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3 years ago

How much energy, in joules, is released when 17 kilograms of granite is cooled from 45 C to 21 C?

1 answer:

6 0

The final answer is -322, 320 Joules. The solution for the problem is:

The equation that must be used in this problem is:

U = mCp(Tf-Ti)

where:
U = energy released or absorbed in Joules
m = mass in kg
Cp = specific heat of material in J/kg-C
Tf = final temperature, C
Ti = initial temperature, C

Looking up the Cp of granite gives a value of 790 J/kg-C.

U = 17kg (790 J/kg-C) (21-45)
U = - 322, 320 Joules (negative means heat is released)

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In a boys hostel, 1206 eggs were bought for breakfast for the students. How many moles of eggs does this represent?

Evgen [1.6K]

Answer:

6.022×1023

Here, it has been asked how many eggs are in one mole of eggs. The eggs represent the unit which can be atom, ion or molecule. So by the definition of mole, 6.022×1023number of eggs are present in one mole of eggs.

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2 years ago

What happens to raisins or other dried fruits in breakfast cereals when you pour milk over them? why?

viktelen [127]

Dried fruits and raisins get terribly soggy after being drenched in milk for a long period of time. They act like a sponge, absorbing all of the milk up making them wet and "soggy". I prefer them to be like that when I eat my cereal in the morning.

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3 years ago

What is the classification of a solution of naoh with a ph of 8.3?

Maksim231197 [3]

Answer:

Alkaline or basic solution (alkaline and basic means the same)

Explanation:

According to the pH, solutions may be classified as neutral, acidic, or alkaline (basic).

This table shows such classification:

pH classification

7 neutral

> 7 alkaline or basic

< 7 acidic

Thus, since the pH of the solution is 8.3, which is greater than 7, the solution is classified as basic (alkaline).

Additionally, you must learn that pH is a logarithmic scale for the concentration of hydronium ions in the solution.

pH = - log [H₃O⁺]

You can calculate the concentration of hydronium ions using antilogarithm properties:

$pH=-log[H_3O^+]\\ \\ {[H_3O^+]}=10^{-pH}\\ \\ {[H_3O^+]}=10^{-8.3}=0.00000000501$

NaOH solutions are alkaline solutions, bases, according to Arrhenius model, because they contain OH⁻ ions and release them when ionize in water.

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3 years ago

An iron pipe has a density of 7.86 g/mL and a volume of 324.4 mL. What is the mass of the iron pipe?

wlad13 [49]

Answer:

$Mass=2549.784 \ g$

Explanation:

The equation for mass is:

$Mass = Density * Volume$

We plug in the given values into the equation:

$Mass = 7.86 \ g/mL * 324.4 \ mL$

$Mass=2549.784 \ g$

6 0

2 years ago

Identify each of these substances as acidic, basic, or neutral. pure water, pH = 7.0 lake water, pH = 6.5 baking soda solution,

Alex_Xolod [135]

Answer:

pure water, pH = 7.0 (Neutral)

lake water, pH = 6.5 (Acidic)

baking soda solution, pH = 9 (Alkaline)

soapy water, pH = 12 (Alkaline)

Explanation:

The degree of acidicity or alkalinity of a solution can be determined on a pH meter. A pH below 7 is acidic; a pH of 7 is neutral; a pH value of above 7 is alkaline.

5 0

3 years ago

Read 2 more answers