All categories

2 years ago

What happens during a chemical change??

Chemistry

2 answers:

Alenkasestr [34]2 years ago

6 0

I think it's b because of the different choices you have don't make sense to me

borishaifa [10]2 years ago

5 0

Hmmm.. i think B. I dont understand the the answer choices.

You might be interested in

How many grams of H2O are in 34.2 grams of NAOH Need ASAP

Brrunno [24]

Answer:

15.438g H2O

Explanation:

First you need to find the reaction equation:

2H2O+2Na=2NaOH + H2

Hydrogen is a diatomic molecule so it will have a subscript of 2 on the right hand side. From there we can balance the reaction.

Then we can use stoichiometry:

34.2g NaOH * (1 mol NaOH/39.908g NaOH) * (2 mol H2O/2 mol NaOH) * (18.015g H2O/1 mol H20) = 15.438g H2O

It is important that when you use stoichiometry that all your units cancel out until you only have the unit you want.

3 0

1 year ago

2) Examine the molecules below. Circle the molecules that can also be classified as compounds.

sergejj [24]

Answer:

3rd

Explanation:

its the way they look

4 0

1 year ago

Consider the generic reaction: 2 A(g) + B(g) → 2 C(g). If a flask initially contains 1.0 atm of A and 1.0 atm of B, what is the

irina1246 [14]

Answer:

b. 1.5 atm.

Explanation:

Hello!

In this case, since the undergoing chemical reaction suggests that two moles of A react with one moles of B to produce two moles of C, for the final pressure we can write:

$P=P_A+P_B+P_C$

Now, if we introduce the stoichiometry, and the change in the pressure $x$ we can write:

$P=1.0-2x+1.0-x+2x$

Nevertheless, since the reaction goes to completion, all A is consumed and there is a leftover of B, and that consumed A is:

$x=\frac{1.0atm}{2}=0.5atm$

Thus, the final pressure is:

$P=1.0-2(0.5)+1.0-(0.5)+2(0.5)\\\\P=1.5atm$

Therefore the answer is b. 1.5 atm.

Best regards!

3 0

2 years ago

Determine the molality of a solution of methanol dissolved in ethanol for which the mole fraction of methanol is 0.135. Give you

Alja [10]

Answer: The molality of the solution is 0.11 m

Explanation:

We are given:

Mole fraction of methanol = 0.135

This means that 0.135 moles of methanol is present in 1 mole of a solution

Moles of ethanol = 1 - 0.135 = 0.865 moles

To calculate the mass for given number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of ethanol = 0.865 moles

Molar mass of ethanol = 46 g/mol

$0.865mol=\frac{\text{Mass of ethanol}}{46g/mol}\\\\\text{Mass of ethanol}=(0.865mol\times 46g/mol}=39.79g$

To calculate the molality of solution, we use the equation:

$Molality=\frac{m_{solute}\times 1000}{M_{solute}\times W_{solvent}\text{ (in grams)}}$

Where,

$m_{solute}$ = Given mass of solute (methanol) = 0.135 g

$M_{solute}$ = Molar mass of solute (methanol) = 32 g/mol

$W_{solvent}$ = Mass of solvent (ethanol) = 39.79 g

Putting values in above equation, we get:

$\text{Molality of methanol}=\frac{0.135\times 1000}{32\times 39.79}\\\\\text{Molality of methanol}=0.106m\approx 0.11m$

Hence, the molality of the solution is 0.11 m

6 0

2 years ago

Why do scientists think there is an undiscovered carbon sink somewhere?

dedylja [7]

The major carbon sources (reservoirs that release more carbon than absorbed) are: deforestation and fossil fuels

The major carbon sinks (reservoirs that absorb more carbon than released) are:
soil, oceans and plants.

When scientists calculate the amount of carbon dioxide is returned to the atmosphere vs the released the amount of carbon, a large amount is unaccounted for and the total does not add up. This is why scientists believe there is an undiscovered carbon sink somewhere.

6 0

2 years ago

Read 2 more answers