If the uncertainty of a certain measurement instrument is not given, then it is assumed to be equal to half of the least count of that instrument. In this case, the least count is 10 ml, so half of this is 5 ml. Therefore, the graduated cylinder has an uncertainty of +/- 5 ml
Answer:
a solution color becoming less intense due to dilution- is not an evidence of a chemical reaction
bubbles (gas formation) - evidence of a chemical reaction
explosion or fire - evidence of a chemical reaction
changes in color- evidence of a chemical reaction
precipitation- evidence of a chemical reaction
changes in temperature - evidence of a chemical reaction
a solid liquifying - is not an evidence of a chemical reaction
solution colors mixing - is not an evidence of a chemical reaction
Explanation:
A chemical change is not easily reversible and yields new substances. It is often accompanied by a loss or gain of heat.
In the answer section, i have shown some evidences that lead us to conclude that a chemical reaction has taken place. The occurrence of a chemical change often goes with the formation of new substances as earlier stated and any of these signs may accompany the process.
For instance, when a metal is dropped in dilute acid solution, bubble of hydrogen gas indicates that a chemical reaction has taken place.
<span>To answer this question, you need to change the sodium phosphate unit into mol and doing the reaction. Sodium phosphate or Na3PO4 molecular weight is 163.94 or 164 rounded up. Then the amount should be: 492g/ (164g/mol)= 3 mol
For every 1 mol of </span>Na3PO4 there are 4 mol of oxygen element. To made 1 mol of O2 molecule, you will need 2 mol oxygen element. Then the amount of oxygen should be: 4/2 * 3 mol= 6 mol * 6.02 * 10^23= 36.12 * 10*23= 3.61 * 10^24
Answer:
t=(70)ln(19.9/20)/-ln2
70 is the years. 19.9 kg is what is left after 0.1kg decay. 20kg is your initial amount.
t=0.506 years with a decay constant of 0.0099021/year
Explanation:
Indefinite shape and definite volume I’m pretty sure I could be wrong tho