Answer:
eight oxygen atoms
Explanation:
This formula shows that in one mole of this compound, there are 3 moles of Ca atoms that combine with 2 moles of the PO4(phosphate) groups, which gives a total of 2 moles of P atoms and 8 moles of 0 atoms.
Explanation:
- Evaporation is defined as a process in which liquid state of water is changing into vapor state.
So, we need to break the bonds of liquid substance in order to convert it into vapor state. And, energy is absorbed for breaking of bonds which means that evaporation is an endothermic process.
Hence, the statement evaporation of water is an exothermic process is false.
- When a hydrocarbon reacts with oxygen and leads to the formation of carbon dioxide and water then this type of reaction is known as combustion reaction.
A combustion reaction will always release heat energy. Hence, combustion reaction is exothermic in nature.
- When energy is transferred as heat from the surroundings to the system then it means energy is being absorbed by the system. And, absorption of heat is an endothermic process for which is positive.
- Whereas when energy is transferred from system to the surrounding then it means energy is released by the system which is an exothermic process.
Hence, for an exothermic process value of is negative.
Thus, we can conclude that statements which are true are as follows.
- A combustion reaction is exothermic.
- When energy is transferred as heat from the system to the surroundings, is negative.
- For an endothermic reaction Deta H is positive.
Answer:
0.1082M of Barium Hydroxide
Explanation:
KHP reacts with Ba(OH)2 as follows:
2KHP + Ba(OH)2 → 2H2O + Ba²⁺ + 2K⁺ + 2P²⁻
<em>Where 2 moles of KHP reacts per mole of barium hydroxide</em>
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To solve this question we must find the moles of KHP in 1.37g. With these moles and the reaction we can find the moles of Ba(OH)2 and its molarity using the volume of the solution (31.0mL = 0.0310L) as follows:
<em>Moles KHP -Molar mass: 204.22g/mol-</em>
1.37g * (1mol / 204.22g) = 0.006708 moles KHP
<em>Moles Ba(OH)2:</em>
0.006708 moles KHP * (1mol Ba(OH)2 / 2mol KHP) =
0.003354 moles Ba(OH)2
<em>Molarity:</em>
0.003354 moles Ba(OH)2 / 0.0310L =
<h3>0.1082M of Barium Hydroxide</h3>
Answer:
J.J. Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup."