The mass number = protons + neutrons. Bromine has a mass number of 80<span> and 35 protons so </span>80<span>-35 = </span>45<span> neutrons. b) How many electrons does the neutral atom of bromine have? The neutral atom of bromine has 35 electrons because the number of electrons equals the number of protons.</span>
Answer:
A. The total mass of the reactants in a reaction equals the total mass of the product(s).
Explanation:
The law of conversation of matter tells us that in a chemical reaction, matter is never created or destroyed, it's simply converted from one form to another. So the mass of reactants should always equal the mass of the products in a chemical reaction.
Answer:
Here's what I get
Explanation:
1. Sugar
(a) Dissolving in water
The white solid dissolves in water to give a colourless solution. There is no evidence that a new substance is being produced.
(b) Addition of sodium hydroxide
Adding the colourless solution of sodium hydroxide to the colourless sugar solution gives a colourless solution. There is no evidence that a new substance is being produced.
2. Magnesium sulfate
(a) Dissolving in water
The colourless crystals dissolve in water to give a colourless solution. There is no evidence that a new substance is being produced.
(b) Addition of sodium hydroxide
Adding the colourless solution of sodium hydroxide to the colourless solution of magnesium sulfate gives a white precipitate (see image). This is evidence that a new substance is being produced.
Explanation:
The balanced equation of the reaction is given as;
Mg(OH)2 (s) + 2 HBr (aq) → MgBr2 (aq) + 2 H2O (l)
1. How many grams of MgBr2 will be produced from 18.3 grams of HBr?
From the reaction;
2 mol of HBr produces 1 mol of MgBr2
Converting to masses using;
Mass = Number of moles * Molar mass
Molar mass of HBr = 80.91 g/mol
Molar mass of MgBr2 = 184.113 g/mol
This means;
(2 * 80.91 = 161.82g) of HBr produces (1 * 184.113 = 184.113g) MgBr2
18.3g would produce x
161.82 = 184.113
18.3 = x
x = (184.113 * 18.3 ) / 161.82 = 20.8 g
2. How many moles of H2O will be produced from 18.3 grams of HBr?
Converting the mass to mol;
Number of moles = Mass / Molar mass = 18.3 / 80.91 = 0.226 mol
From the reaction;
2 mol of HBr produces 2 mol of H2O
0.226 mol would produce x
2 =2
0.226 = x
x = 0.226 * 2 / 2 = 0.226 mol
3. How many grams of Mg(OH)2 are needed to completely react with 18.3 grams of HBr?
From the reaction;
2 mol of HBr reacts with 1 mol of Mg(OH)2
18.3g of HBr = 0.226 mol
2 = 1
0.226 = x
x = 0.226 * 1 /2
x = 0.113 mol
Answer:
.056
Explanation:
H+=10^-pH
- Hope that helps! Please let me know if you need further explanation.
