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3 years ago

Define and differentiate between accuracy and precision

1 answer:

6 0

Accuracy is the closeness of a measurement to the true value. Precision is the closeness of agreement among a set of results.

Suppose you read a refrigerator thermometer five times and get the Celsius readings 39.0, 39.3, 39.0, 39.1, and 39.0.

The average temperature is 39.1 °C. Your readings are precise because most of the readings are within 0.1 °C of the average.

However, if the actual refrigerator is 37.0 °C, your readings are not accurate because they are off by about 2°C.

If you use a thermocouple and get an average reading of 37.00, 37.03, 37.00, 37.01,and 37.00, your readings are both accurate and more precise than those from the refrigerator thermometer.

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An experiment reveals that 125.0 grams of an unknown metal increases in temperature from 22.0 oC to 43.6 oC upon absorbing 640 j

nydimaria [60]

Answer:

Cp = 0.237 J.g⁻¹.°C⁻¹

Explanation:

Amount of energy required by known amount of a substance to raise its temperature by one degree is called specific heat capacity.

The equation used for this problem is as follow,

Q = m Cp ΔT ----- (1)

Where;

Q = Heat = 640 J

m = mass = 125 g

Cp = Specific Heat Capacity = ??

ΔT = Change in Temperature = 43.6 °C - 22 °C = 21.6 °C

Solving eq. 1 for Cp,

Cp = Q / m ΔT

Putting values,

Cp = 640 J / (125 g × 21.6 °C)

Cp = 0.237 J.g⁻¹.°C⁻¹

3 0

3 years ago

PLEASE HELP!!

NARA [144]

We can skip option B and D because NaCl is salt and H₂SO₄ is a strong acid.
Neutralization reactions are those reactions in which acid and base react to form salt and water.
As water being amphoteric in nature can react with HCl as follow,

HCl + H₂O ⇆ H₃O⁺ + OH⁻

In this case no salt is formed, so we can skip this option.

Ammonia being a weak base can abstract proton from HCl as follow,

HCl + NH₃ → NH₄Cl

Ammonium Chloride is a salt. So, among all four options, Option-C is the correct answer.

3 0

3 years ago

Read 2 more answers

What is chemical reaction ?

butalik [34]

Answer: Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products.

Explanation:

7 0

3 years ago

Which of the following is NOT a benefit of using renewable energy sources?

Afina-wow [57]

Answer:

D, They produce fossil fuels

Explanation:

you can't just pull them out of nowhere

3 0

3 years ago

Read 2 more answers

At 2000°C, the equilibrium constant for the reaction below is Kc = 4.10 ´ 10–4 . If 0.600 moles of NO is placed in a 1.0-L react

erastova [34]

Answer:

At equilibrium, the concentration of $N_{2 (g)}$ is going to be 0.30M

Explanation:

We first need the reaction.

With the information given we can assume that is:

$N_{2 (g)}$ + $O_{2 (g)}$ ⇄ 2 $NO_{(g)}$

If there is placed 0.600 moles of NO in a 1.0-L vessel, we have a initial concentration of 0.60 M NO; and no $N_{2 (g)}$ nor $O_{2 (g)}$ present. Immediately, $N_{2 (g)}$ and $O_{2 (g)}$ are going to be produced until equilibrium is reached.

By the ICE (initial, change, equilibrium) analysis:

I: [ $N_{2 (g)}$ ]=0 ; [ $O_{2 (g)}$ ]= 0 ; [ $NO_{(g)}$ ]=0.60M

C: [ $N_{2 (g)}$ ]=+x ; [ $O_{2 (g)}$ ]= +x ; [ $NO_{(g)}$ ]=-2x

E: [ $N_{2 (g)}$ ]=0+x ; [ $O_{2 (g)}$ ]= 0+x ; [ $NO_{(g)}$ ]=0.60-2x

Now we can use the constant information:

$K_{c}=\frac{[products]^{stoichiometric coefficient} }{[reactants]^{stoichiometric coefficient} }$