Is wastewater physical properties or chemical

Balance the following half reaction in basic conditions. Then, indicate the coefficients for H2O and OH– for the balanced half r

Ugo [173]

Answer:

The ballance half reactions are:

Mg²⁺ + 2e⁻ → Mg

6OH⁻ + Si → SiO₃²⁻ + 4e⁻ + 3 H₂O

Coefficients for H2O and OH– are 3 for H₂O (in products side) and 6 for OH⁻ (in reactants side)

Explanation:

Si (s) + Mg(OH)₂ (s) → Mg (s) + SiO₃²⁻ (aq)

Let's see the oxidations number.

As any element in ground state, we know that oxidation state is 0, so Si in reactants and Mg in products, have 0.

Mg in reactants, acts with +2, so the oxidation number has decreased.

This is the reduction, so it has gained electrons.

Si in reactants acts with 0 so in products we find it with +4. The oxidation number increased it, so this is oxidation. The element has lost electrons.

Let's take a look to half reactions:

Mg²⁺ + 2e⁻ → Mg

Si → SiO₃²⁻ + 4e⁻

In basic medium, we have to add water, as the same amount of oxygen we have, IN THE SAME SIDE. We have 3 oxygens in products, so we add 3 H₂O and in the opposite site we can add OH⁻, to balance the hydrogen. The half reaciton will be:

6OH⁻ + Si → SiO₃²⁻ + 4e⁻ + 3 H₂O

If we want to ballance the main reaction we have to multiply (x2) the half reaction of oxidation. So the electrons can be ballanced.

2Mg²⁺ + 4e⁻ → 2Mg

Now, that they are ballanced we can sum the half reactions:

2Mg²⁺ + 4e⁻ → 2Mg

6OH⁻ + Si → SiO₃²⁻ + 4e⁻ + 3 H₂O

2Mg²⁺ + 4e⁻ + 6OH⁻ + Si → 2Mg + SiO₃²⁻ + 4e⁻ + 3 H₂O

7 0

3 years ago

How many bromine atoms are present in 37.9 g of CH2Br2?

VARVARA [1.3K]

Answer:

The answer to your question is: 6.55 x 10 ²³ atoms of Br

Explanation:

CH2Br2 = 37.9 g

MW CH2Br2 = (12 x 1) + (2 x 1) + (80 x 2) = 174 g

174 g of CH2Br2 ------------------ 160 g of Br2

37.9 g of CH2Br2 --------------- x

x = 37.9 x 160/174 = 34.85 g of Br

1 mol of Br ----------------- 160 g Br2

x ---------------- 174 g Be2

x = 174 x 1 /160 = 1.088 mol of Br2

1 mol of Br ----------------- 6.023 x 10 ²³ atoms

1.088 mol of Br ------------- x

x = 1.088 x 6.023 x 10 ²³ / 1 = 6.55 x 10 ²³ atoms

4 0

2 years ago

An average person expends about 845 kilojoules of energy per hour of walking. Suppose a person eats 2 baked potatoes with butter

ExtremeBDS [4]

Answer:

$\large\boxed{2hours}$

Explanation:

You will need to use the conversion between food calories, calories and joules.

$1\text { nutritional calorie }= 1,000cal\\ \\ 1cal=4.184joule$

From a nutritional table (from the internet) you can obtain the amount of nutritional calories for each type macronutrient: carbohydrates, protein, and fat.

Macronutrient food calories

Carbohydrate 4 cal/g

Protein 4 cal/g

Fat 9 cal/g

To convert food calories to regular calories, mutiply by the conversion factor:

$1=1,000cal/\text{nutritional calorie}$

Macronutrient calories

Carbohydrate 4,000 cal/g

Protein 4,000 cal/g

Fat 9,000 cal/g

To convert regular calories to joules, multiply by the conversion factor:

$1=4.184 joule/1cal$

Macronutrient energy in joules

Carbohydrate 16,736 joule/g

Protein 16,736 joule/g

Fat 37,656 joule/g

Now you can multiply the grams of each macronutrient in one potato by its energy content:

Macronutrient energy/gram × grams = total energy

Carbohydrate 16,736 joule/g × 37 g = 619,232 joules

Protein 16,736 joule/g × 4.3 g = 71,968.8 joules

Fat 37,656 joule/g × 4 g = 150,624 joules

Total = 619,232 joules + 71,968.8 joules + 150,624 joules = 841,820.8 joules.

Since they are two potatoes, multiply by 2: × 841,820.8 joules = 1,683,641.6 joules.

Divide by 1,000 to convert to kilojoules = 1,683.64 kilojoules

Divide the total energy from the two potatoes by the energy that an average person expend per hour of walking (845 kilojoules of energy per hour):

$1,683.64kilojoules/845kilojouesl/hour=1.99hours\approx 2hours$

7 0

3 years ago

Mg(OH)2+2 HCI = MgCI2+ H2O

In-s [12.5K]

Answer:

Mg(OH)2 + 2HCI ⇒ MgCI2 + 2H2O

Explanation:

In order to balance a chemical equation you need to make sure both sides of the equations are equal.

Mg(OH)2 + 2HCI = MgCI2 + H2O

Mg = 1

Oh = 2

HCI = 2

Products:

Mg = 1

CI = 2

H = 2

O = 1

2H20 = 1 × 2 = 2

2 × 2 = 4

2HCI

1 × 2 = 2

Mg(OH)2 + 2HCI ⇒ MgCI2 + 2H2O

Hope this helps.

7 0

2 years ago

What are the starting materials in a chemical reaction called?

Irina18 [472]

A chemical reaction is the process in which atoms present in the starting substances rearrange to give new chemical combinations present in the substances formed by the reaction. These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products.

8 0

3 years ago