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3 years ago

How many kilojouls are required at 0c to melt an ice cube with a mass of 25g

Chemistry

1 answer:

Musya8 [376]3 years ago

3 0

The heat of fusion (melting) of ice is 80 cal/g. So

25 g ice x (80 cal/g) = 2000 cal
Anna

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Calculate the root means square velocity of nitrogen molecules in 25 degrees Celsius

Mademuasel [1]

Calculate the root mean square velocity of nitrogen molecules at 25°C.
297 m/s
149 m/s
515 m/s
729 m/s

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3 years ago

A student obtains the following data: Mass of empty, dry graduated cylinder: 21.577 g Volume added of NaCl solution: 4.602 mL Ma

klasskru [66]

Answer: The density of NaCl solution is 3.930 g/mL

Explanation:

We are given:

Mass of cylinder, $m_1$ = 21.577 g

Mass of NaCl and cylinder combined, M = 39.664 g

Mass of NaCl, $m_2$ = $(M-m_1)=(39.664-21.577)g=18.087g$

To calculate density of a substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

We are given:

Mass of NaCl = 18.087 g

Volume of NaCl solution = 4.602 mL

Putting values in above equation, we get:

$\text{Density of NaCl}=\frac{18.087g}{4.602mL}\\\\\text{Density of NaCl}=3.930g/mL$

Hence, the density of NaCl solution is 3.930 g/mL

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3 years ago

A chemical reaction was carried out three times. The mass of the product was 8.93 g for the first trial, 8.94 g for the second t

joja [24]

The three mass value measure are precise mass

explanation

precise mass is term use to describe data from experiment that have been repeated several times. An experiment that yield tightly grouped set of data it has a high precision. 8.93 , 8.94 and 8.92 are precise mass since they have repeated severally

6 0

3 years ago

The measure of how closely a set of measurements are to each other is the best definition for which of the following terms. a er

ahrayia [7]

D. precision. At first glance you can mark out A and B because the answers does not relate to the question. If question had said "what do you call it when the measurement is close to the actual answer" then you would have picked C. So that leaves you D. precision.

6 0

3 years ago

You work for a cutlery manufacturer who wants to electrolytically precipitate 0.500 g of silver onto each piece of a batch of 25

ICE Princess25 [194]

Answer:

373.1 mL of AgCN (aq) must be poured into your electrolysis vat to ensure you have sufficient Ag to plate all of the forks.

Explanation:

Mass of silver to be precipitated on ecah spoon = 0.500 g

Number of silver spoons = 250

Total mass of silver = 250 × 0.500 g = 125 g

$Moles (n)=Molarity(M)\times Volume (L)$

Moles of AgCN = n = $\frac{125 g}{134 g/mol}=0.9328 mol$

Volume of AgCN solution =V

Molarity of the AgCN = 2.50 M

$V=\frac{0.9328 mol}{2.50 M}=0.3731 L=373.1 mL$

(1 L = 1000 mL)

373.1 mL of AgCN (aq) must be poured into your electrolysis vat to ensure you have sufficient Ag to plate all of the forks.

6 0

3 years ago