All categories

3 years ago

Scientists have measured a cheetah running across the savannah at 70 m/s. Which of the foolowing pieces of

Chemistry

1 answer:

CaHeK987 [17]3 years ago

7 0

Answer:

You haven't provided us with ' the following pieces of

data'

You might be interested in

Who established atomic numbers as the basis for organizing the periodic table?

Jobisdone [24]

Answer:

Henry Moseley.

Explanation:

Hello,

Henry Moseley's work stated that it is better to organize the periodic table in the light of the atomic number (which accounts for the amount of protons and electrons) instead of the atomic mass, because atomic numbers are not arbitrarily assigned as long as they have the aforesaid physical basis.

Best regards.

3 0

3 years ago

True or false: A skeleton equation in chemistry shows the relative amounts of all materials in the reaction

Neko [114]

Answer:

false im pretty sure.

4 0

3 years ago

A 5.00-mL sample of blood was treated with trichloroacetic acid to precipitate proteins. After centrifugation, the resulting sol

Anarel [89]

Explanation:

According to the Beer-lambert' s law,

Absrobance = absrobptitvity × lenght × concentration

So, if we will plot a graph between absrobance and concentration then we will obtain a straight line

Hence, formula to calculate slope of the graph is as follows.

The slope of graph = $\frac{\text{difference in absrobance at two points}}{\text{difference in concentrations at those points}}$

The given data is as follows.

$A_{1}$ = 0.412 (first point)

$A_{2}$ = 0.642 (second point)

$C_{1}$ = 0.240 ppm (first point)

$C_{2}$ = 0.475 ppm (second point)

Hence, putting these values into the above formula we will calculate the value of slope as follows.

Slope = $\frac{\text{difference in absrobance at two points}}{\text{difference in concentrations at those points}}$

= $\frac{0.642 - 0.412}{0.475 - 0.240}$

= $\frac{0.23}{0.235}$

= 0.978

It is known that for the graph, line equation can be written as follows.

y = mx + c ........... (1)

where, C = intercept

m = slope

Hence, calculate the value of intercept as follows.

0.412 = $0.24 \times 0.978$ + c

c = 0.178

As it is given that the absorbance values 0.454 (the y-axis value). Therefore, putting this value into equation (1) we get the following.

y = mx + c

0.454 = $x \times 0.978$ + 0.178

0.276 = 0.978x

x = 0.282 ppm

Thus, we can conclude that the concentration of Pb in the given sample is 0.282 ppm.

3 0

4 years ago

What is the specific heat of a substance if a mass of 10.0 kg increases in temperature from 10.0°C to 70.0°C when 2,520 J of hea

Ksju [112]

Answer:

A. 0.00420 J/(gi°C)

Explanation:

i got it rigt

8 0

3 years ago

For the reaction a2 + b2 → 2ab, ea(fwd) = 105 kj/mol and ea(rev) = 77 kj/mol. assuming the reaction occurs in one step, calculat

Lady bird [3.3K]

Answer is: 28 kJ.
Chemical reaction: A₂ + B₂ ⇄ 2AB.
Ea(forward) = 105 kJ/mol.
Ea(reverse) = 77 kJ/mol.
ΔH(reaction) = ?
<span>The enthalpy change of reaction is the change in the energy of the reactants to the products.
</span>ΔH(reaction) = Ea(forward) - Ea(reverse).
ΔH(reaction) = 105 kJ/mol - 77 kJ/mol.
ΔH(reaction) = 28 kJ/mol; this is endothermic reaction (ΔH <span>> 0).</span>

6 0

3 years ago