The third one down: "When barium hydroxide is mixed with ammonium chloride, ice crystals form on the outside of the container."
This is because an endothermic reaction [process] takes in more energy than it releases. Therefore because a decrease in energy leads to a decrease in temperature, the ice crystals forming show that it must be a endothermic reaction [process].
Hope this helps! :)
AJ
The heat required to raise the temperature of a certain mass of sample to a specific temperature change, we use the formula mCpΔT where m is mass, Cp is the specific heat of the substance and ΔT is the temperature change. In this case, we substitute and form 1.25 g x 0.057 cal/g C *20 C equal to 1.425 calories.
The number of C atoms in 0.524 moles of C is 3.15 atoms.
The number of 
molecules in 9.87 moles is 59.43 molecules.
The moles of Fe in 1.40 x 
atoms of Fe is 0.23 x 
The moles of 
in 2.30x
molecules of is 3.81.
<h3>What are moles?</h3>
A mole is defined as 6.02214076 × 
of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
A. The number of C atoms in 0.524 mole of C:
6.02214076 × x 0.524 mole
3.155601758 atoms =3.155 atoms
B. The number of molecules in 9.87 moles of :
6.02214076 × x 9.87
59.4385293 molecules= 59.43 molecules
C. The moles of Fe in 1.40 x atoms of Fe:
1.40 x ÷ 6.02214076 ×
0.2324754694 x moles.
0.23 x moles.
D. The moles of in 2.30x molecules of :
2.30x ÷ 6.02214076 ×
3.819239854 moles=3.81 moles
Learn more about moles here:
brainly.com/question/8455949
#SPJ1
Compounds are elements and its a pure substance with a gised composition.
Mixtures two or more subtances mixed to together.There are 2 type of mixtures.
Homegenous Mixtures (Solutions)-Two or more substances mixed but is uniform, you cant see the different mixtures.
Ex:Sugar mixed with water.The sugar dissolves and becomes one with the water.
Heterogeneous Mixtures-Two or more substances mixed but is not uniformed.You can see all the substances put into the mixture.
Ex:A salad, you can see whats all mixed in the sald and can pick it apart.
In a neutral atom they are both equal, and their even quantities makes the atom neutral...
