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4 years ago

Express the product of 9.0 x 10^-4m and 8.1 x 10^4m using the correct number of significant digits

Chemistry

1 answer:

Assoli18 [71]4 years ago

7 0

Answer:

7.3 × 10¹ m²

Explanation:

The language "product" means that we must multiply the numbers given to get our answer.

9.0 × 10⁻⁴ m × 8.1 × 10⁴ m = 7.3 × 10¹ m²

The significant figures rule for multiplication is that we must us the amount of significant figures in the number with the least significant figures, in this question this is 2 significant digits from both 9.0 × 10⁻⁴ m and 8.1 × 10⁴ m.

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1) When solid Fe metal is put into an aqueous solution of NiSO4, solid Ni metal and a solution of FeSO4 result. Write the net io

k0ka [10]

Fe + NiSO4 ----> FeSO4 + No

NaF + HI ---> NaI + HF

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3 years ago

Old thermometers contained very small amounts of mercury. The mercury in the photo has a melting point of -38.8 degrees Celsius.

Nikolay [14]

Answer:

••It's melting point equals -38.8 degrees Celsius because it is mercury. |••

Explanation:

This one makes the most sense out of the answers.

7 0

3 years ago

How many atoms are there in 7.80 moles of germanium

Orlov [11]

<h3>Answer:</h3>

4.70 × 10²⁴ atoms Ge

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

<u>Chemistry</u>

<u>Atomic Structure</u>

Using Dimensional Analysis
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

<h3>Explanation:</h3>

<u>Step 1: Define</u>

7.80 mol Ge

<u>Step 2: Identify Conversions</u>

Avogadro's Number

<u>Step 3: Convert</u>

$\displaystyle 7.80 \ mol \ Ge(\frac{6.022 \cdot 10^{23} \ atoms \ Ge}{1 \ mol \ Ge} )$ = 4.69716 × 10²⁴ atoms Ge

<u>Step 4: Check</u>

<em>We are given 3 sig figs. Follow sig fig rules and round.</em>

4.69716 × 10²⁴ atoms Ge ≈ 4.70 × 10²⁴ atoms Ge

8 0

3 years ago

An ideal gas (C}R), flowing at 4 kmol/h, expands isothermally at 475 Kfrom 100 to 50 kPa through a rigid device. If the power pr

Zina [86]

<u>Answer:</u> The rate of heat flow is 3.038 kW and the rate of lost work is 1.038 kW.

<u>Explanation:</u>

We are given:

$C_p=\frac{7}{2}R\\\\T=475K\\P_1=100kPa\\P_2=50kPa$

Rate of flow of ideal gas , n = 4 kmol/hr = $\frac{4\times 1000mol}{3600s}=1.11mol/s$ (Conversion factors used: 1 kmol = 1000 mol; 1 hr = 3600 s)

Power produced = 2000 W = 2 kW (Conversion factor: 1 kW = 1000 W)

We know that:

$\Delta U=0$ (For isothermal process)

So, by applying first law of thermodynamics:

$\Delta U=\Delta q-\Delta W$

$\Delta q=\Delta W$ .......(1)

Now, calculating the work done for isothermal process, we use the equation:

$\Delta W=nRT\ln (\frac{P_1}{P_2})$

where,

$\Delta W$ = change in work done

n = number of moles = 1.11 mol/s

R = Gas constant = 8.314 J/mol.K

T = temperature = 475 K

$P_1$ = initial pressure = 100 kPa

$P_2$ = final pressure = 50 kPa

Putting values in above equation, we get:

$\Delta W=1.11mol/s\times 8.314J\times 475K\times \ln (\frac{100}{50})\\\\\Delta W=3038.45J/s=3.038kJ/s=3.038kW$

Calculating the heat flow, we use equation 1, we get:

[ex]\Delta q=3.038kW[/tex]

Now, calculating the rate of lost work, we use the equation:

$\text{Rate of lost work}=\Delta W-\text{Power produced}\\\\\text{Rate of lost work}=(3.038-2)kW\\\text{Rate of lost work}=1.038kW$

Hence, the rate of heat flow is 3.038 kW and the rate of lost work is 1.038 kW.

4 0

3 years ago

What are alternative periodic tables

aksik [14]

Tabulations of chemical elements differing in their organization from the traditional seen periodic system

5 0

3 years ago