Answer:
All colors except blue are absorbed while blue is reflected. We
only see blue
Explanation:
When you go and see something blue as the sky, all of the colors are absorbed except blue. That is how we see colors
Answer:
191.6 g of CaCl₂.
Explanation:
What is given?
Mass of HCl = 125.9 g.
Molar mass of CaCl₂ = 110.8 g/mol.
Molar mass of HCl = 36.4 g/mol.
Step-by-step solution:
First, we have to state the chemical equation. Ca(OH)₂ react with HCl to produce CaCl₂:
Now, let's convert 125.9 g of HCl to moles using the given molar mass (remember that the molar mass of a compound can be found using the periodic table). The conversion will look like this:
Let's find how many moles of CaCl₂ are being produced by 3.459 moles of HCl. You can see in the chemical equation that 2 moles of HCl reacted with excess Ca(OH)₂ produces 1 mol of CaCl₂, so we state a rule of three and the calculation is:
The final step is to find the mass of CaCl₂ using the molar mass of CaCl₂. This conversion will look like this:
The answer would be that we're producing a mass of 191.6 g of CaCl₂.
This statment is false, the pen on a seismograph does not swing freely.
Answer:
Explanation:
An atom is the smallest unit of an element that can take part in a chemical reaction. Atoms are made up of protons, neutrons and electrons. Atoms can exist as a monoatomic (such as in the case of Helium, Xenon and Neon) or as diatomic (such as in the case of oxygen and nitrogen). Atoms take part in a chemical reaction and there reactivity varies among themselves.
From the above, it can be deduced that atoms have protons, neutrons and electrons. The number of protons (which is positively charged) of an atom determines it's position on the periodic table because elements in the periodic table are arranged according to the number of protons (called atomic number). The electron(s) present in the outermost shell of each atom (called valence electrons) determines there chemical reactivity. What happens here is that, all atoms (except noble gases) want to achieve there duplet or octet configuration so as to become stable. This octet configuration means they want to have there outermost shell completely filled (with eight electrons or two electrons for duplet). They usually achieve this configuration by taking part in chemical reactions. Thus, when an atom has just one electron in it's outermost shell, it becomes easy to lose it to another atom by way of interacting with it in a chemical reaction. When it loses this single electron (valence electron) in it's outermost shell, it becomes stable with the inner completely filled shell (that would be the new outermost shell). Examples include Lithium, sodium and potassium. Sodium (with eleven electrons and three shells) would lose the single electron in it's outermost shell so as to have just two shells with the second shell completely filled with eight electrons. Thus, <u>the more the valence electron to be lost to achieve the octet structure</u>,<u> the lesser the reactivity of the atom</u>.
Also, an atom that has just one electron to complete it's own outermost shell and thus achieve it's octet structure is also highly reactive. This is also because it is easy for this atom to receive a single electron and become completely filled. Examples include chlorine, fluorine and iodine. Fluorine (with nine electrons and two shells) will easily accept one more electron so as to achieve it's octet structure with a completely filled outermost shell (of eight electrons). Thus, <u>the lesser the electrons to be gained to achieve the octet configuration, the higher the chemical reactivity of such atoms</u>. Noble gases have extremely low or no reactivity at all for this reason because it has a completely filled outermost shell (no losing or donating).
It should also be noted that metals (which are found on the left of the periodic table) exist as monoatomic while gases (which are found on the right), with the exception of noble gases, are mostly diatomic.
Answer:
If a reaction produces a gas such as oxygen or carbon dioxide, there are two ways to measure the reaction rate: using a gas syringe to measure the gas produced, or calculating the reduction in the mass of the reaction solution.
