Answer:
One of the errors for low percentage of magnesium could be because not all the magnesium may have reacted.
Explanation:
During the heating process, if the magnesium have not reacted completely, it can lead to low percentage of magnesium in the oxide formed. The product may still look a bit greyish rather than whitish after the heating process.
Answer:
Alpha particle
Explanation:
The helium symbol is also used to represent he alpha particles.
For example:
The americium with atomic wight 224 undergo alpha decay and produce
₉₃Np²³⁷ . The alpha particle emitted is also called helium nuclei. During this decay some gamma radiations also produce as a byproduct.
₉₅Am²²⁴ → ₉₃Np²³⁷ + ₂He⁴
Properties of alpha radiation:
Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number 4 less than and atomic number 2 less than the starting atom.
Alpha radiations can travel in a short distance.
These radiations can not penetrate into the skin or clothes.
These radiations can be harmful for the human if these are inhaled.
These radiations can be stopped by a piece of paper.
Explanation:
pH indicators are weak acids that exist as natural dyes and indicate the concentration of H+ (H3O+) ions in a solution via color change. A pH value is determined from the negative logarithm of this concentration and is used to indicate the acidic, basic, or neutral character of the substance you are testing.
Answer:
27.98g/mol
Explanation:
Using ideal gas law equation;
PV = nRT
Where;
P = pressure (atm)
V = volume (L)
T = temperature (K)
n = number of moles (mol)
R = gas law constant (0.0821 Latm/molK)
According to the information given:
V = 2.5L
P = 1.4 atm
T = 282K
n = ?
Using PV = nRT
n = PV/RT
n = 1.4 × 2.5/0.0821 × 282
n = 3.5/23.1522
n = 0.151mol
Using the formula to calculate molar mass of the elemental gas:
mole = mass/molar mass
Molar mass = mass/mole
Molar mass = 4.23g ÷ 0.151mol
Molar mass = 27.98g/mol
Answer:
3.45 moles Li contains 2.08 × 10 (to the power of)24 atoms .
Explanation:
The relationship between atoms and moles is:
1 mole atoms =
6.022 × 10 (to the power of)23
atoms
In order to determine how many atoms occupy a given number of moles, multiply the given moles by
6.022 × 10 (to the power of)23
atoms/mole
.
In the case of 3.45 moles lithium (Li):
3.45 mol Li × 6.022 × 10 (to the power of)23 atoms Li/ 1 mol Li =
2.08 × 10 (to the power of)24
atoms Li rounded to three
