There are several differences between a physical and chemical change in matter or substances. A physical change in a substance doesn't change what the substance is. In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.

3 0

2 years ago

Carbon-14 has a half-life of 5720 years and this is a fast-order reaction. If a piece of wood has converted 75 % of the carbon-1

Nana76 [90]

Answer:

11445.8years

Explanation:

Half-life of carbon-14 = 5720 years

First we have to calculate the rate constant, we use the formula :

7 0

3 years ago

If an element has a half life of one million years, how long will it take to be completely gone

Aleonysh [2.5K]

It should be 2 million years

3 0

2 years ago

Identify the double displacement reaction. 3Pb 2h 3PO 4 ⟶ 3H 2 Pb 3(PO 4) 2 2NO 2 ⟶ 2O 2 N 2 2NaBr Ca(OH) 2 ⟶ CaBr 2 2NaOH 2NH 3

IRISSAK [1]

Reaction 3 is the double displacement reaction.

Double displacement reaction occurs when the negatively and the positively charged ions of the compounds interchange their position when the new compound in the product is formed.

<h3>Which is a double displacement reaction?</h3>

In the <u>first reaction</u>, the element lead (Pb) is not an ion and no exchange of the cations or the anions occurs hence it is not a double displacement reaction.

In the <u>second reaction</u>, one compound is getting split into two new compounds and is a decomposition reaction.

In the <u>third reaction</u>, $\rm Br^{-}$ in $\rm 2NaBr$ and $\rm (OH)_{2}$ in $\rm Ca(OH)_{2}$ are anions and cations and exchanges their places to produce two new compounds $\rm CaBr_{2} + 2NaOH.$

In the <u>fourth reaction</u>, a single compound is generated as the result of the combination reaction and hence, it is not the double displacement reaction.

Therefore, $\rm 2NaBr + Ca(OH)_{2} \rightarrow CaBr_{2} + 2NaOH$ is the double displacement reaction.

Learn more about double displacement reaction here:

brainly.com/question/10091171

3 0

1 year ago