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2 years ago

Please, What is the mass of oxygen in 72.0g of water? [ H= 1.0; O = 16.0]

1 answer:

5 0

Convert 72g of water into moles of water using molecular weights.

So water is H2O so add up those molecular weights (H=1 and O=16)

2(1)+(16) = 18 g/mol

Then convert so 72g / (18 g/mol) = 4 mol

Now you can convert mol of water to mol of oxygen. So 4 mol of water is 4 mol of oxygen. Then use oxygen molecular weight to find grams again.

4 mol oxygen * 16 g/mol = 64g of oxygen

If we were doing hydrogen instead of oxygen there would be 8 mol hydrogen in 4 mol of water (2 H’s in every H2O molecule) and since we have 74 grams and oxygen is 64 grams, Hydrogen should be 8 grams. Math to check below

8 mol hydrogen * 1 g/mol = 8g of hydrogen

It all adds to 72 so we are correct.

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To measure the amount of nickel in some industrial waste fluid, an analytical chemist adds sodium hydroxide solution to a sample

Cloud [144]

Answer:

The final balanced equation is

Ni2+ + 2NaOH --> Ni (OH)2 + 2Na+

Explanation:

It is given that sodium hydroxide is added to collect the solid nickel(II) hydroxide product

The empirical equation for this statement is

Ni2+ + NaOH --> Ni (OH)2 + Na+

We will first balance the hydroxide molecule. On the right side there are two OH molecules.

Thus, on the left side we will take 2 sodium hydroxide

Ni2+ + 2NaOH --> Ni (OH)2 + Na+

Now we will balance the sodium ion which are 2 in numbers on the left side and 1 on the right side

Ni2+ + 2NaOH --> Ni (OH)2 + 2Na+

So, the final balanced equation is

Ni2+ + 2NaOH --> Ni (OH)2 + 2Na+

8 0

2 years ago

Is food coloring in water a mixture or pure substance

kkurt [141]

Answer:

In this experiment, different solutions are made by mixing water with different colors and amounts of food coloring. Students should notice that once the water and colors are mixed together, the liquid looks the same throughout. It is a solution—a homogeneous mixture

Explanation:

8 0

3 years ago

Read 2 more answers

Both white phosphorus and red phosphorus are made up only of phosphorus atoms.Does this mean they are both pure substances? Coul

choli [55]

True, both of the red and white phosphorus is a pure substance.

Both red and white phosphorus is made of phosphor element but they have a different structure which causes them to have a different color. This phenomenon called allotropes when a chemical element has two or more different form.They are not compounds as they are only made of phosphorus. A compound should be made by at least two different elements.

4 0

3 years ago

Sam believes the rock is more denser than the pencil. He measured the mass of the rock to be 8.5 grams and volume to be 4.5mL. H

mezya [45]

Answer:

Rock

Explanation:

Let's calculate the density of each object:

Rock:

$Density = \frac{mass}{volume}=\frac{8.5\ g}{4.5\ mL}=1.9\ g/mL$

Pencil:

$Density = \frac{mass}{volume}=\frac{2.4\ g}{4.5\ mL}=0.53\ g/mL$

Therefore the rock is denser.

6 0

2 years ago

Use the drop-down menus to answer the questions. Which type of radioactive decay produces particles with a positive charge and v

Alexus [3.1K]

Answer:

beta, gamma, gamma

Explanation:

I just guessed and got the answers ur welcome 2020 team work.

8 0

3 years ago