Answer:
Na₂CO₃•H₂O
Explanation:
After it is heated, the remaining mass is the mass of sodium carbonate.
30.2 g Na₂CO₃
Mass is conserved, so the difference is the mass of the water:
35.4 g − 30.2 g = 5.2 g H₂O
Convert masses to moles:
30.2 g Na₂CO₃ × (1 mol Na₂CO₃ / 106 g Na₂CO₃) = 0.285 mol Na₂CO₃
5.2 g H₂O × (1 mol H₂O / 18.0 g H₂O) = 0.289 mol H₂O
Normalize by dividing by the smallest:
0.285 / 0.285 = 1.00 mol Na₂CO₃
0.289 / 0.285 = 1.01 mol H₂O
The ratio is approximately 1:1. So the formula of the hydrate is Na₂CO₃•H₂O.
Answer:
V = 27.98 L
Explanation:
Given data:
Mass of CO₂ = 33.0 g
Pressure = 500 torr
Temperature = 27°C
Volume occupied = ?
Solution:
Number of moles of CO₂:
Number of moles = mass/molar mass
Number of moles = 33.0 g/ 44 g/mol
Number of moles = 0.75 mol
Volume of CO₂:
PV = nRT
R = general gas constant = 0.0821 atm.L/ mol.K
Now we will convert the temperature.
27+273 = 300 K
Pressure = 500 /760 = 0.66 atm
By putting values,
0.66 atm×V = 0.75 mol × 0.0821 atm.L/ mol.K × 300 K
V = 18.47 atm.L/0.66 atm
V = 27.98 L
Answer:
The correct option is: bent 109°
Explanation:
Covalent molecules are the molecules in which the atoms are linked by covalent bonds. The electrons involved in the formation of a covalent bond are known as shared pair or <u>bond pair of electrons</u>.
The three-dimensional arrangement of the atoms of a molecule in space is known its molecular structure or geometry.
<u>Given molecule</u>: XY₂, having two lone pairs around the central atom X.
Since the molecule XY₂ has <u>two lone pairs</u> and <u>two bond pairs</u> of electrons. Therefore according to the VSEPR theory, the given molecule has a <u>bent molecular geometry with 109° bond angle.</u>
<u>Answer:</u> The correct answer is Option A.
<u>Explanation:</u>
A catalyst is defined as the substance which increases the rate of the reaction without actually participating in the reaction.
This substance decreases the activation energy of the reactants, so as to proceed the reaction at a faster rate by increasing their effective collisions.
It does not affect the concentration of the reactants.
For the given reaction:
If we add NO, which is acting as a catalyst will increase the rate of the reaction to produce the products which is 
Hence, the correct answer is Option A.
Answer:
Chemical change
Step-by-step explanation:
A change in colour indicates that a new substance with different properties (colour) has been formed. This is a chemical change.
A. is <em>wrong</em>. A physical change does not usually cause a change in colour.
B. is <em>wrong</em>. No new gas or solid was formed,
C. is <em>wrong</em>. There is a colour change, not a temperature change.
