Answer:
The second student with mass 70kg has more momentum
Explanation:
Using the formula:
p = m × v
Where;
p = momentum (kgm/s)
m = mass (kg)
v = velocity (m/s)
According to this question, two students are running in a cross country race.
Student 1 has the following; m = 60kg, v = 7m/s
Student 2 has the following; m = 70kg, v = 7m/s
Using p = mv
Student 1, p = 60 × 7 = 420 kgm/s
Student 2, p = 70 × 7 = 490 kgm/s
From the result of the above calculations, student 2 with mass 70kg has more momentum.
Answer:
Write down the phases and what happens during each phase.
Explanation:
Answer:
Explanation:
Accuracy is defined is as the ability to perfectly repeat results in an experiment. It is simply reproducing the same set of result with little to no altercation.
Precision is nearness of the result to the true value.
(a) Checking for consistency in the weight of chocolate chip cookies: 17.27 g, 13.05 g, 19.46 g, 16.92 g
The result above is neither accurate nor precise. We can see a lot of inconsistencies in the readings shown and no repeatability whatsoever.
(b) Testing the volume of a batch of 25- mL pipettes: 27.02mL, 26.99 mL, 26.97 mL, 27.01 mL
The results here are accurate but not precise. They are a little bit off the 25mL mark but the experiment was able to reproduce nearly the same result.
(c)Determining the purity of gold: 99.9999%, 99.9998%, 99.9999%
This result is both precise and accurate. Pure Gold should be 100% and our values are very close. The experiment also was able to generate very accurate results.
These are two questions and two answers.
1) Question: Which of the following pairs of reactants will react together to produce water (H2O) as one of the products?
<span>Fe(OH)₃ and CuO
Cu(OH)₂ and H₂S
MgO and Ca(OH)₂
SO₃ and H₂O
</span>
<span>Answer:
</span>
<span>Cu(OH)₂ and H₂S
</span>
Justification:
1) Fe(OH)₃ and CuO: to form water Cu and Fe should react with each other. Being them two metals, they will not do that. So this reaction is not possible.
2) Cu(OH)₂ and H₂S: Being S a non metal and Cu a metal, they can react to form a the salt CuS, and water, as per this equation:
<span>Cu(OH)₂ + H₂S → CuS + 2H₂O
</span>
<span>
3) MgO and Ca(OH)₂: Being Mg and Ca two metals they will not react with each other, so this reaction is not feasible.
</span>
<span>4) SO₃ and H₂O: this is an acid oxide and water reaction which yields to an acid, as per this equation:
</span>
<span>SO₃ + H₂O → H₂SO₄
</span>
Which is not producing water
<span>2) Question: Based on reactivity, which of the following elements can replace
aluminum (Al) in a compound during a single replacement reaction?
B
Ca
Zn
Fe
</span>
Answer: Ca.
Justification:
Only an element more reactive than Al will replace it <span>in a compound during a single replacement reaction.</span>
You may predict that being Ca an alkalyne earth element it is more reactive than Al and so Ca will replace Al.
Else, you have to search a reactivity table, where you will find this order of reactivity among the metals:
Ca more reactive than Al
Al more reactive than Zn
Zn more reactive than Fe.
<span />
Being B a metalloid, its matallic character is low and it is less reactive than the other metals on the list.
Answer:
The answer is 2.3
Explanation:
The model for the population of bacteria is growing by
P= 100 x e^.60t
where P is the number of colonies and t is measured in hours.
Now, we need to find after how many hours will 400 colonies be present
So, Putting value of P = 400 in the above model and obtain the value of t
-> 400 = 100 x e ^.60t
-> 4 = e^.60 t
Take the natural log of ln on both sides
--> ln 4 = ln e ^.60 t
--> ln 4 = .60t
t= ln 4 / .60
T= 2.3
