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3 years ago

A corner test different weed killers on her along to see which kills the greatest number of dandelions............

1 answer:

7 0

Dependent variable: amount of dandelions killed by werd

Independent variable: health of dandelions/where they grew (if one is malnourished/older/dry it might be killed by the weed killer with more ease)

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I need part 1 and 2 please , just separate answers

Vladimir79 [104]

First, we have to remember the molarity formula:

$M=\text{ }\frac{moles\text{ of solute}}{L\text{ solution}}$

Part 1:

In this case, our solute is sodium nitrate (NaNO3), and we have the mass dissolved in water, then we have to convert grams to moles. For that, we need the molecular weight:

$M.W_{NaNO_3}=\text{ 23+14+16*3= 85 g/mol}$

Then, we calculate the moles present in the solution:

$3.976\text{ g NaNO}_3\text{ * }\frac{1\text{ mol}}{85\text{ g}}=\text{ 0.04678 mol NaNO}_3$

Now, we have the necessary data to calculate the molarity (with the solution volume of 200 mL):

$M=\frac{0.04678\text{ mol}}{200\text{ mL*}\frac{1\text{ L}}{1000\text{ mL}}}=\text{ 0.2339 M}$

The molarity of this solution equals 0.2339 M.

Part 2:

In this case, we have the same amount (in moles and mass) of sodium nitrate, but a different volume of solution, then we only have to change it:

$M=\text{ }\frac{0.04678\text{ mol}}{275\text{ mL *}\frac{1\text{ L}}{1000\text{ mL}}}=\text{ 0.1701 M}$

So, the molarity of this solution is 0.1701 M.

5 0

1 year ago

Which statement describes a property that is unique to metalloids?

hodyreva [135]

Answer:

Metalloids are semiconductive.

Explanation:

8 0

3 years ago

Read 2 more answers

A model of an ideal gas is shown here. A student designs an experiment to test the impact of increasing the pressure on the syst

k0ka [10]

A. As pressure on the gas increases, the volume and temperature will both decrease

6 0

3 years ago

The chemical equation shows iron(III) phosphate reacting with sodium sulfate. 2FePO4 + 3Na2SO4 Fe2(SO4)3 + 2Na3PO4 What is the t

slava [35]

<u>Answer:</u> The theoretical yield of iron(III) sulfate is 26.6 grams

<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)

Given mass of iron(III) phosphate = 20.00 g

Molar mass of iron(III) phosphate = 150.82 g/mol

Putting values in equation 1, we get:

$\text{Moles of iron(III) phosphate}=\frac{20g}{150.82g/mol}=0.133mol$

The given chemical equation follows:

$2FePO_4+3Na_2SO_4\rightarrow Fe_2(SO_4)_3+2Na_3PO_4$

As, sodium sulfate is present in excess. So, it is considered as an excess reagent.

Thus, iron(III) phosphate is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

2 moles of iron(III) phosphate produces 1 mole of iron(III) sulfate

So, 0.133 moles of iron(III) phosphate will produce = $\frac{1}{2}\times 0.133=0.0665moles$ of iron(III) sulfate

Now, calculating the mass of iron(III) sulfate from equation 1, we get:

Molar mass of iron(III) sulfate = 399.9 g/mol

Moles of iron(III) sulfate = 0.0665 moles

Putting values in equation 1, we get:

$0.0665mol=\frac{\text{Mass of iron(III) sulfate}}{399.9g/mol}\\\\\text{Mass of iron(III) sulfate}=(0.0665mol\times 399.9g/mol)=26.6g$

Hence, the theoretical yield of iron(III) sulfate is 26.6 grams

8 0

3 years ago

Which energy transformation occurs in an endothermic reaction

anygoal [31]

Answer:

heat energy

Explanation:

Chemical reactions often involve changes in energy due to the breaking and formation of bonds. Reactions in which energy is released are exothermic reactions, while those that take in heat energy are endothermic.

8 0

2 years ago