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Degger [83]
3 years ago
10

Please help me I need these answers

Chemistry
1 answer:
lianna [129]3 years ago
8 0
Question 4: C
question 5: D
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It took 55 days for a radioactivity of 1.75 x 1012 Bq to remain 0.135 Ci. What is the half-life of this radioactivity?
Mnenie [13.5K]

From the calculations, the half life of the material is 6.5 days.

<h3>What is radioactivity?</h3>

The term radioactivity has to do with the spontaneous disintegration of a specie.

Uisng the formula;

N=Noe^-kt

N= amount at time t = 0.135 Ci or 4.995 ×10^9 Bq

No = amount initially present =  1.75 x 10^12 Bq

k = rate constant = ?

t = time taken = 55 days

Hence;

4.995 ×10^9  = 1.75 x 10^12e^-55k

4.995 ×10^9/1.75 x 10^12 = e^-55k

2.85 * 10^-3 = e^-55k

ln2.85 * 10^-3 = -55k

k = ln2.85 * 10^-3/-55

k = 0.1066 day-1

Half life = 0.693/ 0.1066 day-1

= 6.5 days

Learn more about radioactivity:brainly.com/question/1770619

#SPJ1

4 0
2 years ago
A.Which facilities contribute the most to recycling and the least to recycling based on the pie chart graphic?
nirvana33 [79]

Answer:

a) To determine the facilities that contribute the most to recycling check the pie chart and select the facility with the largest portion while to determine the facilities that contribute the least to recycling check the pie chart and select the facility with the smallest portion

b) Energy is saved because the products which are recycled usually require less energy to turn them into usable materials

c) It saves energy through recycling. It helps sustains the environment. It decrease the emission of green house gases

Explanation:

The question is not complete

a) Pie chart is the graphical representation of information in which the information is represented in a circle. The circle is divided into segments and the portion with the largest segment has the highest percentage.

To determine the facilities that contribute the most to recycling check the pie chart and select the facility with the largest portion while to determine the facilities that contribute the least to recycling check the pie chart and select the facility with the smallest portion

b) Extraction and processing of raw resources to make end products requires a lot of energy.  With recycling energy is saved because the products which are recycled usually require less energy to turn them into usable materials

c) It saves energy through recycling. It helps sustains the environment. It decrease the emission of green house gases.

6 0
3 years ago
What type of atom is hydrogen with an atomic mass of 1 and 2 electrons
Charra [1.4K]

Answer:

This would be the hydride ion where H gains an electron from a metal such as  Na

Explanation:

7 0
4 years ago
A scientific experiment must be
Blababa [14]
Repeatable

If it’s repeatable and you get the same answer constantly then it’s a good and accurate experiment
6 0
3 years ago
What are 5 reasons to be grateful of your teachers for?
4vir4ik [10]

Answer:

5 reasons to be grateful of your teachers for is

-->They open our minds to new possibilities. ...

-->They work very hard for us. ...

-->They never give up on us. ...

-->They turn our weaknesses into strengths. ...

-->They are our best guides. ...

7 0
3 years ago
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