Answer:
Explanation:
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In this case, since these problems about formulas, firstly require the determination of the empirical formula, assuming that the given percentages are masses, we can calculate the moles and mole ratio of oxygen to iron as shown below:
In such a way, by rounding to the first whole number we multiply by 8 and divide by 5 to obtain:
Whose molar mass is 159.69 g/mol and the mole ratio of the molecular to the empirical formula is:
479.1/159.69=3
Therefore, the molecular formulais:
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Answer:
see the pic for the answer
Answer:
It increases when a catalyst is added.
Explanation:
The following factors control reaction rates:
1. Nature of reactants
2. Concentration of the reactants or pressure of gaseous
3. Temperature
4. Presence of catalyst
5. Sunlight
The addition of a foreign body to a reaction may influence the speed of the reaction. If a foreign body increases the rate of reaction, it is a called a positive catalyst or simply a catalyst. A negative catalyst is called an inhibitor.
A catalyst is a substance that is introduced into a chemical reaction to change the rate of the reaction without itself being affected at the end of the reaction.
Catalysts helps to reduce reaction time of many slow reactions. Most catalysts are specific in their actions and works on certain reactions or substrates.
Temperature change has a considerable effect on reaction rates since temperature is directly proportional to the average kinetic energy of reacting particles. Generally, reaction rate varies as temperature directly.
Answer : The time required for decay is, 84 days.
Explanation :
Half-life of chromium-51 = 28 days
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the time required for decay.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = time taken by sample = ?
a = let initial activity of the sample = 100
a - x = amount left after decay process = 12.5
Now put all the given values in above equation, we get
Therefore, the time required for decay is, 84 days.
I think that different liquids have different freezing points because every liquid consists of different atoms and different things that make up the atom causing them to have different freezing points.
