Answer:
a) 12/323
b) 8/233
Explanation:
a) The probability of a red ball being drawn is 12/38, or in a simplified fraction, 6/19. To find the probability that 3 are red you would multiply the probability of the fraction for each, except subtracting one from the total each time as the drawn is done without replacement. This is done as follows: 6/19 × 6/18 × 6/17= 12/323
b) The probability of drawing a blue ball is 8/38, or 4/19. To find that the first one is blue and the rest are red, the equation is done as follows: 4/19 × 6/18 × 6/17 = 8/233
(hopefully I did this right)
Answer: Thomson's showed that atoms contain smaller particles, so it was important to change the theory of daltons. Rutherford found that most of of an atom is hollow and in the middle of an atom is concentrated energy. This contributed to the revision of the plum pudding model.
Answer:
747mL of the 0.157mL are needed
Explanation:
To find the grams of salt we need to convert these grams to moles using molar mass of magnesium nitrate (148.3g/mol). Then, with the molar concentration we can convert the moles to liters and, as last, to milliliters, as follows:
<em>Moles Mg(NO₃)₂:</em>
17.4g * (1mol / 148.3g) = 0.117 moles of magnesium nitrate
<em>Volume:</em>
0.117 moles * (1L / 0.157moles) = 0.747L
= 747mL of the 0.157mL are needed
<em>In a 0.157M solution there are 0.157 moles per liter of solution</em>
During the experiment, scientists noted that several of the reaction beakers became hot to the touch. All of the following reactions could cause this result except endothermic and positive ∆H experiments.
<u>Explanation:</u>
If the beakers are becoming hot during experimentation, then that means the energy is being released from the reactants during this experiment. As the energy is being released that enthalpy change will also be negative as the enthalpy change is calculated as the difference of enthalpy of reactants from products.
So in these cases, heat is released making the beakers hot. So for the exceptional case, the experiment should be endothermic in nature and positive enthalpy change should be there in the experiment. Such that the heat will not be released leading to no heating of beakers.
<span>When there is still solvent with the product because it was not dried properly during the experiment,so,this </span><span>might cause the percent yield of sodium chloride to be less than 100%.</span>
