Can someone list these in correct order? from least brigehst to brightest?

How many scientific methods

iogann1982 [59]

Answer:

There is one scientific method

it starts with an

OBSERVATION

then a HYPOTHESIS

which goes to planning, creating an EXPERIMENT

and finally a conclusion for your results

Explanation:

8 0

3 years ago

How much CO2 is produced from the combustion of a tank of propane C3H8? Assume the tank contains 9kgs of propane and the molecul

Zinaida [17]

Answer: The mass of carbon dioxide produced is 26.9 kg

Explanation:

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 propane = 9 kg = 9000 g (Conversion factor: 1 kg = 1000 g)

Molar mass of propane = 44.1 g/mol

Putting values in equation 1, we get:

$\text{Moles of propane}=\frac{9000g}{44.1g/mol}=204.08mol$

The chemical equation for the combustion of propane follows:

$C_3H_8+5O_2\rightarrow 3CO2+4H_2O$

By Stoichiometry of the reaction:

1 mole of propane produces 3 moles of carbon dioxide.

So, 204.08 moles of propane will produce = $\frac{3}{1}\times 204.08=612.24mol$ of carbon dioxide.

Now, calculating the mass of carbon dioxide by using equation 1, we get:

Molar mass of carbon dioxide = 44.01 g/mol

Moles of carbon dioxide = 612.24 moles

Putting values in equation 1, we get:

$612.24mol=\frac{\text{Mass of carbon dioxide}}{44.01g/mol}\\\\\text{Mass of carbon dioxide}=(612.24mol\times 44.01g/mol)=26944.7g=26.9kg$

Hence, the mass of carbon dioxide produced is 26.9 kg

3 0

3 years ago

What physical properties are important for the materials used to make mountain bikes?

Nikitich [7]

Answer:

density, yield strength, elasticity, Ductility, toughness, fatigue limit and corrosion resistance

7 0

3 years ago

A 250.0-mL buffer solution initially contains 0.025 mol of HCHO2 and 0.025 mol of NaHCO2. In order to adjust the buffer pH to 4.

worty [1.4K]

Answer:

We need to add NaOH to increase the pH decreasing the H⁺ concentration.

0.4g of NaOH must be added

Explanation:

The pKa of HCHO2 is 3.74. Using H-H equation the initial pH of the buffer is:

pH = pKa + log [NaHCO2] / [HCHO2]

pH = 3.74 + log [0.025mol] / [0.025mol]

pH = 3.74

The initial pH is 3.74, as we want a pH of 4.10, we need to add NaOH to increase the pH decreasing the H⁺ concentration.

Total moles of HCHO2-NaHCO2 buffer are:

0.025mol + 0.025mol =

0.050mol = [HCHO2] + [NaHCO2] (1)

Using H-H equation:

4.10 = 3.74 + log [NaHCO2] / [HCHO2]

0.36 = log [NaHCO2] / [HCHO2]

2.29087 = [NaHCO2] / [HCHO2] (2)

NaOH reacts with HCHO2 as follows:

NaOH + HCHO2 → NaHCO2 + H2O

Replacing (1) in (2):

2.29087 = 0.050 - [HCHO2] / [HCHO2]

2.29087[HCHO2] = 0.050 - [HCHO2]

3.29087[HCHO2] = 0.050

[HCHO2] = 0.015 moles

As HCHO2 decreases from 0.025 moles to 0.015 moles, the moles of NaOH added are 0.010moles.

The mass is:

0.010moles NaOH * (40g/mol) =

<h3>0.4g of NaOH must be added</h3>

5 0

3 years ago

For production of crude biodiesel from 250,000 kg/h rapeseed oil reacted with 75,000 kg/h ethanol and 250 kg/h potassium hydroxi

Tanya [424]

Answer:

will be 237,500 kg/h

Explanation:

The necessary ingredients to produce the biodiesel from the plant are: the plant, ethanol and the base. So after a period of 1 hour, the biodiesel that is going to be formed is 237, 500 kg/h.

Just apply the rule of three to the main source of biodiesel, that in this case is the rapessed plant and apply the 95 %. Ex:

Biodiesel = 0.95 x 250,000 = 237,500 kg/h

7 0

4 years ago

Can someone list these in correct order? from least brigehst to brightest?​

Can someone list these in correct order? from least brigehst to brightest?