What has fewer organisms then a domain but it also has more organisms then a phylum

Human use of groundwater has _______ over time.

Harman [31]

Increased is the answer

7 0

3 years ago

When active metals such as magnesium are immersed in acid solution, hydrogen gas is evolved. Calculate the volume of H2(g) at 30

V125BC [204]

Answer:

The volume of H₂ (g) obtained is 22.4L

Explanation:

First of all, think the reaction:

2HCl (aq) + Zn (s) → ZnCl₂ (aq) + H₂ (g)

You have to add a 2, in the HCl to get ballanced.

Now we should know how many moles of each reactant, do we have.

Volume . Molarity = moles

Notice that volume is in mL, so I must convert to L.

275 mL = 0.275L

0.275L . 0.725mol/L = 0.2 moles of HCl

Molar mass of Zn: 65.41 g/m

50 g / 65.41 g/m = 0.764 moles

Ratio between reactants is 2:1, so I need the double of moles of HCl to react, and a half moles of Zn to react.

My limiting reactant is the HCl, for 0.764 moles of Zinc, I need 1.528 (0.764 .2) of HCl, and I only have 0.2 moles.

Ratio between HCl and H₂ is 1:1, so 0.2 HCl make 0.2 moles of gas

Now apply the Ideal Gas Law, to find out the volume

P. V = n . R . T

2 atm . V = 0.2 mol . 0.08206L atm/K mol . 273K

V = (0.2 mol . 0.08206L atm/K mol . 273K ) / 2 atm

V = 2.24 L

4 0

3 years ago

How many variables are there in science

Sedaia [141]

There are three variables independent, dependent ,and controlled

7 0

3 years ago

Write a balanced equation for the complete oxidation reaction that occurs when ethane burns in air

damaskus [11]

<h3>Balanced equation : 2C₂H₆ (g) + 7O₂ (g) ⟶ 4CO₂ (g) + 6H₂O (ℓ)</h3><h3>Further explanation</h3>

Alkanes are saturated hydrocarbons that have single bonds in chains

General formula for alkanes :

$\tt \large{\bold{C_nH_{2n+2}}$

Hydrocarbon combustion reactions (specifically alkanes)

$\large {\box {\bold{C_nH _ (_2_n _ + _ 2_) + \dfrac {3n + 1} {2} O_2 \Rightarrow nCO_2 + (n + 1) H_2O}}}$

So that the burning of ethane with air (oxygen):

$\tt C_2H_6+\dfrac{7}{2}O_2\rightarrow 2CO_2+3H_2O$

2C₂H₆ (g) + 7O₂ (g) ⟶ 4CO₂ (g) + 6H₂O (ℓ)

or we can use mathematical equations to solve equilibrium chemical equations by giving the coefficients for each compound involved in the reaction

C₂H₆ (g) + aO₂ (g) ⟶ bCO₂ (g) + cH₂O (ℓ)

C : left 2, right b ⇒ b=2

H: left 6, right 2c⇒ 2c=6⇒ c= 3

O : left 2a, right 2b+c⇒ 2a=2b+c⇒2a=2.2+3⇒2a=7⇒a=7/2

6 0

4 years ago

What is the ability to transfer thermal energy to something else

Fofino [41]

Answer:

.Heat energy can be transferred from one object to another. The transfer or flow due to the difference in temperature between the two objects is called heat.

Explanation:

The transfer of thermal energy is called heat. In this process, thermal energy moves through a substance. For example, an ice cube has heat energy and so does a glass of lemonade.

6 0

3 years ago