Helllpppppp pretty please

Zachary adds 26.64 g to 12.557 g. How many significant figures should his answer have?

asambeis [7]

This answer should have four signifigant features

Explanation:

I had this on a test and got it right :D

5 0

3 years ago

Read 2 more answers

Why do hurricanes form over warm oceans rather than cold oceans?

Setler [38]

Because the heat of the ocean mixed with the cold air above the ocean causes a hurricane

6 0

3 years ago

Which is true about covalent compounds?have a high melting pointconduct electricity when dissolved in waterhave a low boiling po

iris [78.8K]

The correct answer from the choices given is the third option. Covalent compounds have low boiling points. Also, their melting points are low. Covalent bonds have relatively low attractions which results to these properties. The bonds are easily broken by taking energy or adding energy.

8 0

2 years ago

Hydrogen fluoride is used in the manufacture of Freons (which destroy ozone in the stratosphere) and in the production of alumin

Lerok [7]

<u>Answer:</u> The percentage yield of HF is 73.36 %

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ....(1)

For calcium fluoride:

Given mass of calcium fluoride = 6.25 kg = 6250 g (Conversion factor: 1 kg = 1000 g)

Molar mass of calcium fluoride = 78.07 g/mol

Putting values in above equation, we get:

$\text{Moles of calcium fluoride}=\frac{6250g}{78.07g/mol}=80.05mol$

For the given chemical reaction:

$CaF_2+H_2SO_4\rightarrow CaSO_4+2HF$

By Stoichiometry of the reaction:

1 mole of calcium fluoride produces 2 moles of hydrofluoric acid

So, 80.05 moles of calcium fluoride will produce = $\frac{2}{1}\times 80.05=160.1mol$ of hydrofluoric acid

Now, calculating the theoretical yield of hydrofluoric acid using equation 1, we get:

Moles of of hydrofluoric acid = 160.1 moles

Molar mass of hydrofluoric acid = 20.01 g/mol

Putting values in equation 1, we get:

$160.1mol=\frac{\text{Theoretical yield of hydrofluoric acid}}{20.01g/mol}=3203.6g=3.20kg$

To calculate the percentage yield of hydrofluoric acid, we use the equation:

$\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

Experimental yield of hydrofluoric acid = 2.35 kg

Theoretical yield of hydrofluoric acid = 3.20 kg

Putting values in above equation, we get:

$\%\text{ yield of hydrofluoric acid}=\frac{2.35g}{3.20g}\times 100\\\\\% \text{yield of hydrofluoric acid}=73.36\%$

Hence, the percentage yield of HF is 73.36 %

4 0

2 years ago

What would happen to the temreture if there was a sudden icrease in the amount of greenhouse gasses

Rus_ich [418]

Answer:

The higher concentrations of greenhouse gases—and carbon dioxide in particular—is causing extra heat to be trapped and global temperatures to rise.

4 0

1 year ago

Helllpppppp pretty please​

Helllpppppp pretty please