Answer:
If each element can be identified by its spectrum then the composition of an unknown star can be determined
Explanation:
The chemical nature of the elements is that they absorb specific wavelength of light depending on their atom. By spectral analysis of the spectrum of emitted light by a body, the body's composition can therefore be determined. As such in order to determine the composition of distant bodies such as planets, stars and other celestial bodies scientists usually make use of spectroscopy.
Answer:
soft
Explanation:
it is white, it is sweet, and it also dissolves in water. it is not soft because sugar is actually sugar crystals.
Answer: Option (D) is the correct answer.
Explanation:
- A pure substance is defined as the substance that is made up of only one type of atom or only one type of molecule.
For example, is a molecule and it is a pure substance.
Also, substances that contain two or more different element which are chemically combined in a fixed ratio by mass are known as compounds. They are also pure substances.
A pure substance can only be separated by a chemical method and not by any physical method.
- A heterogeneous mixture is defined as the mixture which contains non-uniform composition of solute particles into the solution.
For example, mud dissolved in water.
It is not necessary that two or more substance present in a heterogeneous mixture should be of same phase.
Also, it is not necessary that combination of a liquid and a solid always results in a heterogeneous mixture.
If the solid is able to dissolve completely into the liquid then it will result in a homogeneous mixture.
- Whereas a homogeneous mixture is defined as the mixture which contains uniform distribution of solute particles into the solvent.
For example, salt dissolved in water is a homogeneous mixture.
Thus, we can conclude that the statement composition is uniform throughout a homogeneous mixture, is correct.
The covalent compound of c4i7 is 6
Answer:
(1) See below, (2) About 8.4 pH, (3) About 3.981 * 10⁻⁶ mol dm⁻³
Explanation:
1. A buffer is a solution that resist pH when adding a basic or acidic compound. It's purpose is to neutralize added acids and bases.
2. Remember that the formula for pH is -log [H+]. We have a 0.1 M solution of baking soda in water with [H+] of about 4.0 × 10⁻⁹. Therefore we can calculate the pH as follows...
pH = -log (4.0 × 10⁻⁹)
pH = -(-8.39794...) = (About) 8.4 pH of 0.1 M of baking soda
3. This question has a similar set up...
pH = -log [H+]
[H+] = inverse of log^- pH
[H+] = 10^-5.4 = (About) 3.981 10⁻⁶