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natali 33 [55]
3 years ago
8

This runner completed a 100 meter race with a time of 13.75 seconds. what was her average speed

Chemistry
2 answers:
erica [24]3 years ago
8 0

s = 100/13.75

s = 7.272727…/1

<span>s = 7.27m/s </span>
VARVARA [1.3K]3 years ago
3 0

Answer: 7.27 m/s

Explanation: The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval.

Distance traveled= 100 m

Time taken = 13.75 s

Average speed=\frac{\text {distance traveled}}{\text {Time taken}}

Average speed=\frac{100m}{13.75s}=7.27m/s

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Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2
Elena L [17]

Mass of carbon monoxide : 0.95 g

<h3>Further explanation</h3>

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.

Reaction

Fe₂O₃(s) + 3CO(g) → 2Fe(s) + 3CO₂

MW Fe₂O₃ : 159,69 g/mol

mol Fe₂O₃ :

\tt \dfrac{1.8}{159.69}=0.0113

mol ratio Fe₂O₃ : CO = 1 : 3, so mol CO :

\tt 3\times 0.0113=0.0339

mass CO (MW =  28,01 g/mol) :

\tt m=mol\times MW\\\\m=0.0339\times 28.01\\\\m=0.950~g

4 0
3 years ago
The sulfur content of an ore is determined gravimetrically by reacting the ore with concentrated nitric acid and potassium chlor
katen-ka-za [31]

Answer:

13.92 %

Explanation:

Mass of BaSO_4 = 12.5221 g

Molar mass of BaSO_4 = 233.43 g/mol

The formula for the calculation of moles is shown below:

moles = \frac{Mass\ taken}{Molar\ mass}

Thus,

Moles= \frac{12.5221\ g}{233.43\ g/mol}

Moles of BaSO_4 = 0.0536 moles

According to the given reaction,

Ba^{2+}_{(aq)}+SO_4^{2-}_{(aq)}\rightarrow BaSO_4_{(s)}

1 mole of BaSO_4 is formed from 1 mole of SO_4^{2-}

Thus,

0.0536 moles of BaSO_4 is formed from 0.0536 moles of SO_4^{2-}

Moles of SO_4^{2-} = 0.0536 moles

Moles of sulfur in 1 mole SO_4^{2-} = 1 mole

Moles of sulfur in 0.0536 mole SO_4^{2-} = 0.0536 mole

Molar mass of sulfur = 32.065 g/mol

Mass = Moles * Molar mass = 0.0536 * 32.065 g = 1.7187 g

Mass of ore = 12.3430 g

Mass % = \frac{Mass\ of\ Sulfur}{Mass_{ore}}\times 100 = \frac{1.7187}{12.3430}\times 100 = 13.92 %

3 0
4 years ago
After 15 minutes, 30 g of a sample of polonium-218 remain unchanged. If the original sample had a mass of 960 g, what is the hal
Keith_Richards [23]
Q1. The answer is 3 minutes.

Let's first calculate the remaining amount in percent:
If 960g is 100 percent (starting amount), 30 g is how many percents:
960 g : 100% = 30 g : x
x = 30 g * 100% / 960 g = 3.125% = 0.03125

Now, using the formula to calculate the number of half-lives:
(1/2)ⁿ = x,
where
x is the remaining amount: x = 0.03125
n is the number of half-lives
1/2 stands for half-life.

(1/2)ⁿ = 0.03125
⇒ n*log(1/2) = log(0.03125) 
    n = log(0.03125)/log(1/2) = log(0.03125)/log(0.5) = -1.505/-0.301 ≈ 5

The number of half-lives is 5.
Now, <span>the number of half-lives (n) is a quotient of total time elapsed (T) and length of half-life (L):
n = T/L
We know:
n = 5
T = 15 min
L = ?

Thus
L = T/n
L = 15 min/5 = 3 minutes

Q2. Filtration should be chosen.
Filtration and distillation are used to separate mixtures - filtration for the separation of heterogeneous mixtures and </span>distillation for the separation of homogeneous mixtures. Imagine that your pile of soil is a mixture. It consists of different components (the leaves, acorns, twigs), so it is the heterogeneous mixture. Therefore, to separate the leaves, acorns, twigs you will use filtration.
5 0
4 years ago
What is the volume, in liters, of 576 grams of so2 gas at stp?
katen-ka-za [31]
The volume  in  liters  of  576 grams  of SO2  gas  at STP  is   calculated as below

calculate the moles of SO2 = mass/molar  mass

= 576 g/64 g /mol  = 9 moles

At  STP  1mole =22.4 L
what  9 mole =? liters

by cross  multiplication

= 22.4 L x  9 moles/ 1moles = 201.6 liters
5 0
3 years ago
What are different types of measurements in chemistry (make sure it's relevant)?
REY [17]

Units of the SI System

There are seven base units in the SI system:

the kilogram (kg), for mass

the second (s), for time

the kelvin (K), for temperature

the ampere (A), for electric current

the mole (mol), for the amount of a substance

the candela (cd), for luminous intensity

the meter (m), for distance

Hope this helps! <3

3 0
4 years ago
Read 2 more answers
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