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3 years ago

11. A chemical reaction happens when chemicals combine to form a new _______

Chemistry

1 answer:

Oxana [17]3 years ago

6 0

Answer:

substances

Explanation:

A chemical reaction happens when substances break apart or combine to form one or more new substances.

^Hope it helps, Hazel^

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I need help with this please! and thank you. if you don't know, don't comment please.

cestrela7 [59]

Answer:

S4O5

Explanation:

6 0

3 years ago

A solution of H 2 SO 4 ( aq ) with a molal concentration of 1.66 m has a density of 1.104 g / mL . What is the molar concentrati

uysha [10]

Answer:

1.58 M

Explanation:

$H_2SO_4$ is 1.66 m concentration.

Which means that 1.66 moles of $H_2SO_4$ are present in 1 kg of the solvent, water.

Mass of water = 1 kg = 1000 g

Moles of $H_2SO_4$ = 1.66 moles

Molar mass of $H_2SO_4$ = 98.079 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$1.66\ mole= \frac{Mass}{98.079\ g/mol}$

$Mass_{H_2SO_4}= 162.81114\ g$

Total mass = 1000 g + 162.81114 g = 1162.81114 g

Density = 1.104 g/mL

Volume of the solution = Mass / Density = 1162.81114 / 1.104 mL = 1053.27 mL = 1.05327 L

Considering:-

Molarity = moles/ Volume of solution = 1.66 / 1.05327 M = 1.58 M

4 0

3 years ago

Calculate the pH of a 0.2 M * 4 solution for which Kb = 1.8*10^-5 at 26 c . The equation for the reaction

lara31 [8.8K]

Answer: The pH of the solution is 11.24

Explanation:

We are given:

Molarity of ammonia = 0.2 M

$K_b=1.8\times 10^{-5}$

The given chemical equation follows:

$NH_3+H_2O\rightleftharpoons NH_4^++OH^-$

I: 0.2

C: -x +x +x

E: 0.2-x x x

The expression for equilibrium constant follows:

$K_b=\frac{[NH_4^+][OH^-]}{[NH_3]}$

Putting values in above expression, we get:

$1.8\times 10^{-5}=\frac{x^2}{0.2-x}\\\\1.8\times 10^{-5}(0.2-x)=x^2\\\\x^2+(1.8\times 10^{-5}x)-(0.36\times 10^{-5})=0\\\\x=1.88\times 10^{-3}, 1.9\times 10^{-3}$

Neglecting the negative value of x as concentration cannot be negative.

So, $[OH^-]=x=1.88\times 10^{-3}M$

pOH is defined as the negative logarithm of hydroxide ion concentration present in the solution.

$pOH=-\log [OH^-]$

Putting values in above equation, we get:

$pOH=-\log (1.88\times 10^{-3})\\\\pOH=2.76$

We know:

$pH+pOH=14\\\\pH=14-2.76\\\\pH=11.24$

Hence, the pH of the solution is 11.24

6 0

3 years ago

How are work and energy related

valentinak56 [21]

The more work someone does, the more energy they need. For example, if someone is moving a large couch they are going to use a lot of energy because it is heavy. However, if the couch was smaller, they would be using less energy because it does not weigh as much as they will not become as tired!

5 0

3 years ago

Which is the most important question for deciding if a chemical reaction has occurred?

777dan777 [17]

Answer:

all these are physical properties except release of heat so it's probably heat energy given off

7 0

3 years ago

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