A book has a mass of 2.2 kilograms. what is the weight on earth?

How are continental drift and plate tectonics related

harina [27]

The continent rest on massive slabs of rocks called tectonics

4 0

3 years ago

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2. Why does a chemical equation need to be balanced?

arlik [135]

Answer:

Chemical equations must be balanced to satisfy the law of conservation of matter, that states that matter cannot be produced or destroyed in a closed system. The law of conservation of mass governs the balancing of a chemical equation.

Explanation:

7 0

3 years ago

What do the parentheses mean in a chemical reaction and how they are used

galben [10]

Parantheses mean present of a subgroup or a group of polyatomic ions in a chemical reaction.

Explanation:

In a chemical reaction, sometimes, a compound may be composed of group of polyatomic ions with other ions. Some of the polyatomic ions are sulfate, carbonate, nitrate, hydroxide, bicarbonate, ammonia etc.

So these polyatomic ions are formed by combining two or more elements. Thus, if the number of polyatomic ions in a compound is more than one, then we use parathesis and write those polyatomic ions in it and write the number of polyatomic ions present in the compound as subscript of the parathesis.

For example, Fe₂(SO₄)₃

So here SO₄ is a polyatomic ion and in the compound 3 atoms of SO₄ is required to neutralize the compound and thus paranthesis is used. Thus, parantheses mean present of a subgroup or a group of polyatomic ions in a chemical reaction.

5 0

3 years ago

Calculate the ph of a dilute solution that contains a molar ratio of potassium acetate to acetic acid (pka ???? 4.76) of (a) 2:1

givi [52]

According to Hasselbach-Henderson equation:

$pH=pK_{a}+log\frac{[A^{-}]}{[HA]}$

Here, $[A^{-}]$ is concentration of conjugate base and [HA] is concentration of acid.

In the given problem, conjugate base is $CH_{3}COOK$ and acid is $CH_{3}COOH$ thus, Hasselbach-Henderson equation will be as follows:

$pH=pK_{a}+log\frac{[CH_{3}COOK]}{[CH_{3}COOH]}$ ...... (1)

(a) Ratio of concentration of potassium acetate and acetic acid is 2:1 thus,

$\frac{[CH_{3}COOK]}{[CH_{3}COOH]}=2$

Also, $pK_{a}=4.76$

Putting the values in equation (1),

$pH=4.76+log\frac{2}{1}=5.06$

Therefore, pH of solution is 5.06.

(b) Ratio of concentration of potassium acetate and acetic acid is 1:3 thus,

$\frac{[CH_{3}COOK]}{[CH_{3}COOH]}=\frac{1}{3}$

Also, $pK_{a}=4.76$

Putting the values in equation (1),

$pH=4.76+log\frac{1}{3}=4.28$

Therefore, pH of solution is 4.28.

(c)Ratio of concentration of potassium acetate and acetic acid is 5:1 thus,

$\frac{[CH_{3}COOK]}{[CH_{3}COOH]}=\frac{5}{1}$

Also, $pK_{a}=4.76$

Putting the values in equation (1),

$pH=4.76+log\frac{5}{1}=5.45$

Therefore, pH of solution is 5.45.

(d) Ratio of concentration of potassium acetate and acetic acid is 1:1 thus,

$\frac{[CH_{3}COOK]}{[CH_{3}COOH]}=1$

Also, $pK_{a}=4.76$

Putting the values in equation (1),

$pH=4.76+log\frac{1}{1}=4.76$

Therefore, pH of solution is 4.76.

(e) Ratio of concentration of potassium acetate and acetic acid is 1:10 thus,

$\frac{[CH_{3}COOK]}{[CH_{3}COOH]}=\frac{1}{10}$

Also, $pK_{a}=4.76$

Putting the values in equation (1),

$pH=4.76+log\frac{1}{10}=3.76$

Therefore, pH of solution is 3.76.

4 0

3 years ago

A chemical reaction is occurring inside a beaker and the temperature of the beaker is monitored. What would the contents of the

Archy [21]

Answer:

The system is the Answer

Explanation:

System is the region which is taken into consideration.

While we perform a chemical reaction the system is the substance taken in the container.

So, A thermodynamic system is the amount of matter or the region in universe which is under the study.

The region outside the beaker are called as surroundings.

The beaker (the surface which separates the system from its surroundings) is said to be the boundary

System + surroundings = universe

3 0

3 years ago