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2 years ago

how much heat energy is needed to raise the temperature of 78.4g of aluminum from 19.4 degrees c to 98.6 degrees c.

Chemistry

1 answer:

Iteru [2.4K]2 years ago

7 0

The heat that is needed to raise the temperature of 78.4 g of aluminium from 19.4 °c to 98.6°c is 5600.77 j

<u><em>calculation</em></u>

Heat(Q) = mass(M) x specific heat capacity (C) x change in temperature(ΔT)

where;

Q=?

M = 78. 4 g

C=0.902 j/g/c

ΔT=98.6°c -19.4°c =79.2°c

Q is therefore = 78.4 g x 0.902 j/g/c x 79.2°c =5600.77 j

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Can alkenes react with potassium dichromate

posledela

NO alkenes can not react with potassium dichromate

7 0

3 years ago

A chemist must prepare 300.0mL of nitric acid solution with a pH of 0.70 at 25°C. He will do this in three steps: Fill a 300.0mL

d1i1m1o1n [39]

<u>Answer:</u> The volume of concentrated solution required is 9.95 mL

<u>Explanation:</u>

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

$pH=-\log[H^+]$

We are given:

pH = 0.70

Putting values in above equation, we get:

$0.70=-\log[H^+]$

$[H^+]=10^{-0.70}=0.199M$

1 mole of nitric acid produces 1 mole of hydrogen ions and 1 mole of nitrate ions.

Molarity of nitric acid = 0.199 M

To calculate the volume of the concentrated solution, we use the equation:

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the molarity and volume of the concentrated nitric acid solution

$M_2\text{ and }V_2$ are the molarity and volume of diluted nitric acid solution

We are given:

$M_1=7.0M\\V_1=?mL\\M_2=0.199M\\V_2=350mL$

Putting values in above equation, we get:

$7.0\times V_1=0.199\times 350.0\\\\V_1=\frac{0.199\times 350}{7.0}=9.95mL$

Hence, the volume of concentrated solution required is 9.95 mL

6 0

2 years ago

Merits of modern periodic table?

ANEK [815]

Answer:

<h3>Merits of modern periodic table:</h3>

The wrong position of some elements like argon, potassium, cobalt and nickel due to atomic weights have been solved by arranging the elements in the order of increasing atomic number without changing their own places.
The isotopes of some element have the same atomic numbers. Therefore, they find the same position in periodic table.
It separates metals from non-metals.
The groups of the table are divided into sub groups A and B due to their dissimilar properties which make the study of elements specific and easier.
The representative and transition elements have been separated.

Hope this helps...

Good luck on your assignment...

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2 years ago

What is the relationship between concentration and rate of reaction?

grigory [225]

<h3><u>Answer;</u></h3>

Directly proportional

<h3><u>Explanation;</u></h3>

<em><u>Concentration is one of the factors that determine the rate of a reaction. Reaction rates increases with increase in the concentration of the reactants, which means they are directly proportional.</u></em>
An increase in the concentration of reactants produces more collisions and thus increasing the rate at which the reaction is taking place. Therefore, <u>Increasing the concentration of a reactant increases the frequency of collisions between reactants and will cause an increase in the rate of reaction.</u>

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3 years ago

How many grams of potassium sulfate should be weighed to prepare 100 ppm of potassium in 250mL of solution if the purity of the

KIM [24]

Answer:

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3 years ago