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2 years ago

Select the correct answer.

2 answers:

4 0

D.) black text on a yellow background. There is much more contrast in the colors black and yellow than the other choices.

Igoryamba2 years ago

4 0

D black text on yellow background

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During the combustion of a peanut that weighed 0.341 g, the temperature of the 100 mL of water in the calorimeter rose from 23.4

blondinia [14]

Answer:

119 kCal per serving.

Explanation:

The heat energy necessary to elevates water's temperature from 23.4°C to 37.9°C can be calculated by the equation below:

Q = mcΔT

Q: heat energy

m: mass in g

c: specific heat capacity in cal/g°C

ΔT = temperature variation in °C

m is the mass of water, considering the density of water to be 1g/mL, 100 mL of water weights 100g. Therefore:

Q = 100 g x 1.00 cal/g°C x (37.9 - 23.4)°C

Q = 1450 cal

1450 cal ____ 0.341 g peanuts

x ____ 28 g peanuts

x = 119061.58 cal

This means that the cal from fat per serving of peanuts is at least 119 kCal.

3 0

3 years ago

What is the formula for the compound formed by calcium ions and chloride ions? (1) CaCl (2) CaCl2 (3) CaCl3 (4) Ca2Cl

amid [387]

I think it would be c

6 0

3 years ago

How many H2O molecules are in 183.2 grams of H20 gas?

jek_recluse [69]

Answer: There are $61.24 \times 10^{23}$ molecules present in 183.2 grams of $H_{2}O$ gas.

Explanation:

Given: Mass = 183.2 g

Number of moles is the mass of substance divided by its molar mass.

As molar mass of water is 18 g/mol. Therefore, moles of $H_{2}O$ are calculated as follows.

$Moles = \frac{mass}{molar mass}\\= \frac{183.2 g}{18 g/mol}\\= 10.17 mol$

According to the mole concept, there are $6.022 \times 10^{22}$ molecules present in one mole of a substance.

Hence, molecules present in 10.17 moles are calculated as follows.

$10.17 mol \times 6.022 \times 10^{23}\\= 61.24 \times 10^{23}$

Thus, we can conclude that there are $61.24 \times 10^{23}$ molecules present in 183.2 grams of $H_{2}O$ gas.

6 0

3 years ago

Find the molarity of 131 g Ba(NO3)2 dissolved in 750.0 water

storchak [24]

Answer:

6.68 x 10^-4

Explanation:

131g ÷ 261.337g/mol = 0.5012685 moles

0.5012685 moles ÷ 750.0 liters =

0.5012685÷ 750.0=0.000668358

6.68 x 10^-4

8 0

1 year ago

For the following species, draw a Lewis structure for one important resonance form. Include all lone pair electrons and assign f

Gemiola [76]

Answer:

The Lewis structures are shown in the figure

Explanation:

The lewis structure will be drawn using following steps

i) we will calculate the total number of valence electrons in the molecule

ii) will assign one bond (two electrons in between two atoms)

iii) then distribute the rest of the valence electrons as lone pair or shared pair based on completion of octet.

The structure of each molecule is given in the figure.

Valence electrons:

$NO_{2}^{+}$

V.E = 5 +(2)6-1=16

$NO_{2}F$

V.E =5 +(2)6+7=24

6 0

3 years ago