If you do not wait until the crucible is at room temperature, its density will vary constantly until it reaches this temperature, since density is a property that varies with temperature. For the above reason, weighing a hot crucible will not allow the measurement of a constant weight on the balance, since <u>the weight of the object will be constantly changing, which will not allow a constant reading.</u>
Answer:
laws
Explanation:
in some areas and countries there is a limit on how many children someone can have, this would clearly regulate population growth.
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Answer:
0.075
Explanation:
First obtain the mean of the measurement;
Mean = 10.15 + 9.95 + 9.99 + 10.02/4 = 10.03
Then obtain d^2= (mean-score)^2 for each score;
(10.15-10.03)^2 = 0.0144
(9.95-10.03)^2 = 0.0064
(9.99-10.03)^2 = 0.0016
(10.02-10.03)^2= 0.0001
∑d^2= 0.0144 + 0.0064 + 0.0016 + 0.0001
∑d^2= 0.0225
Variance = ∑d^2/N = 0.0225/4 = 0.005625
Standard deviation= √0.005625
Standard deviation= 0.075
Taking into account the reaction stoichiometry, you can observe that:
- one mole of Ca₃P₂ produces 2 mol of PH₃.
- the mole ratio between phosphine and calcium phosphide is 2 mol PH₃ over 1 mol Ca₃P₂.
<h3>Reaction stoichiometry</h3>
In first place, the balanced reaction is:
Ca₃P₂ + 6 H₂O → 3 Ca(OH)₂ + 2 PH₃
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
- Ca₃P₂:1 mole
- H₂O: 6 moles
- Ca(OH)₂: 3 moles
- PH₃: 2 moles
The molar mass of the compounds is:
- Ca₃P₂: 182 g/mole
- H₂O: 18 g/mole
- Ca(OH)₂: 74 g/mole
- PH₃: 34 g/mole
Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:
- Ca₃P₂: 1 mole ×182 g/mole= 182 grams
- H₂O: 6 moles× 18 g/mole= 108 grams
- Ca(OH)₂: 3 moles ×74 g/mole= 222 grams
- PH₃: 2 moles ×34 g/mole= 68 grams
<h3>Correct statements</h3>
Then, by reaction stoichiometry, you can observe that:
- one mole of Ca₃P₂ produces 2 mol of PH₃.
- the mole ratio between phosphine and calcium phosphide is 2 mol PH₃ over 1 mol Ca₃P₂.
Learn more about the reaction stoichiometry:
<u>brainly.com/question/24741074</u>
<u>brainly.com/question/24653699</u>
