Answer:
0.5 × 10²³ atoms of iodine
Explanation:
Given data:
Mass of calcium iodide = 12.75 g
Number of atoms of iodine = ?
Solution:
First of all we will calculate the number of moles of calcium iodide.
Number of moles = mass/ molar mass
Number of moles = 12.75 g/ 293.9 g/mol
Number of moles = 0.04 mol
In one mole of calcium iodide there are two moles of iodine.
Thus in 0.04 moles:
0.04 mol × 2 = 0.08 moles of iodine
Now we will use the Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
0.08 moles of iodine × 6.022 × 10²³ atoms / 1 mol
0.5 × 10²³ atoms of iodine.
Answer:
Below 0° degrees Celcius
Explanation:
For deposition (gas to solid) to happen, the temperature has to be below 0° Celsius. If so, deposition occurs, and ice crystals form.
Answer:
0.87 pg
Explanation:
<em>GenAlex Medical, a leading manufacturer of medical laboratory equipment, is designing a new automated system that can detect normal levels of dissolved triiodothyronine (230. to 660 pg/dL), using a blood sample that is as small as 380 μL. Calculate the minimum mass in picograms of triiodothyronine that the new system must be able to detect. Be sure your answer has the correct number of significant digits.</em>
Step 1: Convert 380 μL to deciliters
We will use the following conversion factors.
380 μL × 1 L/10⁶ μL × 10 dL/1 L = 3.8 × 10⁻³ L
Step 2: Calculate the minimum mass of triiodothyronine that can be found in a 3.8 × 10⁻³ L blood sample
Since we are looking for the minimum mass, we will use the lower limit of the concentration interval (230. pg/dL).
3.8 × 10⁻³ L × 230. pg/dL = 0.87 pg
Answer:
They have mobile charged particles.
Explanation:
Plasma refers to very hot matter such that the electrons in matter are ripped away from the atoms leading to the formation of an ionized gas.
We know that the carriers of electricity are charged particles. Any state of matter that has an abundance of charge carriers will definitely be a good conductor of electricity.
Therefore, plasmas are good conductors of electricity because they have a lot of mobile charged particles.
Answer:-A. It is less than 890 kJ/mol because the amount of energy required to break bonds is less than the amount of energy released in forming bonds.
Explanation: Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and 
for the reaction comes out to be positive.
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and for the reaction comes out to be negative.
In the formation of new bonds more energy is released than is required to break the existing bonds, heat is released.
In the formation of bonds less energy is released than is required to break the existing bonds, heat is absorbed.
