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2 years ago

A doorknob makes it easier for you to open doors because it is what type of simple machine?

Chemistry

1 answer:

vagabundo [1.1K]2 years ago

5 0

Answer: Wheel and Axle

Both of these work together to form a simple machine. You can't have one without the other.

If you try to turn just the axle itself, then you'll find it takes a lot of work. This is because the inertia of the axle wants to keep the object at rest. Also, you won't have a lot of torque due to the small radius compared to what a doorknob can offer.

Using a doorknob is like putting a (steering) wheel on an axle. This increases the radius and therefore increases the torque. You put in less work into the system and get more out of it.

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How can water dissovle many substances

11111nata11111 [884]

Answer: Polar molecules

Explanation: Water is able to dissolve many substances because of its polar molecules, The positive and negative ends of a water molecule attracts the molecules of other polar substances..

I'm pretty sure, idk college stuff

3 0

3 years ago

Read 2 more answers

A container is filled with helium gas. It has a volume of 2.25 liters and contains 9.00 moles of helium. How many moles of heliu

Darina [25.2K]

Answer: There are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.

Explanation:

Given: $V_{1}$ = 2.25 L, $n_{1}$ = 9.0 mol

$V_{2}$ = 1.85 L, $n_{2}$ = ?

Formula used to calculate the moles of helium are as follows.

$\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\$

Substitute the values into above formula as follows.

$\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\\frac{2.25 L}{9.0 mol} = \frac{1.85 L}{n_{2}}\\n_{2} = \frac{1.85 L \times 9.0 mol}{2.25 L}\\= 7.4 mol$

Thus, we can conclude that there are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.

7 0

2 years ago

112 g of aluminum carbide react with 174 g water to produce methane and aluminum hydroxide in the reaction shown below.

dolphi86 [110]

Answer: 4.999 moles of excess reactant will be left over.

Explanation:

Limiting reagent is defined as the reagent which is completely consumed in the reaction and limits the formation of the product.

Excess reagent is defined as the reagent which is left behind after the completion of the reaction.

The number of moles is defined as the ratio of the mass of a substance to its molar mass.

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

Given mass of aluminium carbide = 112 g

Molar mass of aluminium carbide = 143.96 g/mol

Putting values in equation 1:

$\text{Moles of aluminium carbide}=\frac{112g}{143.96g/mol}=0.778mol$

For the given chemical reaction:

$2Al_4C_3(s)+12H_2O(l)\rightarrow 3CH_4(g)+4Al(OH)_3(s)$

By the stoichiometry of the reaction:

2 moles of aluminium carbide reacts with 12 moles of water

So, 0.778 moles of aluminium carbide will react with = $\frac{12}{2}\times 0.778=4.668 mol$ of water

Given mass of water = 174 g

Molar mass of water = 18 g/mol

Putting values in equation 1:

$\text{Moles of water}=\frac{174g}{18g/mol}=9.667mol$

Moles of excess reactant (water) left = 9.667 - 4.668 = 4.999 moles

Hence, 4.999 moles of excess reactant will be left over.

8 0

2 years ago

The addition of a catalyst to a chemical reaction provides an alternate pathway that

Degger [83]

The addition of a catalyst to a chemical reaction provides an alternate pathway that catalysts lowers the activation energy.

4 0

3 years ago

Read 2 more answers

Scientists have been able to find a full record of Earth's fossil history, thus making the fossil record complete.

Arada [10]

Answer:

False

Explanation:

Few organisms were not preserved as well as others, and new fossils are found every day

5 0

2 years ago