Measure the mass of a truckful of grain, use:

Explain why you would want to keep some, but not all, receipts as part of your financial records.

miss Akunina [59]

Answer:

Explanation:

Let's try and figure out the ones you don't keep.

Receipts from the dollar tree. You can't return what you bought and you only paid a dollar. It's not worth it.

Food receipts. You can't return it and unless you want to itemize what you spend / month and on what, they don't serve any purpose.

Now figure out which ones you would want to keep

1. Anything pertaining to medical perscriptions. I don't know how it works in the United States, but in Canada we are allowed to deduct only medications with a DIN number.

2 Anything that you would use for travelling that is not for pleasure (ie it is a business expense). So if you are a salesman and your territory is from A to B you would deduct meals, mileages, motels if you must stay away from home

3 In the states some tax receipts are deductible, so you might want to save those.

6 0

3 years ago

Read 2 more answers

Hello, everyone!

marusya05 [52]

Answer: 27.09 ppm and 0.003 %.

First, for air pollutants, ppm refers to parts of steam or gas per million parts of contaminated air, which can be expressed as cm³ / m³. Therefore, we must find the volume of CO that represents 35 mg of this gas at a temperature of -30 ° C and a pressure of 0.92 atm.

Note: we consider 35 mg since this is the acceptable hourly average concentration of CO per cubic meter m³ of contaminated air established in the "National Ambient Air Quality Objectives". The volume of these 35 mg of gas will change according to the atmospheric conditions in which they are.

So, according to the law of ideal gases,

PV = nRT

where P, V, n and T are the pressure, volume, moles and temperature of the gas in question while R is the constant gas (0.082057 atm L / mol K)

The moles of CO will be,

n = 35 mg x $\frac{1 g}{1000 mg}$ x $\frac{1 mol}{28.01 g}$

→ n = 0.00125 mol

We clear V from the equation and substitute P = 0.92 atm and

T = -30 ° C + 273.15 K = 243.15 K

V = $\frac{0.00125 mol x 0.082057 \frac{atm L}{mol K} x 243 K}{0.92 atm}$

→ V = 0.0271 L

As 1000 cm³ = 1 L then,

V = 0.0271 L x $\frac{1000 cm^{3} }{1 L}$ = 27.09 cm³

Then the acceptable concentration c of CO in ppm is,

c = 27 cm³ / m³ = 27 ppm

To express this concentration in percent by volume we must consider that 1 000 000 cm³ = 1 m³ to convert 27.09 cm³ in m³ and multiply the result by 100%:

c = 27.09 $\frac{cm^{3} }{m^{3} }$ x $\frac{1 m^{3} }{1 000 000 cm^{3} }$ x 100%

c = 0.003 %

So, the acceptable concentration of CO if the temperature is -30 °C and pressure is 0.92 atm in ppm and as a percent by volume is 27.09 ppm and 0.003 %.

5 0

3 years ago

What was Thomson's model of the atom called?

trasher [3.6K]

The answer is C: The plum-pudding model

3 0

3 years ago

Small quantities of hydrogen can be prepared by the addition of hydrochloric acid to zinc. a sample of 195 ml of hydrogen was co

Vikentia [17]

Let's go over the given information. We have the volume, temperature and pressure. From the ideal gas equation, that's 4 out of 5 knowns. So, we actually don't need Pvap of water anymore. Assuming ideal gas, the solution is as follows:

PV=nRT
Solving for n,
n = PV/RT = (753 torr)(1 atm/760 torr)(195 mL)(1 L/1000 mL)/(0.0821 L·atm/mol·K)(25+273 K)
n = 7.897×10⁻³ mol H₂

The molar mass of H₂ is 2 g/mol.

Mass of H₂ = 7.897×10⁻³ mol * 2 g/mol = 0.016 g H₂

5 0

3 years ago

Read 2 more answers

What are the limitations of litmus paper and Phenolphthalein indicators? Name to other indicators that can be used that do not h

jenyasd209 [6]

Answer:

Here's what I find.

Explanation:

An indicator is usually is a weak acid in which the acid and base forms have different colours. Most indicators change colour over a narrow pH range.

(a) Litmus

Litmus is red in acid (< pH 5) and blue in base (> pH 8).

This is a rather wide pH range, so litmus is not much good in titrations.

However, the range is which it changes colour includes pH 7 (neutral), so it is good for distinguishing between acids and bases.

(b) Phenolphthalein

Phenolphthalein is colourless in acid (< pH 8.3) and red in base (> pH 10).

This is a narrow pH range, so phenolphthalein is good for titrating acids with strong bases..

However, it can't distinguish between acids and weakly basic solutions.

It would be colourless in a strongly acid solution with pH =1 and in a basic solution with pH = 8.

(c) Other indicators

Other acid-base indicators have the general limitations as phenolphthalein. Most of them have a small pH range, so they are useful in acid-base titrations.

The only one that could serve as a general acid-base indicator is bromothymol blue, which has a pH range of 6.0 to 7.6.

5 0

3 years ago