Answer: 25,200.
Explanation:
1) Given: 4.659 × 10⁴ - 2.14 × 10⁴
2) You have to deal with significant figures.
Since, the powers are the same (10⁴) you can directly subtract the decimal numbers. But first analyze the significant figures and the number of decimal digits.
3) The number 4.659 × 10⁴ has four significant figures (4, 6, 5, and 9), while the number 2.14 × 10⁴ has three significan figures (2, 1, and 4).
4) When you add or subtract numbers with diferent amount of decimal digits, the result must show the same number of decimal digits as the term with the least number of decimal digits.
5) Before subtracting, you must round all the terms to the least number of decimal digits. So, since 2.14 has two decimal digits and 4.659 has three decimal digits, you shall round 4.659 to 4.66.
6) Now you subtract 4.66 - 2.14 = 2.52
7) Multiply by the power of 10: 2.52 × 10⁴ = 25,200. And that is the answer.
First lets calculate the moles of aluminum (molar mass is 27 gram/mol):
n = m/M = 14.9 / 27 = 0.551 mole of Al
According to the reaction between sulfuric acid and aluminum:
From 2 moles of aluminum ==> we get 3 moles of Hydrogen gas
so, let's do cross multiplication
0.551 ==> 0.551 * 3/2 = 0.83 mole of H2
So, from this reaction we got 0.83 mole of H2 gas
knowing that the molar mass of H2 is 2 gram/mol, the mass of the gas is.
m = n * M = 0.83 * 2 = 1.66 gram of H2
Answer: W
Explanation:
The cell in liquid W will look the smallest out of the four because of Osmosis.
Osmosis is a process by which water molecules move from an area of relatively higher concentration of water to an area with a relatively lower concentration through a selectively permeable membrane(cell membrane).
With W being saltier than the cell, water molecules will move from the cell to liquid W to balance the concentrations inside and outside the cell which will lead to the cell in W being smaller.
B- ammonia. ammonia has a pH level of about 11, and anything higher than 7 is more basic and anything less than 7 is more acidic. 7 is considered neutral.
A charge of -3 means it gained 3 electrons meaning electrons would go from 15 to 18 because protons and electrons are the same and you start with 15.
So your answer is 15 protons, 18 electrons
