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2 years ago

14

2. When do chemical reactions happen?

1 answer:

Alenkinab [10]2 years ago

7 0

Either the 1or3answer

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Hanna hypothesizes that granite is denser than sandstone. How can Hanna test her hypothesis?

kherson [118]

To test if the hypothesis is correct, a good way is to think of it this way:
Density = mass/volume, right?
Calculate the mass and volume of each and do the equation; this will test your hypothesis.
You will be left with the density of each. But, make sure that the sample sizes are the same (controlled variable) otherwise it will be an unfair test.

5 0

2 years ago

The rock was white and black speckled with a density of 2.6 g/mL. Physical or chemical property?

stepladder [879]

Answer:

Chemical

Explanation:

7 0

2 years ago

A gas used to extinguish fires is composed of 75 % CO2 and 25 % N2. It is stored in a 5 m3 tank at 300 kPa and 25 °C. What is th

tatyana61 [14]

Answer : The partial pressure of the $CO_2$ in the tank in psia is, 32.6 psia.

Explanation :

As we are given 75 % $CO_2$ and 25 % $N_2$ in terms of volume.

First we have to calculate the moles of $CO_2$ and $N_2$ .

$\text{Moles of }CO_2=\frac{\text{Volume of }CO_2}{\text{Volume at STP}}=\frac{75}{22.4}=3.35mole$

$\text{Moles of }N_2=\frac{\text{Volume of }N_2}{\text{Volume at STP}}=\frac{25}{22.4}=1.12mole$

Now we have to calculate the mole fraction of $CO_2$ .

$\text{Mole fraction of }CO_2=\frac{\text{Moles of }CO_2}{\text{Moles of }CO_2+\text{Moles of }N_2}$

$\text{Mole fraction of }CO_2=\frac{3.35}{3.35+1.12}=0.75$

Now we have to calculate the partial pressure of the $CO_2$ gas.

$\text{Partial pressure of }CO_2=\text{Mole fraction of }CO_2\times \text{Total pressure of gas}$

$\text{Partial pressure of }CO_2=0.75mole\times 300Kpa=225Kpa=225Kpa\times \frac{0.145\text{ psia}}{1Kpa}=32.625\text{ psia}$

conversion used : (1 Kpa = 0.145 psia)

Therefore, the partial pressure of the $CO_2$ in the tank in psia is, 32.6 psia.

3 0

2 years ago

What is the name of P517

saul85 [17]

Answer:

Ryobi P517 18V Lithium Ion Cordless Brushless 2,900 SPM Reciprocating Saw w/ Anti-Vibration Handle and Tool-Less Blade Changing

Explanation:

8 0

2 years ago

What is the density (g / mL) of a substance that has a mass of 8.11 g and, when placed into a graduated cylinder, causes the wat

MAXImum [283]

Answer:

<h3>The answer is 0.42 g/mL</h3>

Explanation:

The density of a substance can be found by using the formula

$density = \frac{mass}{volume} \\$

From the question

mass = 8.11 g

volume = final volume of water - initial volume of water

volume = 44.72 - 25.26 = 19.46 mL

We have

$density = \frac{8.11}{19.46} \\ = 0.416752312...$

We have the final answer as

<h3>0.42 g/mL</h3>

Hope this helps you

8 0

2 years ago