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3 years ago

Which of the following elements would you expect to be most reactive, based

Chemistry

1 answer:

ki77a [65]3 years ago

8 0

Answer:

C. Lithium

Explanation:

This image describes the trend in reactivity. Group 1 metals are always the most reactive so yeah :)

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Five students performed a Kjeldahl nitrogen analysis of a protein sample. The following weight % nitrogen values were determined

Sunny_sXe [5.5K]

Answer:

G_calculated = 1.756

The outlier should be rejected, as G_cal > G_tab (= 1.463) at 95 % confidence.

Explanation:

The Grubb's test is used for identifying an outlier in data, which is from the same population. For this, a statistical term, G, is calculated for the suspected outlier. If the calculated value is greater than the tabulated G value then the suspected value is rejected. This term is given as,

G_calculated = | suspect value - mean| / s

Here, suspect value is 13.8, mean is to be taken of all the data (including suspected value). s is the standard deviation of the sample data.

s is calculated from the following formula:

s = (Σ(xi - x)²/(N-1))^1/2

Here, x is the mean, which is 15.24, xi is individual value and N is the total number of data (5).

From the above formula, s is found to be

Standard Deviation, s = 0.820

Now for G value,

G_calculated = | 13.8 - 15.24| / (0.820)

G_ calculated = 1.756

The tabulated G value at 95 % confidence and N -1 (5 - 1 = 4) degree of freedom is, 1.463.

As calculated G (1.756) is greater than the tabulated G (1.463), the value 13.8 is considered an outlier at 95 % confidence.

3 0

3 years ago

Which characteristic of water helps it form droplets?

inessss [21]

Answer: C. High surface tension

Explanation:

Water has high specific heat as it require high heat to raise the temperature of 1 g of water through $1^0C$ .

Surface tension is the net downward force acting on the surface of liquids due to the cohesive nature of liquids.

Water molecules are bonded by strong hydrogen bonding between the hydrogen atom and the electronegative oxygen atom making it polar. Thus water molecules present on the surface are strongly attracted by the molecules present below the surface and thus act as a stretched membrane.

The surface acquires a minimum surface are and thus acquire a spherical shape.

3 0

3 years ago

Determine the frequency of light with a wavelength of 2.672 x 10^-7cm

yaroslaw [1]

Answer:

Determine the frequency of light with a wavelength of 2.775⋅10−7 cm. Answer in units of Hz?❤

8 0

2 years ago

If 125 cal are added to 56,0 g of solid iron, what is the change in temperature of the iron? The specific heat of iron

stealth61 [152]

There is the internet

4 0

2 years ago

The compound dioxane, which is used as a solvent in various industrial processes is composed of C,H, and O atoms. Combustion of

Lady_Fox [76]

Answer:

The correct formula of dioxane is C₄H₈O₂.

Explanation:

Given data:

mass of dioxane= 2.23 g

mass of water = 1.802 g

mass of carbon dioxide = 4.401 g

molar mass of dioxane = 88.1 g / mol

Molecular formula of dioxane = ?

Solution:

percentage of carbon = (4.401 g/2.23 g ) × (12 /44) × 100

= (1.98 × 0.273) × 100 = 54.1

percentage of hydrogen = (1.802 g/ 2.23 g) × (2.016 /18.016) × 100

= (0.81 × 0.112) × 100 = 9.072

percentage of oxygen = 100 - (54.1 + 9.072)

= 100 - 63.172 = 36.828

Now we will determine the number of grams atoms of carbon, hydrogen and oxygen.

No. of gram atoms of carbon = 54.1 /12 = 4.51

No. of gram atoms of hydrogen = 9.072 / 1.008 = 9

No. of gram atoms of oxygen = 36.828 / 16 = 2.302

Atomic ratio:

C :H :O 4.51/ 2.302 : 9 / 2.302 : 2.302 /2.302

C :H :O 2 : 4 : 1

Molecular formula:

Molecular formula = n × (empirical formula)

n = molar mass of compound / empirical formula mass

empirical formula mass= 2 × 12 + 4 × 1.008 + 1 × 16

empirical formula mass= 24+ 4.032 +16 = 44.032

n = 88.1 / 44.032 = 2

Molecular formula = n × (empirical formula)

Molecular formula = 2 × (C₂H₄O)

Molecular formula = C₄H₈O₂

8 0

3 years ago