Answer:
Exothermic reaction for the HCl, endothermic reaction for the water

Explanation:
Heat was lost by HCl as its temperature lowered, so it was an exothermic reaction for the HCL.
Heat was gained by water as its temperature increased, so it was an endothermic reaction for the water.
m = Mass of water = 100 g
c = Specific heat of water = 
= Change in temperature of water = 
Heat is given by

Heat gained by water is
.
Pole
Explanation:
A magnetic pole is the point on a magnet where a magnet effect is strongest. Around a magnet, there are magnetic fields.
- The magnetic fields are force fields that leaves the north poles and enters through the south.
- The pole is where magnetic effects are the strongest.
- It is around the pole that the strongest magnetic effect on a magnet or magnetic material is felt.
- The strength of magnetic fields are strongest at the poles.
learn more:
electromagnet brainly.com/question/2191993
#learnwithBrainly
<h2>~<u>Solution</u> :-</h2>
- Here, to find the atomic mass of element, we must;
We know that,
- 4.6 x $ \sf{10^{22}}$ atoms of an element weigh 13.8g.
Thus,
The atoms of $ \sf{ 6.02 \times 10^{13}}$ will weigh;


- Hence, the molar mass (atomic mass) will be <u>180.6 g.</u>
Answer:
26.3 moles of O₂ are needed to react completely with 35.0 mol of FeCl₃
Explanation:
To determine the number of moles of O₂ that are needed to react completely with 35.0 mol of FeCl₃, it is possible to use the reaction stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), and rule of three as follows: if 4 moles of FeCl₃ react with 3 moles of O₂, 35 moles of FeCl₃ with how many moles of O₂ will it react?

moles of O₂= 26.25 ≅ 26.3
<u><em>26.3 moles of O₂ are needed to react completely with 35.0 mol of FeCl₃</em></u>
Answer:
The expression to calculate the mass of the reactant is 
Explanation:
<em>The amount of heat released is equal to the amount of heat released per gram of reactant times the mass of the reactant.</em> To keep to coherence between units we need to transform 1,080 J to kJ. We do so with proportions:

Then,
