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.”
Answer:
Elaina's scientific investigation is missing controlled variables.
Explanation:
A good scientific investigation should vary only the factor that is studied (the speed of the music. All other factors should be kept constant.
She hasn’t controlled for <em>volume</em>. The volume of the music may affect the rate at which the listener’s heart rate will increase. She should have measured each person’s pulse after the same period of listening.
She hasn’t controlled for <em>age</em>. A grandmother may respond to loud music differently from a teenager. All her subjects should be about the same age.
She hasn’t controlled for <em>wakefulness</em>. A person may respond to music differently when awake than when asleep.
Answer:
0.74 grams of methane
Explanation:
The balanced equation of the combustion reaction of methane with oxygen is:
it is clear that 1 mol of CH₄ reacts with 2 mol of O₂.
firstly, we need to calculate the number of moles of both
for CH₄:
number of moles = mass / molar mass = (3.00 g) / (16.00 g/mol) = 0.1875 mol.
for O₂:
number of moles = mass / molar mass = (9.00 g) / (32.00 g/mol) = 0.2812 mol.
- it is clear that O₂ is the limiting reactant and methane will leftover.
using cross multiplication
1 mol of CH₄ needs → 2 mol of O₂
??? mol of CH₄ needs → 0.2812 mol of O₂
∴ the number of mol of CH₄ needed = (0.2812 * 1) / 2 = 0.1406 mol
so 0.14 mol will react and the remaining CH₄
mol of CH₄ left over = 0.1875 -0.1406 = 0.0469 mol
now we convert moles into grams
mass of CH₄ left over = no. of mol of CH₄ left over * molar mass
= 0.0469 mol * 16 g/mol = 0.7504 g
So, the right choice is 0.74 grams of methane
Speed of the car = 
Given time = 37.0 s
Converting time from seconds to hours:
1 hr= 60 min; 1 min = 60 s
Calculating distance from speed and time:
Converting distance from km to m:
So the distance traveled by the car in 37.0 s is 894 m.
Each state is allocated a number of electors equal to the number of its U.S. Senators
