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3 years ago

According to the law of conservation of matter, which statement about chemical reactions is true?

1 answer:

4 0

The law of conservation of matter basically states that matter can’t be created or destroyed, only changed in form, so you can rule out any option that mentions destroying or creating matter. That leaves only option A. Atoms cannot be created or destroyed by chemical reactions.

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How do you cure a stuffy nose?

lisov135 [29]

A) Take a very spicy chilli and chew it it will clear up
b) Drink hot water
c) Take medicine
d) Exercise for a long time till it makes you drench it helps

4 0

3 years ago

(a) The absorbance of mixture at 400 nm was 0.40.

laiz [17]

Answer:

0.1 g/dl

Explanation:

The standard curve is a graph that relates the absorbance at 400 nm with the concentration of haemoglobin in mg/dl. To obtain the concentration from the absorbance value, we enter in the x-axis (absorbance at 400 nm) with the value 0.40 (the line between 0.2 and 0.6), we extrapolate the line to the curve and read the correspondent value on y-axis (concentration in mg/dl): 100 mg/dl.

So, we convert the concentration from mg/dl to g/dl by dividing into 1000:

100 mg/dl x 1 g/1000 mg = 0.1 g/dl

Therefore, the concentration of haemoglobin of the patient is 0.1 g/dl.

6 0

3 years ago

Write a balanced chemical equation, including physical state symbols, for the decomposition of solid sodium azide (NaN3) into so

LenaWriter [7]

Answer:

39g

Explanation:

Details of the solution is shown below. From the information provided regarding the N2 produced, we could calculate the amount of N2 produced and use that to find the mass of sodium azide reacted.

5 0

3 years ago

There are three sets of sketches below, showing the same pure molecular compound (hydrogen chloride, molecular formula ) at thre

RideAnS [48]

Answer:

The correct answer is - option C.

Explanation:

Given: the melting point of HCl is

-114.8 °C, which suggests that below this temperature HCl will be solid.

and, since the boiling point of HCl is - 85.1 °C. It is also suggested that above this temperature HCl will be gas, Therefore.

Solid -114.8 - Ordered arrangement

Liquid -85.1c - Less orderly arranged

Gaseous - Least orderly arranged

Thus, at —90 °C, HCl will be present 'in the liquid state, At — 1 °C, HCl will be present in the gaseous state and at -129 °C, HCl will be present in the solid-state. So, the molecules will be organized in a more orderly manner .

Thus, the correct answer is - option C

8 0

3 years ago

Unit 1- Unit Assessment (Matter & Density)

konstantin123 [22]

Answer:

<h3>The answer is 11 g/mL</h3>

Explanation:

The density of a substance can be found by using the formula

$density = \frac{mass}{volume} \\$

From the question

mass = 3025 g

volume = 275 mL

We have

$density = \frac{3025}{275} \\$

We have the final answer as

Hope this helps you

7 0

3 years ago