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2 years ago

3. Why are nutrients needed for living things? Describe the difference between living and nonliving things.

1 answer:

8 0

Nutrients are synthetic substances found in each living thing on Earth. They are important to the existences of individuals, plants, animals, and any remaining organisms. Nutrients assist break with bringing down food to give organisms energy. ... The main nutrients they need are carbon, hydrogen, and oxygen.

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Meanders are characteristics of a young river. True False

Rainbow [258]

True would be the answer

7 0

2 years ago

A goldsmith melts 12.4 grams of gold to make a ring. The temperature of the gold rises from 26°C to 1064°C, and then the gold me

DiKsa [7]

Problem One

You will use both m * c * deltaT and H = m * heat of fusion.

Givens

m = 12.4 grams

c = 0.1291

t1 = 26oC

t2 = 1204

heat of fusion (H_f) = 63.5 J/grams.

Equation

H = m * c * deltaT + m * H_f

Solution

H = 12.4 * 0.1291 * (1063 - 26) + 12.4 * 63.5

H = 1660.1 + 787.4

H = 2447.5 or 2447.47 is the exact answer. I have to leave the rounding to you. I have no idea where to round it although I suspect 2450 would be right for 3 sig digs.

Problem Two

Formula and Givens

t1 = 14.5

t2 = 50.0

E = 5680

c = 4.186

m = ??

E = m c * deltaT

Solution

5680 = m * 4.186 * (50 - 14.5)

5680 = m * 4.186 * (35.5)

5680 = m * 148.603 * m

m = 5680 / 148.603

m = 38.22 grams That isn't very much. Be very sure you are working in joules. You'd leave that many grams in the kettle after drying it thoroughly.

m = 38.2 to 3 sig digs.

8 0

2 years ago

Read 2 more answers

Consider the following operations on the number 7.02 times 10^-2. Without using a calculator, decide which would give a signific

mariarad [96]

Answer: (a). Significantly Larger value

(b). Significantly Smaller value

(c). Significantly Larger value

(d). Significantly Smaller value

Explanation:

This is quite a dicey question to analyze, let us not get too carried away with the simplicity of the mathematical signs involved.

Given that 7.02 × 10⁻² is the number to be compared with.

(a). 7.02 × 10⁻² + 6.10 × 10⁵

from this, we can see a very large number being added to the base number involved, although the base number is carrying a negative power, it does not affect the other greatly.

ANS: the sum would give a significantly larger value

(b). 7.02 × 10⁻² - 6.10 × 10⁵

Here, we can see a very large number subtracted from the base number having a negative power.

the subtraction of this numbers gives a Significantly smaller value than the base number i.e. 7.02 × 10⁻²

ANS: Significantly smaller value

(c). 7.02 × 10⁻² × 6.10 × 10⁵

we would solve this from our basic knowledge of indices

where ⇒ (10ᵃ × 10ᵇ = 10ᵃ⁺ᵇ)

we have,

7.02 × 10⁻² × 6.10 × 10⁵ = (7.02 × 6.10) × 10⁻²⁺⁵ = (7.02 × 6.10) × 10³

this final value (multiplication value) gives a Significantly larger value.

ANS: Significantly larger value

(d). 7.02 × 10⁻² ÷ 6.10 × 10⁵

Also, we apply the indices rule for Division

where ⇒ (10ᵃ ÷ 10ᵇ = 10ᵃ⁻ᵇ)

i.e. 7.02 × 10⁻² ÷ 6.10 × 10⁵ = (7.02 × 6.10) × 10⁻²⁻⁺⁵ = (7.02 × 6.10) × 10⁻⁷

this final value gives a Significantly Smaller value

ANS: Significantly Smaller value

cheers i hope this helps.

7 0

2 years ago

Find the enthalpy of neutralization of HCl and NaOH. 137 cm3 of 2.6 mol dm-3 hydrochloric acid was neutralized by 137 cm3 of 2.6

liraira [26]

Answer : The correct option is, (D) 89.39 KJ/mole

Explanation :

First we have to calculate the moles of HCl and NaOH.

$\text{Moles of HCl}=\text{Concentration of HCl}\times \text{Volume of solution}=2.6mole/L\times 0.137L=0.3562mole$

$\text{Moles of NaOH}=\text{Concentration of NaOH}\times \text{Volume of solution}=2.6mole/L\times 0.137L=0.3562mole$

The balanced chemical reaction will be,

$HCl+NaOH\rightarrow NaCl+H_2O$

From the balanced reaction we conclude that,

As, 1 mole of HCl neutralizes by 1 mole of NaOH

So, 0.3562 mole of HCl neutralizes by 0.3562 mole of NaOH

Thus, the number of neutralized moles = 0.3562 mole

Now we have to calculate the mass of water.

As we know that the density of water is 1 g/ml. So, the mass of water will be:

The volume of water = $137ml+137ml=274ml$

$\text{Mass of water}=\text{Density of water}\times \text{Volume of water}=1g/ml\times 274ml=274g$

Now we have to calculate the heat absorbed during the reaction.

$q=m\times c\times (T_{final}-T_{initial})$

where,

q = heat absorbed = ?

$c$ = specific heat of water = $4.18J/g^oC$

m = mass of water = 274 g

$T_{final}$ = final temperature of water = 325.8 K

$T_{initial}$ = initial temperature of metal = 298 K

Now put all the given values in the above formula, we get:

$q=274g\times 4.18J/g^oC\times (325.8-298)K$

$q=31839.896J=31.84KJ$

Thus, the heat released during the neutralization = -31.84 KJ

Now we have to calculate the enthalpy of neutralization.

$\Delta H=\frac{q}{n}$

where,

$\Delta H$ = enthalpy of neutralization = ?

q = heat released = -31.84 KJ

n = number of moles used in neutralization = 0.3562 mole

$\Delta H=\frac{-31.84KJ}{0.3562mole}=-89.39KJ/mole$

The negative sign indicate the heat released during the reaction.

Therefore, the enthalpy of neutralization is, 89.39 KJ/mole

3 0

3 years ago

What is the concentration of a solution with a volume of 660L that contains 33.4g of AlCO3?

lana [24]

Answer:

The concentration of the solution is 5.8168 × $10^{-4}$ mol. $dm^{-3}$

Explanation:

Here, we want to calculate the concentration of the solution.

The unit of this is mol/dm^3

So the first thing to do here is to calculate the number of moles of the solute present, which is the number of moles of AlCO3

The number of moles = mass/molar mass

molar mass of AlCO3 = 27 + 12 + 3(16) = 27 + 12 + 48 = 87g/mol

Number of moles = 33.4/87 = 0.384 moles

This 0.384 moles is present in 660 L

x moles will be present in 1 dm^3

Recall 1 dm^3 = 1L

x * 660 = 0.384 * 1

x = 0.384/660 = 0.00058168 = 5.8168 * 10^-4 mol/dm^3

7 0

2 years ago