgO

4.LiCl

5. KI

6. CaO

Explanation:

In that order

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2 years ago
How many half-lives are required for three-fourths of the nuclei of an isotope in a sample to decay?
prisoha [69]
2 half lives are required.
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Scientists made the following two observations about emission spectra: each element has a unique emission spectrum. atoms emit e
kondaur [170]
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3 0
3 years ago
Read 2 more answers
Determine whether the given compound name or formula contains a polyatomic ion. N H 4 C l Choose... Magnesium sulfate Choose...
Morgarella [4.7K]

Answer:

NH₄Cl, Magnesium sulfate, KCN

Explanation:

Determine whether the given compound name or formula contains a polyatomic ion.

  • NH₄Cl. YES. It contains the polyatomic ion ammonium NH₄⁺.
  • Magnesium sulfate. YES.  It contains the polyatomic ion sulfate SO₄²⁻.
  • Sodium phosphide Na₃P. NO.
  • SO₃. NO.
  • Calcium hydroxide Ca(OH)₂. NO.
  • KCN. YES. It contains the polyatomic ion cyanide CN⁻.
4 0
3 years ago
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