Chemistry Questions & Answers

In chemistry labs, broken glass CANNOT go into the normal trash bins. (True or False) True False

There are several ways to calculate the enthalpy of a reaction, \( \Delta H_{r x n} \). Three methods were involved in the enthalpy lab. In the method of \( \Delta H_{r x n}=-q_{s o l n} \), the [Select] used. In the method of Hess's law, [Select] theoretical prediction as if under the standard conditions, [Select] is used.

3. 2.17 paveiksle pavaizduotas aušinamo švino temperatūros kitimo grafikas. a) Kokią agregatinę būseną atitinka jo dalys \( A B, B C \) ir \( C D \) ? b) Kokius vyksmus vaizduoja kiekviena grafi- ko atkarpa? c) Kaip vadinamas pavaizduotas virsmas ir kiek jis truko? d) Nustatykite švino lydymosi temperatūrą.

How many moles are in 29.5 grams of Na?

Calculate the volume of 2.4 mol of nitrogen gas at \( 28^{\circ} \mathrm{C} \) and 110 kPa pressure.

Cercise 1-9 A sample of gas has a volume of 4.50 L at a pressure of 800 mmHg . The volume of the gas is increased to 8.00 L (the temperature remains constant). What is the pressure of the gas now?

Which of the following statements is true regarding the conservation of mass? Mass can be created during a chemical reaction. Mass can be destroyed during a chemical reaction. Mass is neither created nor destroyed during a chemical reaction.

How much heat is required to raise the temperature of 100.0 mL of water from \( 12.00^{\circ} \mathrm{C} \) to \( 18.00^{\circ} \mathrm{C} \) ? - Round the answer to three significant figures, - The specific heat capacity of water is \( 4.184 \frac{\mathrm{~J}}{\mathrm{~g}^{\circ} \mathrm{C}} \). The density of water is \( 1.000 \frac{\mathrm{~g}}{\mathrm{~mL}} \),

6.1 Methane gas is one of the hydrocarbons that is used as a source of fuels worldwide. When methane reacts with oxygen, water and carbon dioxide are formed. Atoms of water molecules in the above reaction are bonded by a covalent bond. 6.1.1 Define the term covalent bond. 6.1.2 Write down the balanced chemical equation. Consider the following balanced equation of a chemical reaction. 6.2.1 The chemical formula of compound X in the above reaction 6.2.2 The type of bond that exists in compound \( X \) 6.2.3 The Lewis structure of compound \( X \) [9] QUESTION 7 Study the illustrations of the diagrams below and answer the questions which follow.

A 45.0 g piece of metal with specific heat \( 0.450 \frac{\mathrm{~J}}{\mathrm{~g}^{\circ} \mathrm{C}} \) and at \( 115^{\circ} \mathrm{C} \) is placed in \( 200 . \mathrm{g} \) of water at \( 25.0^{\circ} \mathrm{C} \). What will be the final temperature of the water? Select the correct answer below: \( 2.10^{\circ} \mathrm{C} \) \( 29.8^{\circ} \mathrm{C} \) \( 88.4^{\circ} \mathrm{C} \) \( 27.1^{\circ} \mathrm{C} \)