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IceJOKER [234]
3 years ago
10

If you could help me that would be awesome

Chemistry
1 answer:
elixir [45]3 years ago
8 0
There are 3 significant figures. Significant numbers are the numbers that build up your total number. 1-9 always count, 0 only counts if it’s after another number. For example: 0,901 has 3 significant numbers as does 0,910. 9,10 also has 3. 0,09 has just 1.
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Complete this equation for the dissociation of na2co3(aq). omit water from the equation because it is understood to be present.
Savatey [412]
Net overall dissociation:
Na2CO3 ---> 2Na(-) + CO3(2-)

*The ion charge is in parenthesis
6 0
3 years ago
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The conversation of cyclopropane to propene in the gas phase is a first order reaction with a rate constant of 6.7x10-⁴s-¹. a) i
Rus_ich [418]

Answer: a)  The concentration after 8.8min is 0.17 M

b) Time taken for the concentration of cyclopropane to decrease from 0.25M to 0.15M is 687 seconds.

Explanation:

Expression for rate law for first order kinetics is given by:

t=\frac{2.303}{k}\log\frac{a}{a-x}

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process  

a) concentration after 8.8 min:

8.8\times 60s=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\log\frac{0.25}{a-x}

\log\frac{0.25}{a-x}=0.15

\frac{0.25}{a-x}=1.41

(a-x)=0.17M

b) for concentration to decrease from 0.25M to 0.15M

t=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\log\frac{0.25}{0.15}\\\\t=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\times 0.20

t=687s

7 0
3 years ago
Labels of many food products have expiration dates, at which point they are typically removed from the supermarket shelves. A pa
White raven [17]

Answer:

Explanation:

Since it first order, we use order rate equation

In ( \frac{A1}{A0}) = -kt where A1 is the final quality = 0.8 (80%), A0 is the initial quality = 1 ( 100%)

also, t half life = \frac{In2}{k} where k is rate constant

k = \frac{In 2}{45 days} = 0.0154

In ( \frac{0.8}{1}) = - 0.0154 t

-0.223 / -0.0154 = t

t = 14.49 approx 14.5 days from the date the yogurt was packaged

6 0
3 years ago
Which of the following chemical equations proves that the law of conservation of mass is in effect?
bogdanovich [222]

Answer:

2KCl + F₂   →     2KF + Cl₂

Explanation:

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

This law was given by French chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

2KCl + F₂   →     2KF + Cl₂

In this equation mass of reactant and product is equal. There are 2 potassium 2 chlorine and fluorine atoms on both side of equation it means mass remain conserved.

All other options are incorrect because mass is not conserved.

Mg₂ + LiBr ---> LiMg + Br

In this equation mass of magnesium is more on reactant side.

Na +O₂ ---> Na₂O

In this equation there is more oxygen and less sodium on reactant side while there is more sodium and less oxygen on product side.

H₂O ---> H₂ + O₂

In this equation there is less oxygen on reactant side while more oxygen on product side.

5 0
3 years ago
Choose the number of significant figures indicated. 90
kvv77 [185]
There are 2 significant figures. All numbers in a whole number are significant.
3 0
3 years ago
Read 2 more answers
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