The answers include:
- A loaf of risen but unbaked bread - chemical change.
- Photo by Elinor D - chemical change.
- Bread dough rising - chemical change.
<h3>What is a Chemical change?</h3>
This involves the formation of a new products from substances. In this scenario, a rising bread contains alcohol which evaporates.
Photographs also fall under this category and is therefore an irreversible chemical change.
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The concentration of the original calcium ions is 0.005 M
<h3>What is concentration?</h3>
The term concentration has to do with the amount of substance in solution. We know that the concentration can be measured in a lot of units such as mole/litre, grams per litre, percentage and so on.
As such we have the equation;
Ca^2+(aq) + (NH4)2CrO4(aq) --------> CaCrO4(s) + 2NH4^+(aq)
Number of moles of the precipitate = 346.7 * 10^-3 g/156 g/mol
= 0.0022 moles
Now;
1 mole of Ca^2+ produces 1 mole of CaCrO4 hence 0.0022 moles of CaCrO4 was produced by 0.0022 moles of CaCrO4.
Given that the volume of the solution is 0.440 L, the concentration of the solution is; 0.0022 moles/0.440 L
= 0.005 M
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Temperature, cloud cover and thunder are all examples of weather.
<h3><u>Explanation:</u></h3>
Weather is described as conditions that prevail for a short period of time and the above-mentioned factors change variably throughout the day. Cloud cover simply describes the clouds coverage in the sky. It is one factor that is used to describe weather conditions since the type of clouds indicates prevailing weather.
For example, the presence of cirrus means there will be a storm in 24 to 48 hours. Weather conditions characterized by thunder is said to be stormy and it also has other conditions such as lightning, wind and fast rain with heavy raindrops. Temperature affects the warmness and coldness of the air and its movement. Moreover, it also affects all other aspects of weather conditions.
The half-life of the substance is 3.106 years.
<h3>What is the formula for exponential decay?</h3>
- The exponential decline, which is a rapid reduction over time, can be calculated with the use of the exponential decay formula.
- The exponential decay formula is used to determine population decay, half-life, radioactivity decay, and other phenomena.
- The general form is F(x) = a.
Here,
a = the initial amount of substance
1-r is the decay rate
x = time span
The equation is given in its correct form as follows:
a = 
×
As this is an exponential decay of a first order reaction, t is an exponent of 0.8.
Now let's figure out the half life. Since the amount left is half of the initial amount at time t, that is when:
a = 0.5 a0
<h3>Substituting this into the equation:</h3>
0.5 = ×
0.5 =
taking log on both sides
t log 0.8 = log 0.5
t = log 0.5/log 0.8
t = 3.106 years
The half-life of the substance is 3.106 years.
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Answer:
there are more hydrogen ions than hydroxide ions in the solution. This kind of solution is acidic. A base is a substance that accepts hydrogen ions.
Explanation:
An acid is a substance that donates hydrogen ions. ... Now there are more hydrogen ions than hydroxide ions in the solution. This kind of solution is acidic. A base is a substance that accepts hydrogen ions. When a base is dissolved in water, the balance between hydrogen ions and hydroxide ions shifts the opposite way.
