Answer:
37.5 g NaCl
Explanation:
Step 1: Given data
- Concentration of NaCl: 15.0% m/m
- Mass of the solution: 250.0 g
Step 2: Calculate how many grams of NaCl are in 250.0 g of solution
The concentration of NaCl is 15.0% by mass, that is, there are 15.0 g of NaCl every 100 g of solution.
250.0 g Solution × 15.0 g NaCl/100 g Solution = 37.5 g NaCl
Answer:
It will increase the rate of chemical weathering.
Explanation:
Weathering is the breaking down or dissolving of rocks and minerals on the surface of the earth into smaller grains or soil.
Weathering can occur either by biological, chemical or mechanical means.
When mechanical (or physical) weathering breaks a small boulder into pieces, this will lead to an increase in the rate of chemical weathering.
Chemical weathering involves chemical reactions or changes that occur in rocks which results in changes in their size and composition. This chemical reactions that breaks down rocks include hydrolysis by water and oxidation by oxygen. <em>The rate of chemical reactions increase with increase in surface area of the substances reacting.</em>
When the boulder is broken into smaller pieces, it exposes a larger area of these rocks to the chemical reactions that weather rocks. For example, a larger surface of the rock may be exposed to water result in faster reaction of the rock salts with water, and thus, the rock particles are broken down faster.
Answer:
No
Explanation:
We cannot identify an atom without knowing numbers of protons in the atom.
The number of neutrons is the amount of neutrally charged particles in an atom. These subatomic particles occupy the dense nucleus with the protons.
- To determine an atom, we use their atomic numbers.
- Atomic number is the number of protons in an atom.
- Protons are the positively charged particles in the atom.
- The periodic table of elements is arranged by the atomic number of an element.
Answer:
81.97 g of NaAl(OH)₄
Solution:
The reaction for the preparation of Sodium Aluminate from Aluminium Metal and NaOH is as follow,
2 NaOH + 2 Al + 6 H₂O → 2 NaAl(OH)₄ + 3 H₂
According to this equation,
2 Moles of NaOH produces = 163.94 g (2 mole) of NaAl(OH)₄
So,
1 Mole of NaOH will produce = X g of NaAl(OH)₄
Solving for X,
X = (1 mol × 163.94 g) ÷ 2 mol
X = 81.97 g of NaAl(OH)₄
The symbol of an isotope is:
A - the mass number
Z - the atomic number
X - the symbol of an element
The symbol of oxygen is O.
The atomic number is the same for all isotopes of one element. For oxygen it's 8, because every atom of oxygen has 8 protons in its nucleus.
The mass number is the number of nucleons (protons + neutrons) in the nucleus of an atom, and it's given in the name of an isotope. Oxygen-16 has the mass number 16, oxygen-17 has the mass number 17, oxygen-18 has the mass number 18.
Oxygen-16:
Oxygen-17:
Oxygen-18:
