What is the name of the supercontinent that existed 245 million years ago

hichkok12 [17]

B, turns red litmus paper to blue

5 0

3 years ago

What amount of energy is required to change a spherical drop of water with a diameter of 1.80 mm to three smaller spherical drop

Gekata [30.6K]

This is a straightforward question related to the surface energy of the droplet.

You know the surface area of a sphere is 4π r² and its volume is (4/3) π r³. 

With a diameter of 1.4 mm you have an original droplet with a radius of 0.7 mm so the surface area is roughly 6.16 mm² (0.00000616 m²) and the volume is roughly 1.438 mm³. 

The total surface energy of the original droplet is 0.00000616 * 72 ~ 0.00044 mJ 

The five smaller droplets need to have the same volume as the original. Therefore 

5 V = 1.438 mm³ so the volume of one of the smaller spheres is 1.438/5 = 0.287 mm³. 

Since this smaller volume still has the volume (4/3) π r³ then r = cube_root(0.287/(4/3) π) = cube_root(4.39) = 0.4 mm. 

Each of the smaller droplets has a surface area of 4π r² = 2 mm² or 0.0000002 m². 

The surface energy of the 5 smaller droplets is then 5 * 0.000002 * 72.0 = 0.00072 mJ 
From this radius the surface energy of all smaller droplets is 0.00072 and the difference in energy is 0.00072- 0.00044 mJ = 0.00028 mJ. 

Therefore you need roughly 0.00028 mJ or 0.28 µJ of energy to change a spherical droplet of water of diameter 1.4 mm into 5 identical smaller droplets.

7 0

3 years ago

A synthesis reaction takes place when carbon monoxide (CO) and hydrogen gas (H2) react to form methanol (CH3OH). How many grams

kakasveta [241]

Answer:

A. 3.2grams

Explanation:

First we need to get the chemical equation for this reaction:

CO + H₂ → CH₃OH

We then need to balance the equation:

CO + 2H₂ → CH₃OH

Our next step is to first convert our given into moles. We do this by figuring out first how many grams of each substance there are in 1 mole by adding up the atomic mass of each element in each substance.

Carbon(1) Oxygen(1)

CO = 12.011(1) + 15.999(1) = 28.01 g/mole

Hydrogen(2)

H₂ = 1.008(2) = 2.016g/mole

We can then use this to determine how many moles of each reactant we have given the mass.

$CO = 2.8g\\2.8g\times\dfrac{1mole}{28.01g}=0.1moles\\\\H_{2}=0.50g\\\\0.50g\times\dfrac{1mole}{2.016g}=0.469moles$

So here we have our new given:

0.1 moles of CO

0.496 moles of H₂

We then need to determine how much product we produce with our given.

According to our chemical equation we can assume that:

For every 1 mole of CO we can produce 1 mole of CH₃OH

Fore every 2 moles of H₂ we can produce 1 mole of CH₃OH

Using this ratio we can determine how much product each reactant will produce by using the ratios:

$0.1 moles of CO\times\dfrac{1moleofCH_{3}OH}{1moleofCO}=0.1moles of CH_{3}OH\\\\ 0.496molesofH_{2}\times\dfrac{1moleofCH_{3}OH}{2molesofH_{2}}=0.248molesofCH_{3}OH$

Now notice that they are not equal. The reactant that produces the least amount of product will be our limiting reactant. The limiting reactant determines the amount of product that is produced, because once it is completely used up, the reaction stops. So in this case, the amount of CH₃OH that is produced is 0.10 moles.

Now we need to figure out how many this is in grams. To do that we need to find out how many grams of CH₃OH there are in 1 mole of CH₃OH.

Carbon (1) Hydrogen(4) Oxygen(1)

CH₃OH = 12.001(1) + 1.008(4) + 15.999(1)

= 12.001 + 4.032 + 15.999 = 32.032g/mole

We then use this for converting:

$0.10 moles\times\dfrac{32.032g}{1mole}=3.2032g$

So the reaction will produce 3.2032g of CH₃OH or 3.2g of CH₃OH

3 0

3 years ago

What is the number of ions in 0.20 mol of (NH4)3PO4?

neonofarm [45]

Answer:

hey, it's B

Explanation:

1 mol= 6.022×10²³ ions

0.2 mol= 0.2 × 6.022 × 10²³ ions

4 0

2 years ago

Which starch solution will decrease in volume as osmosis occurs?

iogann1982 [59]

For the following question(s), consider a 4% starch solution and a 10% starch solution separated by a semipermeable membrane.

Which of the following also occurs in this system?
There is a net flow of water from the 4% starch solution into the 10% starch solution

7 0

3 years ago