Answer:
half lives passed=5
given sample=90g
sample left=2.8125g
Explanation:
no. of half lives=total time/half life
no.=19days/3.8days
no.=5 days
after 5 half lives sample left=2.8125g
The percent composition of the compound is 79.87 % of carbon and 20.12% of hydrogen
Explanation:
Given:
mass of carbon = 13.18 grams
mass of hydrogen = 3.32 grams
percent composition of compound =?
From the given data total mass of the compound is calculated
13.8 + 3.32
= 16.5 grams
The individual percentage of hydrogen and carbon will be calculated as:
percent composition =
x 100
For carbon,
x 100
percent composition of carbon = 79.87 % of carbon.
for hydrogen:

= 20.12 % of hydrogen
In the compound given 79.87 % of carbon and 20.12% of hydrogen is present.
The appropriate scatter plot that depicts the correct division for using Divide center to draw trend line is the plot D.
<h3>What are Scatter plots?</h3>
Scatter plots are used to show how much one variable affects another by plotting data points on a horizontal and vertical axis. Each row in the data table is represented by a marker, the position of which is determined by the values of the columns set on the X and Y axes. Scatter plots are graphs that show the relationship of two variables in a data set. It is a two-dimensional plane or a Cartesian system that represents data points.
In order to draw a trend line correctly, divide the points using the divide center method. The dividing vertical line must be drawn at the midpoint (a position where the number of data points to the left and right of the vertical line is equal).
Only option D has a vertical line dividing the 6 data points into two equal portions when the options are evaluated based on this condition.
The diagram is attached.
Learn more about scatter plot on:
brainly.com/question/24307855
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Ans: The fluorescent-colored rock stacks rise from the desert floor more than 20 miles south of the Las Vegas Strip. Crafted from local limestone, the boulders were painted in fluorescent hues before being stacked. The towers are between 25 and 35 feet tall.
Answer:

Explanation:
<u>Given reaction is:</u>
3X + 2Y → 5C + 4D
<u>In this reaction, we have:</u>
For 3 moles of X, 4 moles of D
So,
4D = 3X
Divide both sides by 4
D = 3X/4
Multiply both sides by 21
21D = 3X/4 × 21
21D = 3*21X/4
21D = 63X/4
21D = 15.75X
So, to produce 21 moles of D, we need 15.75 moles of X.
![\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Crule%5B225%5D%7B225%7D%7B2%7D)
Hope this helped!
<h3>~AH1807</h3>